Radio receivers

My hobby also covers the wave-surfing, but not as a radio amateur, just as a DX-er, mostly on FM (regarding its higher quality), but also on medium and short waves.

If we take a look at the history of radios, we can affirm, till the end of 80's the famous brand manufacturers target was to make exceptionally good quality equipments (like Philips, Marantz, Dual, Denon, Sony, Onkyo, Kenwood, JVC, etc). That era, until the middle of the '80s, was the best period of audio systems and receivers/tuners. After that comes a degradation in any air radio wave reception, especially on AM bands. Nowadays, if you purchase a radio, on-air bands you will meet the low quality of sound (compression used by DAB or DAB+ just theoretically can achieve the FM stereo signal quality, in reality, is less listenable), and also the low quality of receivers/tuner part (sensibility decreased, or instead of linear or PLL circuits now the conversion are made via DSPs). Since 90's the LW and MW starts to be neglected (also the SW, but this was popular at Far East/Japan, America, etc), means the sensibility of receivers decreased from 8uV to few hundred uV-s on LM and MW, pushing the consumers to use just the FM, which has a shorter coverage distance - but a higher quality of reception. Today can be seen as an expansion of internet-radios (streaming of coded/packed signals), and the FM starts to be less important. Now can be seen more and more receivers with DAB/DAB+ capability in the marketplaces, but without stations that can transmit such programs in good quality, I think will not be a success story. The DAB are forced by EU: new cars can be sold just withDAB capable radios from 1st Jan 2021.

I like mostly the analog radios regarding their sound, but I am interested also in new technologies in this field. For this reason, I collected a few radios and receivers - of course, all started from my great- and grandparents owned radios, till today's PLL digital tuned receivers, with DSP coversions and DAB capability. In most cases, I refurbish them, changing degraded components, to keep their radio- and audio-parts performance on their top level.


Some words about FM band:

The FM broadcast band is a range of radio frequencies used for FM broadcasting by radio stations (Wikipedia). In Europe, Africa and in Australia, it spans from 87.5 to 108 MHz (called also as CCIR). The FM broadcast band in Japan uses 76 to 95 MHz. The International Radio and Television Organisation (OIRT) band in Eastern Europe is from 65.8 to 74.0 MHz, with the exception of East Germany, which always used the 87.5 to 100 (later 104) MHz broadcast band, in line with Western Europe. Although these Eastern European countries now primarily use the 87.5 to 108 MHz band, as in the case of Russia, some of them have already discontinued the OIRT band and have changed to the 87.5 to 108 MHz band.
For this reason some old radios FM band goes up just till 104MHz, like in case of old DUAL or WEGA tuners/receivers.

Some words about DAB (Digital audio broadcasting) radio:

Digital audio broadcasting (DAB) is a digital radio technology for broadcasting Digital audio radio services, used in several countries across Europe and Asia Pacific.
DAB may offer more radio programs over a specific spectrum than analogue FM radio. DAB is more robust with regard to noise and multi-path fading for mobile listening, since DAB reception quality first degrades rapidly when the signal strength falls below a critical threshold, whereas FM reception quality degrades slowly with the decreasing signal.
Audio quality varies depending on the bit-rate used and material. Most stations use a bit rate of 128 kbit/s or less with the MP2 audio codec, which requires 160 kbit/s to achieve perceived FM quality. 128 kbit/s gives better dynamic range or signal-to-noise ratio than FM radio, but a more smeared stereo image, and an upper cut-off frequency of 14 kHz, corresponding to 15 kHz of FM radio. However, "CD sound quality" with MP2 is possible just "with 256...192 kbit/s" - which remains a dream using DAB.
An upgraded version of the system was released in February 2007, which is called DAB+. DAB is not forward compatible with DAB+, which means that DAB-only receivers are not able to receive DAB+ broadcasts. However, broadcasters can mix DAB and DAB+ programs inside the same transmission and so make a progressive transition to DAB+. DAB+ is approximately twice as efficient as DAB due to the adoption of the AAC+ audio codec (HE-AAC version 2 audio codec, or 'aacPlus'), and DAB+ can provide high quality audio with bit rates as low as 64 kbit/s (but will never achieve CD-s quality). Reception quality is also more robust on DAB+ than on DAB due to the addition of Reed-Solomon error correction coding. DAB uses a wide-bandwidth broadcast technology and typically spectra have been allocated for it in Band III (174-240 MHz).
Hungary has chosen DAB+ for its digital radio standard. Since 23 January 2009 Antenna Hungaria started experimental broadcasting on its DAB+ digital terrestrial radio network on one channel: 11D. From 3 January 2011, with 7 available radio programs within the frames of the experimental DAB+ broadcasting in Hungary: All above radios were transmitted on one channel 11D (222.064 MHz).
The DAB+ transmission was stoped in Hungary at 12.09.2020.


Below you can see my radios collection by manufacturers in chronological order.


Manufacturers



Aiwa


The company was founded on June 20, 1951, as AIKO Denki Sangyo Co., Ltd., manufacturing microphones, and changed its name to Aiwa Co., Ltd. on March 10, 1959. The company was a leading manufacturer of audio products, including headphone stereos, minicomponent stereo systems, portable stereo systems, minidisc players, CD, and cassette players, and car stereo systems throughout the 1970s, 1980s, and 1990s. Nearly 86 percent of company revenues were derived from such audio products.
Aiwa manufactured more than 89 percent of its output outside Japan, with a heavy emphasis on the lower-cost SouthEast Asian nations of Singapore, Malaysia, and Indonesia. The company was also heavily dependent on overseas sales, with more than 80 percent of total revenues being generated outside Japan, with 43 percent in North and South America, 25 percent in Europe, and 13 percent in areas of Asia outside Japan and in other regions.
Although not then officially an affiliated company of consumer electronics giant Sony Corporation, by 1982, Sony had a 54.6% stake in the company, effectively giving it majority control. With growing competition throughout the late 1990s, the company slid towards bankruptcy, and the troubled company was then fully purchased by Sony Corporation in 2003. However, the new direction of Aiwa under Sony did not meet consumer and sales expectations. On January 21, 2005, new product development ended, and by 2006, Aiwa products were discontinued and no longer sold in the market. Sony announced the termination of the brand entirely on May 14, 2008.


Aiwa XT003

Aiwa XT003

Is a simple, low-grade receiver made by Aiwa in Singapur 1992-94 (in some pages is mentioned between 1990-1996), predecessor of XT-005 model.

General information:

  • Digital 3 band PLL tuner (superheterodyne)
  • Frequency range: FM 87.5-108 MHz, MW 522-1611kHz, LW 144-290kHz
  • Usable sensitivity: 0.9uV on FM mono, 300uV/m on MW and 1000uV/m on LW
  • Tunning steps: LW 3kHz, MW 9kHz, FM: 25kHz
  • Preset memories: 30, mixed for AM and FM
  • Signal to noise ratio: FM 80dB in mono, 74dB on stereo, AM 52dB
  • Total harmonic distortion (1kHz): on FM 0.12% in mono, 0.2% in stereo, on AM is 0.5%
  • Alternate channel separation: 70dB on FM, and 20dB on AM
  • Stereo separation: 40dB at 1kHz
  • Frequency response: 30-15kHz, +0.5...-2dB
  • Output signal level: 700mV
  • AM (MW) suppression ratio: on FM 50dB
  • Power source: 220Vac, 50Hz
  • Power consumption: 7W
  • Dimension: 430 x 73 x 255 mm (W x H x D)
  • Weight: 2.5 kg
  • Original price at 1992: 350 DM

Good things:

  • Is a 4 gang tuner on FM with a good sensibility
  • The sound at AM reception is clear, low background noise
  • Has a Preset Scan mode: will scan the stored programs
  • Very clear display with good intensity, and can be seen from a wide-angle!

Problems:

  • The IF bandwidth cannot be selected (ex. normal and narrow)
  • No signal meter, just a Tune mark on the display
  • In stereo mode, the manual search is canceled, which means will stop just on stations with a high signal level
Is a very underrated tuner - can be purchased from 10Euro. Use mixed components, through-hole and passive SMDs soldered with wave soldering. Easily can be serviced. The power board is separated, the regulator with the heatsink is on the radio board. The heatsink is just warm, not hot - has a low heat dissipation.

Upgrades:

  • All electrolytic capacitors changed
  • Modification:
    - Audio path: all capacitors are PP, on the output (C69 and C70) were increased from 2.2uF to 4.7uF. On the output board, the ground capacitor was chagned from 0.01uF ceramic to 0.1uF PP and the 2 noise-canceling to 220pF COG ceramic.
    - Power path - mentioned just the modified values, voltage ratings remain same or higher: C33 390uF, C61 470uF, C75 390uF, C80 390uF, C83 390uF, C85 100uF, C88 4700uF, C91 100uF, C94 330uF, C206 0.22F, C205 470uF (in some places I mounted solid electrolite capacitors or tantalum, below 1uF PP type).
    - AC line input get an EMI filter formed with 1uF + 2x27mH coil + 1uF
This tuner has a pleasant, clear, and natural sound, without any extra coloration. Sometimes I feel from the bottom line are missing a bit of bass.



Akai


Akai was founded by Masukichi Akai and his son, Saburo Akai as Akai Electric Company Ltd. (Akai Denki Kabushiki Kaisha), a Japanese manufacturer in 1946. Akai's products included reel-to-reel audiotape recorders (such as the GX series), tuners (top-level AT, mid-level TR, and TT series), audio cassette decks (top-level GX and TFL, mid-level TC, HX, and CS series), amplifiers (AM and TA series), microphones, receivers, turntables, video recorders, and loudspeakers. Many Akai products were sold under the name Roberts in the US, as well as A&D in Japan (from 1987 after a partnership with Mitsubishi Electric), Tensai and Transonic Strato in Switzerland and Western Europe (until 1988). During the late 1960s, Akai adapted Tandberg's cross-field recording technologies (using an extra tape head) to enhance high-frequency recording and switched to the increasingly reliable Glass and crystal (X'tal) (GX) ferrite heads a few years later. The company's business eventually became troubled and it left the audio industry in 1991. Akai Holding filed for insolvency in November 2000. It emerged that ownership of Akai Holdings had somehow passed in 1999 to Grande Holdings, a company founded by Akai's chairman James Ting. In early 2003, Grande Holdings began undergoing a re-exposure of Akai's brands by marketing various audio-visual products manufactured by Samsung.


Akai AA-1015PL

Akai AA-1015PL


Is a middle-grade receiver made between 1977-1979 in Japan. Is the varicap version with presets of the AA-1010L model, previous model was the AA-1010DB started one year earlier, in 1976.

General information:

  • Analog 2 band receiver
  • Coverage: FM 88MHz - 108MHz, AM 520kHz - 1605kHz
  • Sensitivity: for FM 2uV (no data for stereo); for MW 200uV/m with bar antenna and 20uV with external antenna; for LW 300uV/m with bar antenna and 30uV with external antenna;
  • 5 presets just for FM via touch sensors
  • Signal to noise ratio: 65dB on FM and >45dB on AM
  • Harmonic distortion: 0.3% on mono, 0.6% on stereo FM
  • Antenna input impedance: 300 ohms balanced, 75 ohms unbalanced
  • Used intergrated circuits: AM tuner and IF: uPC30C, FM IF: LA1230Z, MPX decoder: LA3350S, touch switch controller: uPC1009C, operational amplifier LA3122 (for RIAA)
  • Output: 15W/channel on 8 ohm
  • Signal to noise ratio: Phono >75dB, AUX >90dB
  • Power bandwidth: 40 - 20kHz with 0.8% THD
  • Channel separation: better than 50dB on from Phono at 1kHz
  • Residue noise measured at the output on 8 ohms load: 0.8mV
  • Damping factor: more than 30 at 1kHz on 8ohm
  • Input sensitivity and impedance: Phono 3mV/47kohm, AUX 150mV/100kohm
  • Tape monitor: input pin/DIN 150mV/100kohm; Output pin 150mV/2kohm, DIN 30mV/30kohm
  • Frequency response: Phono/RIAA 30 - 15kHz +1dB...-1dB, Tuner/Aux/Tape monitor 10 - 70Khz 0..-2dB
  • Tone control: Bass +-10dB at 100Hz, Treble +-10dB at 10kHz
  • Loudness conttrol: +10dB at 100Hz, +5dB at 10kHz (volume control set at -30dB position)
  • Power: 220Vac, 50Hz
  • Dimensions/weight: 440 x 125 x 265 mm (WxHxD)
  • Weight: 6.2 kg
  • Preise at 1977: 600DM



Blaupunkt


Founded in 1923 in Berlin as "Ideal", the company was acquired by Robert Bosch AG in 1933. In 1938 it changed its name to "Blaupunkt", German for "blue point" or "blue dot", after the blue dot painted onto its headphones that had passed quality control. After the World War II, Blaupunkt moved its headquarters and production to Hildesheim. Blaupunkt took over a former Philips/Grundig factory in Portugal to produce automotive head units. Later, factories were set up in Tunisia (speakers) and Malaysia (speakers and electronics). At 1 March 2009 was sold to Aurelius AG of Germany. After the 2011 take-over, Blaupunkt became a managed brand name with all production outsourced to China. It filed for bankruptcy in late 2015 with liquidation proceedings completed in early 2016. The brand is now managed by GIP Development SARL of Luxembourg and is used on various product groups worldwide. Unfortunately, I did not recommend any new equipment from this brand. They are characterized by low cost and low quality.


Blaupunkt RX+ 12

Blaupunkt RX+ 12


This was my first DAB+ radio, and frankly, I was dissapointed by DAB+ reception quality, compared to FM transmission received with good tuners.

General information:

  • Digital FM and DAB+ radio with alarm clock function
  • Coverage: FM 87.5MHz - 108MHz (just one speaker, and no stereo in phones), DAB+ 170-240 MHz (band III, channels 5A-13F)
  • 50 kHz steps on FM
  • One chip radio, without any filters and resonant circuits
  • Full RDS on FM and DAB+ bands
  • 20 presets (10 for FM / 10 for DAB+) + timer memories
  • Rec out jack (stereo, line level - I never try it)
  • Frequency synthesizer DSP / microcontroller: Q88 BV158MOA or 57297AOD (I did not find any data about it on the net)
  • Other ICs:F40-100GCP 4k serial static memory, LM4871 boomer 3W audio opamp, XC6206 3.3V LDO regulator
  • Output: 1.2 W max. on 8 ohm
  • Power consumption: 3 W via 4 AAA bateries or via 5V/500mA external power plug. In standby mode: < 1 W
  • Dimensions/weight: 191 x 118 x 32 mm, 615 g (incl. batteries)
  • Produced: since 2014 by M3 Electronic GmbH under Blaupunkt brand name

Good things:

  • Quite sensible on both FM and DAB+ bands, no any more accurate specification (like service manual, info about sensibility, signal level, noise level etc.) about radio on user manual or on the net
  • Clock adjustment is instant in DAB+ mode, but also are made on FM via RDS data, but more slowly.
  • The Radio Text function is very good. You can select via Info/Alarm button

Problems:

  • High consumption, with batteries the operation is meaningless, because in 2 days are over. Stand by consumption is high (few mA-s) regarding continuous backlight of LCD.
  • Sound quality is poor, regarding one small speaker with <5 cm diameter.
  • Backlight LED is allways on - has 2 light levels, a high one when the keypad are touched, and after 40 sec goes into low level, which is still high intensity in my opinion
  • If the external power socket are taken out or in, the radio goes into standby mode, loosing all presets and time/alarm adjustments.
  • Just 10+10 presets are not enough for today's radio listening in urban life.

Upgrades:

  • Modification for AAA accumulator usage instead of batteries: one diode 1U4007 and one 100 ohm resistor added to power socket to have charging possibility using 4 pcs of NiMH AAA accumulators.
  • The radio design from outside looks like to have 2 speakers (see the picture of radio above), but is not true. On the left side the radio has a 92 grams metal weight to balance the right side speaker weight (magnet). I added one more 8 ohm 1.5W speaker (same as original one) on left side instead of weight. Speakers are connected serially, now the load is 16 ohm. Sound level seems same (theoretically should be half), and sound quality seems to be a bit better, but do not expect significant improvement.



Denon


Denon is a Japanese electronics company started in 1910 by Frederick Whitney Horn, an American entrepreneur. Denon produced the first cylinder audio media in Japan and players to play them. Decades later, Denon was involved in the early stages of development of digital audio technology, while specializing in the manufacture of high-fidelity professional and consumer audio equipment. Denon made Japan's first professional disc recorder and used it to record Emperor Hirohito's voice. For many decades, Denon was a brand name of Nippon-Columbia, including the Nippon Columbia record label. The Denon brand came from a merger of Denki Onkyo (not to be confused with the other Onkyo) and others in 1939. In 2001, Denon was spun off as a separate company with 98% held by Ripplewood Holdings and 2% by Hitachi. In 2002, Denon merged with Marantz to form D&M Holdings. On March 1, 2017, Sound United LLC completed the acquisition of D+M Holdings.


Denon TU1500RD


Denon TU1500RD

Is one of my best tuner, used especially for FM classical music programs in my audio system. Has a very good sensitivity and selectivity on FM, I can receive some stations, which I can't receive with any other tuners owned by me (excepting some Duals, Kenwoods, and Marantz tuners). Is possible to use RDS for "smart searching", for instance, you can select as an example to search only classical music or news stations, etc.

General information:

  • Manufactured by Denon in Japan between 1999 - 2006
  • Digital 2 bands (MW-FM) PLL radio with RDS+EON capability,
  • 40 memory presets
  • Coverage: MW 520kHz - 1.710MHz, FM 87.5MHz - 108.0MHz
  • Usable sensitivity: 12uV on AM, 0.9uV on FM (mono) and 16uV for stereo - via a very sensitive MOSFET FM tuner
  • FM/AM tuner IC: FM/AM tuner: LA1265, stereo decoder: LA3401, PLL freq. synthetizer: LC72131, uController: TMP87CM71F, dot matrix VFD display driver LC75711, RDS decoder: SAA6579T & LC7074
  • Output frequency range: 20Hz - 15kHz (-1...+0.5dB)
  • Signal/noise ratio: AM 53dB, FM 82dB mono, 78dB stereo
  • THD: on FM 0.08% for mono, 0.12% for stereo
  • Stereo separation: 50dB
  • Line output impedance: 100 ohm
  • Antenna input impedance for FM: 75 ohm
  • Power: 230V/50Hz, consumption: 9W
  • Dimensions: 434x75x242mm, 2.5kg

Good things:

  • Has a very clean sound, beautiful bass, low noise, good channel separation (as radio, cannot be compared with CD, SACD or DVD-A), good readable dot matrix display, perfect "narrow" IF selection feature.
  • RF-attenuation for strong stations.
  • Remote has digit button to direct access the memory and keys for RDS (I just try it, but I did not use the remote).
  • Has Radio Text
  • Has a Postdetection Filter to eliminate HD FM radio noise (used in America)

Difficult, problematic items:

  • Has no signal level indicator (could make antenna placement more easier)
  • Memory is organized like 5 x 8 = 40 positions (A:1-8, B:1-8, ... ,E:1-8). Should be more natural 4x10 = 40
  • Has just only 1 antenna input. Some tuners have 2, and for DXing could be more suitable.

DX-ing:
On dedicated webpages are recommended to modify the IF filter for FM from 230kHz bandwidth with a 150 or 110kHz type. Nowadays, ex. Murata or TDK has low loss type narrow band (150 or 130 kHz) ceramic filters. What is the advantage to change the filters with a narrow band low loss type ones? Muting the adjacent channels without sensibility decrease! I changed the narrow filter part (CF102 and CF103 position) with low loss, narrow band TDK filters: 107MJ 150kHz+-20kHz, 4.5dB loss type. Original filters were Murata type, in CF101 positions SFE10.7MXHA (low distortion, 230kHz+-25kHz), 2 pcs of SFE10.7MS3GKA (180kHz+-20kHz) at CF102 and CF103 position, and SFE10.7MM (230kHz, +-25kHz) in position CF104.
Related links:
       Audioreview, is a review site with several reviews about this tuner. Do not be surprised when you saw just 4/5 score, because some reviews referring to TU-1500AE, and are written by novice members, not technical gurus. Almost all of them write about exceptional selectivity and sensibility of this radio, mentioning no signal indicator and 5x8 memory location, and high price (at that time).
       Tuner Information Center - Vintage stereo tuners - tuners review from D to G. Is a good review of TU-1500RD tuner
       The FM Ceramic Filter Page mentioning, in general, the Denon TU-1500RD "is the best tuner for high-quality FM DX audio program listening".


Denon TU1500AE


Denon TU1500AE

Is an upgraded version of TU-1500RD - based on Denon. Personally, I have a different opinion. From design and used semiconductors can be mentioned that, but for DX-ing cannot be used (see later the explanation).

General information:

  • Manufactured by Denon in Japan between 2005 - 2010
  • Digital 2 bands (MW-FM) PLL radio with RDS+PTY+TP and Radio Text capability,
  • 100 memory presets
  • Coverage: MW 522kHz - 1.611MHz, FM 87.5MHz - 108.0MHz
  • Usable sensitivity: 18uV on AM, 1.0uV on FM (mono) and 23uV for stereo - via a very sensitive MOSFET FM tuner
  • FM/AM tuner with IF section: one module, uController: MB90C950, RDS decoder: BU1924, and opamp: SE5532
  • Output frequency range: 20Hz - 15kHz (-1...+0.5dB)
  • Signal/noise ratio: AM 50dB, FM 73dB mono, 68dB stereo
  • THD: on FM 0.15% for mono, 0.3% for stereo
  • Stereo separation: 43dB
  • Line output impedance: 300 ohm
  • Antenna input impedance for FM: 75 ohm
  • Power: 230V/50Hz, consumption: 10W, less than 1W in standby
  • Dimensions: 434x73x286mm (WxHxD), 3.6kg

Good things:

  • Has a good readable dot matrix display, good channel separation, low noise, clean sound, but not as pleasant or as musical as its predecessor, TU-1500RD.
  • RF-attenuation for strong stations.

Difficult, problematic items:

  • Has no signal level indicator (could make antenna placement more easier)
  • No any selection possibility of wide or narrow IF bandwidth
  • No direct memory recall buttons, all can be selectred via rotating knob.
  • Cannot be switched off the stereo mode (at weak signals should be better if you can switch into mono mode) or to listen something in mono.
Remarks
  • This tuner is not good for DX-ing. Is quite difficult to often change between tunning modes (manual and automatic searching modes) in case of weak signals.
  • The tuner and IF part are placed into a metal box inside, highly populated with components, which makes it difficult to change the ceramic filters and electrolytic capacitors in IF part.
  • In flyer are mentioned the output impedance is less than 300 ohm, but the output coupling capacitors value is just 10uF, which means the lowes output frequency should be around 55-60Hz
  • In several reviews are highlighted the clear sound of this tuner, but in reality, the electrolyte capacitors' quality is poor. Is better to change them with higher quality and values (ex. 47uF/25V Nichicon Fine Gold).
  • Not necessary, but improving the sound quality: changing the opamp power capacitors from 100uF/16V with 220V/16V, and using Ta capacitors around microcontroller and RDS decoder instead of electrolytic for the noise canceling, and insert the power line noise filter components on PCB, etc.
  • I did not found the Service Manual of this radio, but I recognized, the PCB is same with TU-1800DAB model, so also the related part of the schematic. Can be very helpful!

I recommend it just for daily listening, in urban area, with a lot of stations around. Is a very good tuner, but just within mentioned conditions.



Dual


In 1907, brothers Christian and Joseph Steidinger began manufacturing clockwork and gramophone parts in the Black Forest town of St. Georgen. In 1927, Gebrüder Steidinger (Steidinger Bros.) adopted the name Dual in reference to the dual-mode power supplies it pioneered. The power supplies allowed gramophones to be powered from mains electricity or with a wind-up mechanism. Soon thereafter, Dual began producing turntables of its own. After World War II, Dual became the biggest manufacturer of turntables in Europe, with more than 3,000 employees working in several factories. Throughout the 1970s, 1980s, and 1990s, Dual introduced audio cassette players, VCRs, CD players, and other consumer electronics. When Japanese consumer electronics started entering European markets in the 1970s on a large scale, Dual went bankrupt in 1982, and was sold to French electronic manufacturer Thomson SA. In 1988, Thomson sold Dual to German manufacturer Schneider Rundfunkwerke AG. After the insolvency of Schneider Rundfunkwerke AG in 2001, TCL Holdings, a Chinese company, purchased the Dual assets and brand, and it began marketing its own products under the name. In 2002, Namsung Electronics, a Korean company, bought the rights to use the name in the Americas and began selling lower-priced (but generally well-reviewed) consumer electronics under the Dual marque. The main product lines are home audio, mobile audio, marine audio and GPS receivers.


Dual CT-1250


Dual CT-1250

General information:

  • Manufactured at 1980-81 by Dual Gebrüder Steidiner St. George/Schwarzwald
  • 3 band analog PLL tuner LW, MW, and FM
  • Coverage: LW 150 - 340 kHz, MW 515 - 1620 kHz, FM 87.5 - 108.0 MHz
  • Antenna input impedance for FM: 60/75 ohm unbalanced,
  • 6 preset memory for FM
  • Usable sensitivity: 15uV on MW, 30uV on LW, 0.8 uV on FM (mono) and 25 uV for stereo
  • Intermediate frequencies: 460kHz for AM, and 10.7MHz for FM
  • AM tuner IC: TDA1072 amp, osc, IF and det; FM det. TDA1576A; stereo decoder (MPX) TDA1578; tunning indicator TBB4331A
  • Output frequency range:40Hz - 12.5kHz (-0.5...+0.5dB)
  • Power: ~220V/50Hz, consumption 15W
  • Output level and impedance: 750mV/4.7kohm
  • Dimensions: 430x55x380mm, 3.4 kg.
Has a pleasant warm sound, selectivity is very-very good. When the signal is weak, the switchback from stereo to mono is smooth, cannot be heard any noise.


Dual CT-1450

Dual CT-1450

General information:

  • Manufactured between 1981-82 by Dual Gebrüder Steidiner St. George/Schwarzwald
  • 3 band analog PLL tuner LW, MW, and FM
  • Coverage: LW 146 - 353 kHz, MW 522 - 1611 kHz, FM 87.5 - 108.0 MHz
  • Antenna input impedance for FM: 75/300 ohms unbalanced,
  • 6 preset memory for FM, and 6 for AM (LW+MW)
  • Usable sensitivity: 15uV on MW, 25uV on LV, 0.6 uV on FM (mono) and 20 uV for stereo
  • Intermediate frequencies: 455kHz for AM, and 10.7MHz for FM
  • AM tuner IC: HA1197; FM IF opamp: LA1222; FM det. uPC1167C2; stereo decoder (MPX) uPC1161; tunning indicator: LB1416; prescaller: uPB553AC; PLL freq. synthesizer and controller: uPD1703-016
  • Output frequency range:10Hz - 16kHz (for 50us pre-emphasis -3dB)
  • Automatic mono/stereo switchover (FM): 4uV
  • FM IF bandwidth: 140kHz
  • Signal to noise ratio: mono 76dB, stereo 74dB
  • Harmonic distortion_ mono 0.15%, stereo 0.2%
  • Power: ~115/230V, 50/60Hz, consumption 13W
  • Output level and impedance: 750mV/5.1kohm
  • Dimensions: 440x55x350mm, 3.4 kg.
Is the most sensitive tuner that I have (0.6uV on FM), and with the widest audio bandwidth. The sound is warm, clear, more than in the case of Marantz, Denon, or Philips.
Problem: the LW starts from 146kHz and the steps are 9kHz -> means cannot be received any LW station, because the normal LW station frequencies start from 153 + Nx9 kHz, and this radio is shifted with 2kHz, and originally are made in this way. In all specifications and catalogs are written for this radio LW band 146-353 kHz. I did not know why at tuners made before 1985 the LW band is shifted (Akai, Rotel, ...).
Accumulator was out of order (3.6V 30mAh NiCd type, made by Yuasa, Japan) - was necessary to be replaced. To be remarked: after more, than 40 years operation no any surge or oxidation mark on it! Same as all 470uF/6.3V capacitors in control board (measured capacitance was 291uF!). Basically all electrolytics were changed.
In general, the Dual use low coupling capacitors values in its equipment between audio stages, is better to be changed into higher values.



Fisher


Fisher Electronics was an American audio equipment manufacturer founded in 1945 by Avery Fisher in New York City, New York. Originally named the Fisher Radio Corporation, the company is considered a pioneer in high fidelity audio equipment. Fisher initially developed, manufactured, and marketed high-performance audio products under the trade name "The Fisher". In February 1969, Emerson Electric announced plans to purchase Fisher Radio. The purchase was completed later that year. Emerson subsequently sold Fisher to Sanyo Electric of Japan in 1975, where it remained until 2010 when Sanyo was purchased by Panasonic, but the Fisher brand was phased out owing to the termination of Sanyo by Panasonic in 2012. Fisher's product lineup was eventually re-branded as Panasonic.


Fisher Studio - Standard FM-2310


Fisher FM-2310

This is one of Fisher's last high-end designs for an AM-FM stereo tuner and was a serious competitor of Marantz brand. The tuner part is similar to what can be found in Fisher's top receiver, the RS-1080. Has an aluminum face panel with simple markings, 3 meters: signal level, the center of channel tuning, and deviation/multipath (switchable) on the front panel. The FM Deviation / Multipath Meter is very unique, different and definitely, I don't see on any other manufacturers. The dial is somewhat reduced in length due to the inclusion of the meters, but still easy to read. Inside has two circuit boards, one for the power supply (which includes the Deviation/Multipath circuitry) and one for the AM-FM IF MPX and audio circuits. The FM RF circuitry is in a separate shielded box along with the AM RF/Osc/Mixer tuning circuits. Has an FM front end with DGMOSFET RF amplifier stage, separate mixer, and oscillator circuits and a 5-gang mechanical tuning capacitor. It has a total of 4 ceramic IF filters (all of which are plugged into sockets) that are all 280kHz bandwidth. Since the 3-leg filters plugin, they can easily be changed to narrower bandwidth filters if desired for DX work. The LA1230 quadrature detector and LA3350 MPX ICs are also factory socket-mounted!

General information:

  • Manufactured at 1977 by Fisher (Sanyo) in Japan
  • 2 band analog superheterodyne receiver, MW and FM
  • Coverage: MW 525kHz - 1.605MHz, FM 88.0MHz - 108.0MHz
  • Antenna input impedance for FM: 300 ohms balanced and 75 ohms unbalanced,
  • No preset memory for FM
  • Usable sensitivity: 1.7 uV on FM mono and 4.3 uV (!) for stereo; 280uV/m on AM
  • Intermediate frequencies: 455kHz for AM, and 10.7MHz for FM
  • Used ICs: FM IF amplifier LA1222; FM IF detector LA1230; MPX decoder LA3350; AM IF detector HA1138; output amplifier and deviaton/multipath LA3122
  • Signal to noise ratio: mono 80dB, stereo 75dB for FM
  • Harmonic distortion: mono 0.10%, stereo 0.15% for FM
  • Output frequency range on FM: 20Hz - 15kHz (+0.5...-1.5dB)
  • Stereo separation (1kHz/10kHz): 50/36 dB
  • Power: 110V/220V 50Hz, consumption 16W
  • Dimensions: 440x140x315 mm, 10.5 kg.
Good things:
  • Has a very clean sound with bright bass, low noise, good channel separation
  • Has a separate operational amplifier IC (LA3122) at output instead of direct signal from MPX IC
  • Very good sensitivity on FM
  • Has an extra meter for deviation and multipath: deviation act almost as a VU meter, and multipath makes it possible to adjust the tuner more precisely on station (when shows 0%)
  • Has an additional adjustable output, adjusted from the front panel
  • High Blend function: during the reception of stereo broadcast, noise possibility caused in both channels are reversed in phase to each other. With high-blend switched on, the separation in the audio high-frequency band becomes a little decreased.
  • Air check calibration circuit: this circuit is to make appropriate the recording level in advance when recording FM broadcast into the tape recorder. This circuit is an RC type oscillator to be used for air check calibration with approximately 400Hz frequency. In the case of AM signal, the air check calibration is not functioning.
Difficult, problematic items:
  • Lower scale width regarding 3 meters on front
  • Has 4 pcs 280kHz wide-bandwidth ceramic filters (in sockets!) - is recommended to be changed with low loss 150kHz models, all carefully paired.
With more than 40 years, is one of the best sounding FM tuner that I have. Was necessary to change all electrolytic capacitors. Unfortunately on my set, the ferrite antenna is missing, I cannot test the AM. Probably, when I will have more time, I will make one (I know, will never be the same as the original).
Its sensibility outperforms some tuner with better specifications.
It retailed for about $250 back in 1977, which in today's dollars is roughly $890!



General Radio Co.


On June 14, 1915, a small group of investors started General Radio Company in Cambridge, Massachusetts, near Massachusetts Institute of Technology. During the 1950s, the company moved to West Concord, Massachusetts, where it became a major player in the automatic test equipment (ATE) business. It also produced extensive lines of electrical component measuring equipment, sound and vibration measurement and RLC standards. In 1975, the company name was changed to GenRad. In 1991, a startup QuadTech was founded as spinoff of GenRad's Instrumentation division and Precision Product lines, as well as the rights to use the "GenRad" and "General Radio" names. In 2000, IET Labs aquired QuadTech.


419-A Rectifier Type Wave Meter

419-A Rectifier Type Wave Meter

The oldest piece of my "museum" is not exactly a receiver, just the method used in it is similar, is a detector radio used for frequency measurement.

General information:

  • Manufactured at 1929 by General Radio Co., Cambridge A, Massachusetts
  • Measurement method: absorbtion - placed in vicinity of source
  • 4 ranges with 4 interchangeable inductors: 20-40MHz, 40-75MHz, 75-150MHz and 150-300MHz - all based on amplitude modulation.
  • Calibration: 4 separate charts given for each range/inductor.
  • Accuracy: within 1%
  • Rectifier: one RCA 1G4-G triode, with 1-1.2V/40mA filament voltage (from battery)
  • Power supply: 1.5V A type battery
  • Serial number: 211
Condition: the tube is out of order, now without any modification in tube socket are inserted one Schottky diode and operates well (cannot be received radio programs, tested just via AM signal generator).



Grundig


Grundig began in 1945 with the establishment of a store named Fürth, Grundig & Wurzer (RVF), which sold radios and was headquartered in Fürth, northern Bavaria. After the Second World War, Max Grundig recognized the need for radios in Germany, and in 1947 produced a kit, while a factory and administration center was built at Fürth. In 1951, the first television sets were manufactured at the new facility. At the time Grundig was the largest radio manufacturer in Europe. It grew to become one of the leading radio, TV, recorder, and other electronics goods manufacturers of Europe in the following decades of the 20 century. In the 1970s, Philips began acquiring Grundig AG's shares, leading to complete control in 1993. In 1998, Philips divested Grundig. In 2007, Koç Holding bought Grundig and put the brand under its home appliances subsidiary Arcelik A.S.


Grundig YB-P 2000

Grundig YB-P 2000

The timeless elegance of this radio was inspired by the legendary Porsche 911, exhibits the same purity of line that has made the 911, a timeless classic. The genuine leather case embodies the meticulously crafted control panel with its smooth, recessed speaker grille and deeply sculptured buttons that highlight this design. Has scan and manual tuning, preset-memories, direct keypad entry, dual-alarm clock, sleep timer, headphone connection, etc., like an ideal traveling partner.

General information:

  • Manufactured between 1997-98 by Grundig in Portugal (that time part of Philips)
  • 4 bands: FM 87.5 - 108 MHz, MW 520 - 1710 kHz with 10kHz steps for America, and 522 - 1620 kHz for the rest of the World, SW1 2.30 - 7.40 MHz and SW2 9.40 - 26.10 MHz, in total 13 SW bands
  • Shortwave bands by lengths for SW1 (6 bands):
    • 120m: 2300 - 2550 kHz
    • 90m: 3150 - 3450 kHz
    • 75m: 3850 - 4050 kHz
    • 60m: 4700 - 5150 kHz
    • 49m: 5750 - 6300 kHz
    • 41m: 7050 - 7400 kHz
  • Shortwave bands by lengths for SW2 (7 bands):
    • 31m: 9400 - 10050 kHz
    • 25m: 11500 - 12200 kHz
    • 22m: 13500 - 13900 kHz
    • 19m: 14950 - 15700 kHz
    • 16m: 17400 - 18000 kHz
    • 13m: 21300 - 21950 kHz
    • 11m: 25600 - 26100 kHz
  • Tuning steps: FM: 50kHz, MW 9/10 kHz, SW 5kHz
  • Preset memory: in total 20 - 5 for FM and, 5-5 for AM (5 for MW, 5 for SW1, and 5 for SW2)
  • Intermediate frequencies: for FM 10.7MHz, for AM 450kHz
  • Antennas: for FM and SW a telescopic aerial, for AM a built-in ferrite rod
  • Output power: 250mW
  • Stereo: just via headphones (the impedance of delivered headphone was 32 ohms)
  • Power supply: 4.5V by 3 pcs of AA type batteries or 4.5V DC external power supply
  • External dimensions: 142 x 92 x 35 mm (WxHxD)
  • Weight: 330 g
  • No more technical parameters are available about this radio
  • Good things:

    • Very beautiful design, easy operation, all buttons deepened, but easy to be pushed
    • Nice snap-on leader case. When is closed, the speaker, the antenna, and the power button are free. The case can be folded back and became a support for the tilted radio
    • Direct digital keypad tuning
    • Can be selected the required SW band by name of band wavelength/meter
    • Has a Lock switch, protecting during travel or by mistake and powering on

    Difficult, problematic items:

    • Low preset memory, just 5-5 locations for FM, MW, SW1, and SW2
    • No continuous tuning, in Continuous mode the radio jumping from the end of the band to the next band's beginning, means the SW band is continuous
    • The display lamp is activated just till the Lamp button is pressed, no temporization
    • The selectivity on FM is good, on MW is acceptable (internally has a very small ferrite rod), but on the SW band is very low
    • In AM mode has just a single conversion IF, which means on the AM the reception is very noisy
    • The tuned indicator on the display shows just the radio is tuned to the station frequency, if we are near, no help in which direction we should go

    This radio has very good marketing in its time, in several magazines with high reputation was named World Receiver, but the radio part is very weak, I did not recommend it to any DX activity. Still, the Sony ICF-SW11 is much better, which is also a single IF radio. In some radioamateur portals are highlighted its poor SW reception capability - and this is true.
    This radio later was produced by Eton Co. as Grundig G2000A - is a completely same radio.
    Modifications: over 20 years, and because the used capacitors are low voltage types, their degradation level require to be changed. I recommend solid electrolytic capacitors (or tantalum in the RF part). In position C47 instead of 470uF/10V I soldered 1000uF/6.3V OSCON type, C12 instead 22uF received 47uF, C52 was changed from 22uF to 100uF, and C51 from 100uF to 220uF, the rest of the capacitors were changed with the same values.
    The keyboard rubber is fixed to PCB very ingeniously - via small rubber legs, which need to be inserted in PCB to keep their position. For reinsertion you can use component legs, pushing the wire from the opposite side of the rubber into the hole on the PCB - and for this, the legs have a cylindrical hole made for this purpose! Another thing that impressed me was the output capacitor value and is the same for both channels: 470uF/10V, which gives a nice color for music especially via headphones. Sales price in 1998 was 220 DM.



Harman Kardon


In the early 1950s, Sidney Harman was the general manager of the David Bogen Company, a manufacturer of public address systems at the time. Bernard Kardon was the chief engineer at Bogen. Due to management changes at Bogen in the early 1950s, both men resigned, and Sidney Harman and Bernard Kardon founded the Harman Kardon Company in 1953. By 1956, Bernard Kardon decided to retire and sold his interest in the company to Sidney Harman. As the sole head of Harman Kardon, Harman continued to make the company a technical leader in Hi-Fi products. Sidney Harman would change the company's name to Harman International, but the receivers, tuners and amplifiers were still branded Harman Kardon. The products continue to be branded as Harman Kardon to the present day. In 1969 Harman bought the major speaker manufacturer JBL. Harman Kardon's design goal is to have the highest possible design quality for the price, rather than unnecessary features. On March 11, 2017, Samsung Electronics announced the acquisition of Harman.


Harman Kardon TU-9600

Harman Kardon TU-9600

Was the flagship of Harman Kardon's tuner series in 1991. Has a very good sensitivity on FM, with a very good station separation due to "Active Tracking" circuitry and "Digital Fine Tuning".

General information:

  • Manufactured by Harman Kardon in USA at 1991
  • Digital 2 bands (MW-FM) PLL radio,
  • 24 memory presets, which can be mixed between AM and FM
  • Coverage: MW 520kHz - 1.710MHz, FM 87.5MHz - 108.0MHz
  • Usable sensitivity: 20uV on AM, 1.0uV on FM (mono) and 17.7uV for stereo - via a very sensitive JFET FM tuner
  • FM IF IC: LA1235, AM tuner IC: LA1245, stereo decoder: LA3450, PLL with prescaller: TC9227P, uController: TC9301AN, interface for I/O port: TC9173P, LED driver for signal strength: BA6124, FL tube display driver: TB2104F
  • Output frequency range: 20Hz - 15kHz (-1...+0.5dB)
  • Signal/noise ratio: AM 53dB, FM 82dB mono, 78dB stereo
  • THD: on FM 0.06% for mono, and 0.08% for stereo
  • Stereo separation: 50dB
  • Alternate Channel Selectivity (FM): 80dB with Active tracking mode
  • Adjacent Channel Selectivity: on FM 30dB with Active tracking mode, on AM 55dB
  • Line output impedance: 10 kohm
  • Line output levels: 440mV in AM mode, 1.1 V in FM mode
  • Antenna input impedance for FM: 75 ohms for both. Selection of input via relay
  • Power: 230V/50Hz, Consumption: 9W
  • Dimensions: 443x73x328mm, 3.4kg

Good things:

  • Has a very clean sound, low noise, good channel separation, good readable FL display, and good "Active Tracking" which has a function of "narrow" IF.
  • Has 2 FM antenna inputs, selectable from the front panel
  • Discrete output amplifier instead of an operational amplifier IC
  • Is impressive the quality of electrical parts used, especially in case of solid capacitors

Difficult, problematic items:

  • Memory is organized like 3 x 8 = 24 positions (A:1-8, B:1-8, C:1-8). Should be more natural 3x10 = 30.
  • Has no RDS (in 1991 was not so common).
  • In the case of tracking/fine-tuning, the display does not show the base frequency modification in numbers, just with arrows in +/-2 marks.
Active Tracking/Fine Tuning: these features are designed to reduce signal interference that can occur when we tune into a weak FM station adjacent to a stronger station. With Fine Tunning, we can shift the receiving frequency away from the stronger station.
Generally: is a very good tuner for high-quality FM DX audio program listening with 2 selectable antenna inputs.



Hitachi


Hitachi is a Japanese multinational conglomerate in Chiyoda, Tokyo, Japan. Was founded in 1910 by electrical engineer Namihei Odara in Hitachi, Ibaraki Prefecture. The first products were 4kW inductor motors used in copper mining. Odaira moved headquarters to Tokyo in 1918. Odaira coined the company's toponymic name by superimposing two kanji characters: hi meaning "sun" and tachi meaning "rise". World War II had a significant impact on the company with many of its factories being destroyed by Allied bombing raids, and discord after the war. At 1958 made its first 6-transistor miniature portable radio. From 1968 start its semiconductor business with LSI hybrid ICs. 1969 color TV sets, from 1984 256kbit DRAM production, 1987 large color LCD displays, in 1990 TFT color LCD display, 1994 32bit RISC processor family and 1Gbit DRAM, 1997 4.7Gbyte DVD-RAM,...


Hitachi FT-3500

Hitachi FT-3500

Is a very fine slimline tuner from the bottom line of Hitachi (middle line from that era was the FT-4500 and FT-5500, but both are with a digital scale, better distortion and SN factors, but same sensibility - 1.0uV on FM; and the top tuner was the FT-8000). Based on advertisements from its era "has a very advanced Hitachi electronics, ..., and has a three-LED vector-tuning cursor to ensure accurate alignment to transmitter frequencies,...". This means the tunning indicator is on the cursor, and the lateral LED from both sides and their intensity helps the user to center the frequency exactly on the radio station used one. The power switch illuminates when the unit is operating.

General information:

  • Manufactured by Hitachi Ltd., Tokyo, Japan at 1981
  • Analog 2 bands (MW-FM) superheterodyne radio (FT-3500L are with 3 bands, including the LW),
  • No memory presets
  • Coverage: MW 530kHz - 1.605MHz, FM 88.0MHz - 108.0MHz
  • Usable sensitivity: 15uV on MW and 1.0uV on FM mono and 23uV for FM stereo - via a very sensitive MOSFET FM tuner
  • FM IF IC: HA12412, AM tuner IC and IF amplifier: AN217, stereo decoder: HA1196
  • Output frequency range: 20Hz - 12kHz (+2.0dB...-2.0dB)
  • Signal/noise ratio: FM 77dB for mono, 70dB for stereo
  • THD: on FM 0.1% for mono, and 0.25% for stereo
  • Stereo separation: 45dB
  • Alternate Channel Selectivity (FM): 50dB
  • Line output impedance and level: 6.8 kohm/550mV
  • Antenna input impedance for FM: 75 ohms unbalanced or 300 ohms balanced
  • Power: 220-240V 50/60Hz, Consumption: 6W
  • Dimensions: 4435x83x253mm (WxHxD), 3.4kg

Good things:

  • Good sensibility on FM, clean sound, low noise
  • The scale is shown by a rectangular red LED
  • Very easy operation

Difficult, problematic items:

  • No signal strenght indicator, just the 2 lateral LEDs light intensity can be used from the cursor
  • The output frequency range seems to be narrow, just 30-12kHz with high deviation, but the sound is pleasant
  • Has no scale light, which means in dark you cannot see where are you on the scale
When I bought it as a defective one, the R802 resistor was burned, instead of 39 ohms resistance its value was 1027 ohm. After changing it the radio wakes up. The tuner's ceramic filetrs are with blue dot, means their senter frequency is 10.67MHz with 230kHz bandwidth. The power button bulb was changed with warm white LED (with 1.5kohm + 1N4148 connected to 24Vac). C315/C316 changed with 4.7uF/63V polypropylene foil caps. In the power line, C803 changed to 1000uF/50V, C301 and C804 with 470uF/35V. Rest of electrolytes with same values, below 4.7uF with foil capacitors.
The power line received an EMI filter: 2.2nF/3kV + 2x35mH noise suppressor coil and 1uF/500V PP capacitor.



JVC


The Japan Victor Company, is a Japanese international professional and consumer electronics corporation based in Yokohama. Founded in 1927, the company is best known for introducing Japan's first televisions and for developing the Video Home System (VHS) video recorder. From 1953 to 2008, the Matsushita Electric Industrial Co. was the majority stockholder in JVC. In 2008, JVC merged with Kenwood Corporation to create JVCKenwood. JVC sold their electronic products in their home market of Japan under the "Victor" name with the His Master's Voice logo, but used the name JVC or Nivico (for "Nippon Victor Company") in the past for export due to differing ownership of the His Master's Voice logo and the ownership of the "Victor" name from successors of the Victor Talking Machine Company. In 2011, the Victor brand for electronics in Japan was replaced by the global JVC brand. However, the previous "Victor" name and logo is retained by JVC Kenwood Victor Entertainment, and is used as JVCKenwood's luxury HiFi marque.


JVC T-X1L

JVC T-X1L

General information:

  • Manufactured at 1980 by JVC - Victor Company of Japan Ltd. at Yokohama
  • 3 band analog superheterodyne tuner LW, MW and FM
  • Coverage: LW 150 kHz - 360 kHz, MW 520kHz - 1.710MHz, FM 87.5MHz - 108.0MHz
  • Antenna input impedance for FM: 300 ohms balanced, 75 ohms unbalanced,
  • No preset memory for FM
  • Usable sensitivity: 80uV on LW (external aerial), 50uV on MW (ferrite bar), 0.9 uV on FM mono and 22.5 uV for FM stereo
  • Intermediate frequencies: 450kHz for AM, and 10.7MHz (exactly 10.67MHz, blue marked filter) for FM
  • AM/FM ICs: HA1197 AM tuner IC, HA11225 FM IF system, uPC1161C MPX decoder IC and LB1416S as a signal indicator.
  • Output frequency range: 40Hz - 15kHz (-0.5...+0.5dB)
  • Power: ~220V/50Hz, consumption 12W
  • Output power: 600mV/3.3kohm
  • Dimensions: 420x108x313mm, 4 kg.
Is an old, good tuner with a warm sound, selectivity is very good, and can drive directly my 600 ohm headphones without any problem.
Is very interesting the scale: can be seen just the selected band ones. Consist of two transparent plexiglass with engraved scale, one for FM and one for AM (MW and LW) and are separately lighted just the used one. From the exterior can be seen just one scale, just the selected/lighted one (like on the picture).
Just some out of order electrolytic capacitors were changed in the power line.


JVC T-K10L

JVC T-K10L

Is a low end tuner with surprisingly good sensitivity and sound. Cannot be found much information on the net about this model. Its upper model is the T-K20/L.

General information:

  • Manufactured between 1982 - 1984 by Victor Company of Japan
  • 3 band analog PLL tuner LW, MW, and FM
  • Coverage: LW 150 - 350 kHz, MW 525 - 1605 kHz, FM 88 - 108 MHz
  • Antenna input impedance for FM: 300 ohms balanced, 75 ohms unbalanced,
  • No preset memory for FM
  • Usable sensitivity: 30uV on MW, 100uV on LW, and 0.9 uV on FM (mono) and 44 uV for stereo
  • Intermediate frequencies: 450kHz for AM, and 10.7MHz for FM
  • AM tuner IC: LA1245 amp, osc, IF and det; FM det. HA1137W; stereo decoder (MPX) uPC1161C3; signal indicator LB1416
  • Output frequency range: 30Hz - 15kHz (+0.5dB...-0.8dB)
  • Signal/noise ratio: AM 50 dB, FM 74dB mono, 67dB stereo
  • THD: 0.2% in FM mono, and 0.3% in stereo at 1kHz; 0.3% on AM
  • Stereo separation: 37dB at 1kHz
  • Channel balance: no data
  • Power: ~220V/50Hz, consumption 7W
  • Output power: 800mV/3.3kohm
  • Dimensions: 435(W) x 77(H) x 299mm (D), 2.9 kg.
Some resistors are printed on the board, and this is the weakness of this tuner. I buy it for 10$ as defective with a very low output audio level, and the problem was one of such resistors.
The sensibility and the stereo signal capturing outperform the specification - means at very low signal level still can receive the stereo transmission without any sizzling noise.
The scale has no backlight, just the cursor, which is made from a wide transparent plexiglass and is illuminted by bulbs separately: for AM with very light green, for FM with very light blue lights (now the miniature bulbs were changed with warm white miniature LEDs, using the coloured rubber caps from miniature bulbs).
The power transformer are constantly connected to line without fuse, and the power switch connect the low voltage to tuner. During long operation the transformer remains cool. Received an EMI filter at power line input.
The RC network (10kohms in serial connection with 10uF) are not mounted on pins 4 and 5 of MPX decoder (uPC1161C3), the audio signal goes trough a low pass and band stop filter (set for 37.5kHz).



Kenwood


The company was established in 1946 as the Kasuga Radio Co. Ltd. in Komagane City, Nagano Prefecture, Japan. In 1960, the company was renamed Trio Corporation. An importer of Japanese-made electronics, A&A Trading Co for RadioShack, and a manager from there, William "Bill" Kasuga partnered with George Aratani and Yoichi Nakase decided to establish a company that would be the exclusive importer of Trio products. The name Kenwood was invented by Kasuga as being the combination of "Ken", a common name in Japan and North America that had been tested and proven acceptable to American consumers in the name of Kenmore appliances, and "Wood", referring to the durable substance as well as suggesting a relation to Hollywood, California. The brand recognition of Kenwood eventually surpassed that of Trio, and in 1986 Trio bought Kenwood and renamed itself Kenwood. George Aratani was the first chairman of Kenwood USA Corporation and succeeded by Kasuga. In October 2008, Kenwood merged with JVC to form a new holding company, named as JVCKenwood.


Kenwood KT-815

Kenwood KT-815

This tuner has a Trio trademark: the Pulse-Count Detector. In an FM tuner the conversion of frequency modulation into the original audio signal takes place in a detector that is fundamentally immune to distortion and practically ignores noise. Has IF selectivity switch: Wide and Narrow; MPX filter switch on/off possibility; Auto/mono mode selection; Servo lock/Muting switch on/off. It has servo lock tuning for drift-free RF performance, and de-emphasis (50/75uS) switch on rear cover.

General information:

  • Manufactured at 1979-1981 by Trio-Kenwood Co., Meguro-ki, Tokyo, Japan
  • 2 band analog superheterodyne tuner, MW and FM
  • Coverage: MW 510kHz - 1.640MHz, FM 87.5MHz - 108.0MHz
  • Antenna input impedance for FM: 300 ohms balanced and 75 ohms unbalanced,
  • No preset memory for FM and AM
  • Usable sensitivity: 0.8 uV on FM mono, 25uV on FM stereo; 9uV on AM
  • Intermediate frequencies: 455kHz for AM, and 10.68MHz
  • Used ICs: AM tuner HA1197, FM IF amplifier LA1222 and TA7060P, FM IF system HA1137, balanced modulator MC1496, pulse count detector TR4010A, PLL stereo demodulator HA11223W, op. amplifiers HA1457.
  • Signal to noise ratio: mono 84dB, stereo 80dB for FM, and 55dB for AM
  • Harmonic distortion: mono 0.05%, stereo 0.07% for FM, and 0.5% for AM
  • Output frequency range: 30Hz - 15kHz (-0.3...-0-5dB)
  • Power: ~110-120/220-240V/50Hz, consumption 20W
  • Output: fix 0.75V/2.5kohm or variable 0-1.3V/1.5kohms; multipath output: vertical 0.02V/1kohm and horizontal 0.35V/10kohm
  • Dimensions: 440x153x402mm, 7.6 kg.

Good things:

  • Extremely clear sound
  • High sensibility and selectivity on FM, but also the AM is very good
  • Nice adjustment using the 2 instruments
  • Variable output signal level, adjusted from front panel

Problematic things:

  • Instruments ilumination is very weak
  • Leack of bass
  • No any data can be found about TR4010A pulse count circuit, made for Trio-Kenwood
Is same as KT-8155 model.

Modifications
General: all electrolytic capacitors were changed with new ones, and from below 4.7uF with foil-type (mostly WIMA), rarely with TA. Originaly the power cord was for 110Vac network, I changet it.
This radio on several portals is mentioned as "the KT-815 is capable of excellent RF performance but its sound quality has been criticized for being "thin" and "too dry". For that reason, mostly based on Tuner Information Center recommendation, I implement some modifications in the signal path and power supply, and the result is impressive! I highly recommend it to every owner!
Power supply (mentioned just those components, which value were changed): C15, C28, C46, C47, C49, C55, C63 47uF->100uF/63V Rubycon; C33 33uF/16V->100uF/63V Rubycon; C64 470uF/16V->1000uF/35V; C106, C107, C112, C113 1000uF/25V->2200uF/25V Rubycon; C78 220uF->1000uF/35V Rubycon; C92, C102, C103 47uF/16V->470uF/35V Nichicon; C99 33uF/16V->470uF/35V Nichicon; C108 100uF/25V->470uF/35V Nichicon; C110 100uF/10V->390uF/35V Rubycon; C23 200uF/16V->390uF/35V Rubycon. D29 RB-151 changed to 4 pcs UF4007 diodes. R170 100 ohms received in serie one 2.2uH coil. In power section any high value capacitor received in parallel a 0.22-0.33uF/50V MKT. Mounted an AC filter after power cord (2.2nF/3kV + 2x7.8mH + 1uF/500V, but the 1uF was mounted after power switch).
Signal: C95, C96 10uF/16V->100uF/35V Nichicon Fine Gold; C100, C101 3.3uF/50V-> 10uF/63V MFT ROE; C104, C105 10uF/16V-> 22uF/100V MKT Vishay; C90, C91 0.22uF/50V->1uF/63V MPT; C72 270pF ceramic changed to same value PP; C77 0.047uF-> 0.47uF/50V MKT Wima; C84 received in parallel a 39pF NPO type.
Other recommended changes (not made yet): FM IF ceramic filters to be changed to low loss and narrow ones (ex. +-150kHz). Must be noted: all ceramic filters are blue dot type, which means 10.68MHz, not 10.7MHz! The output operational amplifiers is recommended to be changed with modern low noise types (MC34081, OPA2604, OPA2132 or AD845 are recommended, and can be tested other types), but a SIP8 to DIP8 adaptor is required (I made myself). Is also recommended to be changed the power line path, or take out the balun transformers at the FM antena input (this can increase the sensibility with +3dB), or take out the FL6 and FL7 filters from the audio output.
In general, is a remarkably good tuner with a lot of upgrade possibilities!



Kenwood KT-80

Kenwood KT-80

As part of the slim-line series, was designed for KA-80 High Speed DC integrated amplifier. Is just an FM tuner with a servo-lock which eliminates the need for a tunning meter, based on Kenwood advertisement from '80. The signal level meter is made with 5 LEDs. Use the Kenwoods Pulse Count Detector, which virtually banishes FM noise and half the distortion. Has a Record Calibration Control for studio-quality off-the-air recordings, and an exceptional signal to noise ratio: in mono is 83dB, and 80dB for stereo mode.

General information:

  • Manufactured by Trio-Kenwood Corp., in Japan between 1980-82
  • Analog, just FM band tuner with 4 gangs
  • No memory presets
  • Coverage: 87.5MHz - 108.0MHz
  • Usable sensitivity on 75ohm antenna input: 0,6uV on FM mono and 22uV for FM stereo
  • Used ICs (in total 9): SC114 as an oscillator and mixed in tuner section; TA7060 opamp as IF signal amplifier; HA1137W as FM IF system; AN610 balanced modulator circuit; TR4010A pulse count detector; AN6135 pop-noise canceller; HA12016 FM MPX decoder, AN6551 opamp as record signal calibrator and AFC; M51903L as signal level indicator for LEDs.
  • Output frequency range: 30Hz - 15kHz (+0.2dB...-0.8dB)
  • Signal/noise ratio: FM mono 83dB, FM stereo 80dB
  • THD: on FM 0.07% for mono, and 0.12% for stereo
  • Stereo separation: 47dB
  • Channel balance: 1.5dB
  • Alternate Channel Selectivity (FM): 75dB
  • Line output impedance and level: 3.3 kohms/300mV
  • Antenna input impedance for FM: 75 ohms or 300 ohms
  • Power: 220V/50Hz, Consumption: 11W
  • Dimensions: 440x78x333mm, 4.5kg

Good things:

  • Very clean sound with low distortion, and has a high signal to noise level ratio (thank to pulse count detector)
  • Good sensibility
  • Two 75ohms antenna inputs: for coaxial cable and wire
  • Has a Postdetection Filter to eliminate HD FM radio noise (used in America)

Difficult, problematic items:

  • No tunning meter, just the servo lock - in the case of stations with low a signal is difficult to adjust using just one Tuned/Lock LED as feedback.
  • The scale is not so easy to read in the dark
  • No narrow/wide IF filter selector
Was available also in black, marked as KT-80B. The FM sections are similar to the earlier KT-615 and later KT-900 models, being simplified the FM tuner part. The IF path (almost the same as KT900) uses a total of three 3-pin ceramic filters with IF amps (discrete and TA7060P) in between, with two different (presumably matched) filter sets: SFE10.7M (+-230kHz) and two SFE10.7MS3 (+-180kHz).
In some forums are mentioned changes to improve the sound shortening its path on the PCB or components: taking out the calibration tone generator, and the signal can go from C40 to C33 using one capacitor, or taking out the R39-R40, C51-C52 (bypassing the last 2), etc.

Modifications:
All electrolytic capacitors changed. Below 4.7uF anywhere, and below 10uF in the signal path with foil capacitors. In the next will be mentioned were I changed or added new components.
Power path: C13, C57, C66 were replaced with 100uF/63V Nichicon, C83 with 2200uF/25V Rubycon, C63, C86 and C88 all replaced with 390uF/35V Rubycon, C27 and C74 replaced with 1000uF/35V Rubycon. Jumper J9 was replaced with a 220ohms resistor (is the power line of IC3/AN610), and in paralel with C16 was mounted a 270uF/16V OSCON with 100pF. On power transformer primer coil after power switch received in parallel one 470nF/275Vac pp, and on secondary, on both outputs one-one 470nF/275Vac pp foil capacitors.
Signal path: C22, C29 and C31 instead of 0.047uF all were replaces with 1uF/63V pp, C35 changed to 47nF/100V pp, C34 received in parallel 47pF C0G MLCC, between pin 5-6 of HA12016 one 100pF C0G. R18 changed from 1.8kohms to 1kohms. In parallel with C38 on pin 12 of HA12016 inserted one 10nF C0G, same with C61 on pin 13 of HA1137W received 10nF C0G. C39 replaced with 2.2uF/63V pp. C41 and C42 were replaced with the same value, 47uF/63V Nichicon Fine Gold type. R39-R40 changed from 3.3kohms to 5.6kohms. Basis of changes - Kenwood KT-L01T model.
The VCO of HA12016 is difficult to adjust, can be measured the 76kHz signal just between VR1 and R28. After changing all electrolytes needs to be readjusted.
On the PCB of the tuner, around HA12016 can be found the positions of components for 75us de-emphasis, but are omitted including with de-emphasis selection switch in my European version. The most often linked service manual on the net has an error: the output audio signal comes from the negative input of the output buffer amplifier of IC5/HA12016, but correctly comes out from the real output - pins 4 and 7.
Upgrade: (idea implemented from KT-615) at the gate of Q1 R1 instead of direct ground connection is better to be connected to ground via 10kohms, and this point to be connected to the power supply via one 470kohms resistor. This will increase a bit the sensibility of the tuner.
With improved capacitors in the signal path, improved power lines and all other modifications result is a detailed and clear sound.


Kenwood Basic T2

Technics ST-G5

Is the successor of the Basic T1 tuner, equipped with Direct Linear Loop Detector (DLLD) which gives ultra-low distortion for FM detection with distortion correcting circuit, achieving 0.0095% FM THD at 1kHz in wide IF mode. The T2 appears to be the first Kenwood tuner to use the DLLD. Has an advanced low-noise synthesizer circuit with high interference rejection, wide/narrow IF band selector, automatic seek tuning up or down, 8 FM and 8 AM preset memory, 2 stations automatic pre-program memory, and a special circuit: variable AM IF band control to optimized AM broadcast.
In Japan was sold as Kenwood KT-1010 II or under the brand name Trio KT-1010.

General information:

  • Manufactured by Trio-Kenwood Corporation in Japan between 1984-1985
  • Digital 2 bands (MW-FM) PLL radio,
  • 16 memory presets:8 for FM and 8 for AM
  • Coverage: MW 522kHz - 1.611MHz; FM 87.5MHz - 108.0MHz
  • Adjusting steps: MW 9 kHz; FM 50 kHz for EU version
  • Usable sensitivity: 10uV on MW, 0.7uV (in some catalogs 0.95uV) on FM mono and 28uV for FM stereo
  • FM IF system IC: LA1231NS; AM tuner IC: LA1245; MPX decoder uPC1223C; Prescaler: TD6104P; PLL controller TC9157P; FL display driver: TD6301AP; FM IF ampifier: uPC1163H; pop-noise canceller AN6135; signal level LED driver AN6882; analog multiplier NJM4200D; operational amplifiers NJM4558D, NJM45600-N; stabilizator uPC78M05H
  • Output frequency range: 20Hz - 15kHz (0.0dB...-+0.5dB)
  • Signal/noise ratio: AM 52dB, FM 88dB mono, 76dB stereo
  • THD: on FM in Wide mode 0.004% for mono and 0.008% for stereo, and in narrow mode 0.02% for mono, and 0.04% for stereo at 1 kHz
  • Stereo separation: 55dB on audio band (50 Hz ... 10kHz), and 70 dB at 1 kHz
  • Line output level: on FM 0.6V/ 1.8kohms, on AM 180 mV/ 1.8kohms
  • Antenna input impedance for FM: 75 ohms unbalanced
  • Power: 120/220V 50/60Hz (selectable at plug-in cable with a cover), Consumption: 19 W
  • Dimensions: 440x64x317mm, 3.8kg

Good things:

  • High-quality electrical parts used
  • Very good selectivity and sensitivity on AM (10uV), excellent AM section, very immune to interference/static
  • Variable AM IF band control
  • Dual transformer for circuits isolation
  • Very low distortion on FM (0.004% in stereo wide mode), good stereo separation (68dB) and high signal/noise ratio (88dB)
  • Has a Postdetection Filter to eliminate HD FM radio noise (used in America)

Difficult, problematic items:

  • In stereo mode, once the stereo signal is lost, the unit automatically mutes the audio instead of defaulting to mono which can be annoying.
  • In AM mode is better if you switch to Mono mode (no mute), because the station sound intermittently is broken in case of the weak signal.
I have the Europen version - means is not mounted the AM step selector (CN3 connector and the S18 switch), and the deemphasis circuit is missing (CN11 connector, the selector switch S17 and C107/C108 capacitors for 75us). Capacitors were in the wrong shape (almost 40 years old), and I changed all electrolytics. In the case of used ones in the sound signal path into pp (till 10uF), the rest with high-quality electrolitics, and received an EMI filter at AC input.
The frequency display is shifted with 50kHz, I did not found how can be adjusted correctly, but with this deviation, the signal is on max value, the stereo decoder works correctly. At AM the sensibility is exceptional: I have never seen such sensibility with the loop antenna, no ferrite bar inside.
The original price was 798DM at 1984.
Modificationons:
Basically, because is a well-made tuner, just the power line can be improved. Compared to all datasheets of used ICs, just one significant item I found: the pin 18 of uPC1223 stereo decoder is decoupled with 820pF to the ground.
Modification of power lines: C27, C95 1000uF/35V; C60, C85, C91, C113, C151, C154, C177, C184 390uF/35V; C73, C89, C95, C110, C119, C161, C163, C169, C173 100uF/63V; C146 2200uF/25V; C159 560uF/35V. Additionally was inserted coils in power lines, to decrease the noise between units: in tuner section, J145 jumper was replaced with 10uH/0.2 ohm coil; in IF demodulator section, with R54 in series was inserted 22uH/0.3 ohm coil; in stereo demodulator section, J68 was replaced with 47uH/0.6 ohm; in the power circuit of PLL controller J172 jumper was replaced with 10uH/0.2 ohm.


Kenwood KT-880DL

Kenwood KT-880DL

Is a quartz-synthesizer 3 band stereo tuner with DLRC (Direct Linear Reception Circuit), Pentacle Power System, Computer controlled tuning system, automatic tuning, and FM IF-bandwidth selector. Has a 20 stations random access preset memory and a large FL display. Is very sensitive, in some catalogs are mentioned 0.7uV as FM sensitivity. Funs like it for reception capability and sound.

General information:

  • Manufactured by Kenwood in Japan between 1987 to 1990
  • Digital 3 bands (MW-FM) PLL radio without RDS capability,
  • 20 random access memory presets, organized in 10+10
  • Coverage: LW 153kHz - 281kHz, MW 531kHz - 1.602MHz, FM 87.5MHz - 108.0MHz
  • Channel space: 1kHz for LW, 9kHz for MW, and 50kHz for FM
  • Intermediate frequency: 450kHz for AM and 10.7MHz for FM
  • Usable sensitivity: 10uV or 350uV/m on AM, 0.95uV on FM mono, and 25uV for FM stereo
  • Integrated circuits: FM IF amplifiers BA401 (2 pcs), FM IF IC: LA1235, AM IF IC: LA1245; stereo decoder: LA3401, PLL freq. synthesizer: LM7001, electronic tuning controller: uPD7538AC-045; FL display driver: LB1241, signal level LB1493, 3 terminal power regulators: AN7805F, uPC78L10J (2pcs), Operational amplifiers: M5223P (3 pcs), M5218P, NJM2901N, band selector LA7910, digital IC: uPD4013 D-flip-flop for switches, and uPD4069UBC inverter
  • Output frequency response on FM: 20Hz - 15kHz (+0.5...-0.5dB)
  • Signal/noise ratio: AM 52dB, FM 88dB mono, 76dB stereo
  • THD: on FM 0.1% for mono, 0.12% for stereo at 50...10kHz, on AM 0.3%
  • Stereo separation: 55dB at 1kHz, 40dB at 50...10kHz
  • Alternate channel selectivity: 60dB on Wide, 90dB on Narrow
  • Antenna input impedance for FM: unbalanced 75 ohms, for AM: loop antenna connector and an external antenna connection possibility
  • Output signal level/impedance : 0.18V on AM on 400hZ, and 0.6 V on FM at 1kHz, 3.3kohm
  • Power: 220V/50-60Hz, consumption: 13W
  • Dimensions: 440x78x317mm, 3.5kg

Good things:

  • Has a very clean sound with an extremely low noise level, low distortion,
  • Big FL display
  • Wide and narrow IF filters selection possibility for FM

Difficult, problematic items:

  • No mono/stereo switch - is automatically activated via manual/auto-scanning
  • No fuse on primer circuit of transformer - recommended being additionally inserted. Has just thermal protection
Is a 4 gang tuner on FM, and 2-2 for MW/LW. The schematic is very similar to KT5020 (differences: additional 3 terminal power rectifier for FM oscillator, different FM-IF circuit with LA1266 quadrature, and has one NJM4560 operational amplifier after LA3401 stereo decoder as output buffer).

Modification (based on FM TunerInfo, posted by JohnC, modified to my components):
Old electrolytics were ELNA type in average shape: some of them were OK (50% of 10uF/35V), but those with high capacitance and low voltage, like 100uF/10V or 220uF/6.3V were in poor condition. ALl were changed. Power line: C137 changed to 4700uF/25V; C138 and C150 to 680uF/50V; C142, C151, C152 to 1000uF/35V; C32, C51, C65, C108, C120, C132, C133, C135, C148, C165, C181, C194 to 100uF/63V; C54 to 390uF/35V; C193 to 3300uF/16V; C128 to 22uF/50V. At AC power input received an EMI filter circuit formed by 2.2nF/2kV ceramic capacitor, a 2x6.7mH filter coil, and after in parallel with the primer coil of transformer one 0.68uF/275Vac pp foil capacitor.
Audio output: all capacitors were changed with polypropylene type. Instead of 10uF I use 2 pcs of 4.7uF in parallel. Capacitors changed: C54, C60, C64, C78, C79, C82, C83.
All other electrolytics below 4.7uF changed to foil type.
Other recommended modifications: rectifier diodes to be changed into Schottky type, and insert an operational amplifier as audio buffer on output after LA3401 filters, like in KT5020 model.
Now has good stable image, wide soundstage, middrange is pretty good, nice tight bass and fairly deep, and the treble is clear.


Kenwood KT-1050L

Kenwood KT1050L

Is the smallest model from 1992-1993 (behind KT2050 and KT3050). Radio quality (and radio part schematic) is the same as the model KT2050, excepting the memory of previously listened to station and automatic synchronization.

General information:

  • Manufactured by Kenwood Portugal at 1992-1993
  • Digital 3 bands (LW-MW-FM) PLL radio,
  • 30 memory presets, which can be mixed between AM and FM
  • Coverage: LW 153 - 281kHz, MW 520kHz - 1.710MHz, FM 87.5MHz - 108.0MHz
  • Usable sensitivity: 22uV on LW, 13uV on MW (400uV/m), and 0.7uV on FM (mono) and 22uV for stereo - via a very sensitive JFET FM tuner
  • AM/FM Tuner System IC: LA1266, stereo decoder: AN7470, direct PLL frequency Synthesizer IC: LM7001, uController and FL tube driver: CXP5014, LED driver for signal strength: LB1433N, + M5223 and XRA10393 opamps.
  • Output frequency range: 30Hz - 15kHz (+0.5...-2dB)
  • Signal/noise ratio: LW 47dB, MW 50dB, FM 68dB mono, 63dB stereo
  • THD: on FM 0.15% for mono, and 0.4% for stereo, on AM 0.5%
  • Stereo separation: 48dB
  • Line output impedance: 3.3 kohm
  • Line output levels: 180 mV in AM mode, 0.6 V in FM mode
  • Antenna input impedance for FM: 75 ohm
  • Power: 230V/50Hz, Consumption: 10W
  • Dimensions: 440 x 79 x 264 mm, 2.6 kg

Good things:

  • Very good sensitivity on FM (0.7uV) and AM: 13uV on MW and 22uV on LW
  • Used components were good quality (at that time).

Difficult, problematic items:

  • Memory is organized like 3 x 10 = 30 positions, but from first position cannot be selected just 9 (the 0 button can be used just with 1, 2 or3). With this, I can say just 9 stations can be selected directly on the first page.
  • The display is situated too deep, cannot be seen just from a narrow-angle from the front side.
  • The transformer is always connected, and the radio is switched electronically with push-button or via remote controller -> extra consumption.
  • The mainboard is difficult to be taken out for repair/modification, because of short deepness (just 264mm): connectors are mounted on PCB and screwed to the rear panel, and the FL display on the front, mounted also on PCB are too deep in the front cover. To remove it is necessary to remove the back or the front of the tuner.
  • No narrow or wide FM IF selection possibility.
Generally: is a very good, sensible tuner for FM DX audio program listening with good selectivity.
As usual, was necessary to change all electrolytic capacitors. In RF parts received tantalum type capacitors, in other areas, below 4.7uF film capacitors, in audio part Nichicon Fine Gold, in the power line, above 22uF Nichicon or Rubycon capacitors.



Luxman


Lux Corporation was founded in Japan in June 1925, by T. Hayakawa and his brother K. Yoshikawa. The company began as the radio equipment department of Kinsuido Picture Frame Store in Osaka, until then only an importer of picture frames, and was founded just ahead of the first radio broadcast that year.
At the time, Japanese radio listeners were dependent on technology originating in the United States and Europe. Importing radio equipment and parts was a very forward-looking enterprise for Lux, and passersby often crowded the store to hear the inviting sounds of the radios on display. Lux Corporation later decided that to compete effectively as a supplier, it had to not only sell equipment but manufacture parts in-house to reduce the costs of importing, beginning the creation of the Luxman brand. As a result of this pursuit, Luxman became famous for the output of various quality transformers and switches in Japan, and today is one of the oldest manufacturers in Japan of electronic components, which is reflected in the company's tagline "Ultimate Fidelity since 1925". In the mid-1970s and early 1980s, Luxman rose to prominence in the world hi-fi community, owed to the quality sound produced by its equipment. Luxman was primarily a specialist in making vacuum tube amplifiers of the highest caliber. One of the traits of Luxman equipment from this era is the quality and warmth of vacuum tube sound, paired with powerful solid-state electronics and often beautiful, minimalist aesthetic designs.
An engineer by the name of Atsushi Miura married Mari Yoshikawa (Mr. K. Yoshikawa's eldest daughter) and became a part of the founding 'Luxman' family. Atsushi Miura's father was an audio engineer and was head of Luxman for many years in Japan. In the early 1980s, Atsushi took over the reins from his father to run Luxman. Sensing the Japanese audio industry was heading towards cheaper mass-produced components and against the founding philosophy of Luxman, Atsushi sold Luxman to Alpine in 1984, before starting the Airtight audio brand. Alpine, wishing to merge their home hi-fi divisions and Alpage brand with Luxman gear, took corporate actions which nearly bankrupted Luxman. The first of these corporate mistakes was getting Luxman involved in a hi-fi market share war with rival consumer electronics brand Yamaha. Up to the point of the merge, Luxman was revered as a prestigious audio brand; one that sold its equipment in specialist independent hi-fi shops. Post-merge, Luxman looked to sell their products to companies such as Costco (United States) and Richer Sounds (UK) to compete with Yamaha. This plan resulted in much confusion amongst consumers, as well as their perception of the brand's values. Where Luxman's reputation was in high-end and often expensive markets, its new distributors had reputations for selling in budget and low-value markets, causing problems for existing dealers and consumers loyal to Luxman's values. The second corporate mistake by Alpine was problems with product branding and poor product planning. While Alpine equipment was seen as "okay" and "acceptable" in most consumers' eyes, Luxman was seen as a perfectionist and even elitist brand. The co-branding of cheap and inferior plastic Alpine products with expensive Luxman gear (Luxman equipment was badged Alpine/Luxman) in both Alpine and Luxman factories caused further confusion amongst consumers. This move totally destroyed the image and, ultimately, the sales of Luxman equipment, and the company ended up retreating from all its sales network worldwide except Japan.
Alpine, due to all the troubles it experienced with the Luxman brand, sold it off in 1994. In 2009, Luxman Corporation was acquired by the International Audio Group Ltd. IAG.


Luxman T-4

Luxman T-4

This tuner, part of Studio Standard Series, was made in 1978 are equipped with Accutouch Closed Loop Lock(ACLL), which offers perfect accuracy and unconditional stability in FM tuning, which interacts with the Accutouch system to provide a mechanical lock on the tuning knob when the station is precisely tuned in. The front has a clean minimalist design: AM/FM band selector, Mode switch (Mono/Stereo), FM IF Bandwidth Selector (Wide/Narrow), FM Muting level adjuster, tuning know and power switch. On backside has an additional DIN FM antenna connector.

General information:

  • Manufactured between 1978-1979 by Lux Corporation in Japan
  • 2 band analog superheterodyne receiver, MW and FM
  • Coverage: MW 525kHz - 1.605MHz, FM 87.5MHz - 108.0MHz
  • Antenna input impedance for FM: 300 ohms balanced and 75 ohms unbalanced (terminal and also with DIN connector),
  • No preset memory for FM
  • Usable sensitivity: 0.9 uV on FM mono and 22 uV for stereo; 250uV/m on AM
  • Intermediate frequencies: 450kHz for AM, and 10.73MHz for FM
  • Used ICs: FM IF system LA1231; AM tuner: HA1197; MPX decoder uPC1173C; signal level LED driver BA656, operational amplifiers for CLL and audio output buffer NJM4558D
  • Signal to noise ratio: mono 75dB, for stereo no specified FM
  • Muting threshold: 5-300uV
  • Harmonic distortion: mono 0.08%, stereo 0.15% for FM at 1kHz
  • Output frequency range on FM: 30Hz - 15kHz (+1...-1dB)
  • Output voltage and impedance: 1 V on FM and 0.3V on AM / 100 ohms
  • Stereo separation: 48dB at 1kHz
  • Power: ~220V/50Hz, consumption 10W
  • Dimensions: 438 (W) x 84 (H) x 331 (D) mm, 6.5 kg.

Good things:

  • Beautiful minimalist front panel, warm and very clear sound
  • Closed Loop Lock, which makes it easy to tune exactly on station the tuner

Problematic things:

  • The signal-LEDs are deep in panel, can be seen just from certain angles
  • No tune indicator, just the signal strength
Interesting parts: some modules are separated with capacitor-multiplier circuits in the power line, like the FM oscillator and FM tuner, the audio output buffer, and the CCL circuit decreasing the noise of which comes from the power line to those units.
The oil-paper capacitors from the main switch were cracked, and the epoxy cover starts to peel off. Both were replaced with 2.2nF/3kV ceramic disk capacitors.
Power section: C103 and C168 now is 100uF/25V solid electrolite capacitor (was necessary to decrease the value of R202 from 47k to 15k), C175 now is 3300uF/25V, C176 is 2200uF/25V, C147, C169, C172, C173, C216, C311, C312, C313 now are 470uF/35V, C163 is 10uF/35V.
In signal path C158 and C159 now are 3.3uF/100V pp, C161 and C162 now are 0.47uF/63V pp, rest below 4.7uF all pp.




Marantz


Marantz is a company that develops and sells high-end audio products. The company was founded in New York, but is now based in Japan. The first Marantz audio product was designed and built by Saul Marantz in his home in Kew Gardens, New York. The company had a major influence in the development of high fidelity audio systems, and reached the high point of their success in the mid to late 1970s. During the 1980s, while owned by Philips, a pioneer in compact disc technology, Marantz sold some very well received CD players, but other products in the line were not as successful as in the past. Beginning in the early 1990s, Marantz focused on higher-end components. In 2001, Marantz Japan acquired the brand from Philips and owned all overseas sales subsidiaries. 2002 merged Marantz with competitor Denon into D&M Holdings Inc., later named in D+M Group. On March 1, 2017, Sound United LLC completed the acquisition of D+M Holdings.


Marantz ST 450

Marantz ST-450

Is a very fine tuner with the second best selectivity on MW I ever meet on tuners, 10uV (behind Kenwood Basic T2 tuner)! Also, the FM selectivity is good: 0.9uV. Inside is full analog, just the display is digital. Has a 4 stage FM tuning capacitor, a precision tuning system with digital readout and servo lock, pilot frequency rejection circuit, FM muting.

General information:

  • Manufactured by Marantz in Japan between at 1979-1982
  • Digital 2 bands (MW-FM) PLL radio (exist also a 3 band version, with LW named ST 450L),
  • No preset memory
  • Coverage: MW 531kHz - 1.602MHz, FM 87.5MHz - 108.0MHz
  • Usable sensitivity: 10uV(!) on MW and 0.9uV on FM mono and 20uV for FM stereo - via a very sensitive MOSFET FM tuner
  • FM IF IC: LA1231N, AM tuner IC: LA1240, stereo decoder: HA11223, uController and display driver: LC7258, prescaller: DS8629, signal level indicator LB1415
  • Output frequency range: 30Hz - 15kHz (+0dB...-1.0dB)
  • Signal/noise ratio: AM 55dB, FM 76dB mono, 70dB stereo
  • THD: on FM 0.17% for mono, and 0.2% for stereo
  • Stereo separation: 45dB
  • Channel balance: 0.2dB
  • Alternate Channel Selectivity (FM): 70dB
  • Line output impedance and level: 1.8 kohm/700mV
  • Antenna input impedance for FM: 75 ohms or 300 ohms
  • Power: 220-240V/50Hz, Consumption: 14W
  • Dimensions: 416x73x194mm, 3.2kg

Good things:

  • Has a very clean sound, low noise, good channel separation
  • Discrete output amplifier instead of an operational amplifier IC
  • Very good sensitivity on MW (10uV) with its own frame antenna, and 0.9uV on FM
  • High quality of electrical parts used, especially in case of solid capacitors, coils
  • Has a very fine tunning mechanism called Gyro Touch, smooth running, but easy and fast you can slide from one end to another one of scale

Difficult, problematic items:

  • No memory preset possibility
In the case of such old tuners was necessary to change all electrolytic capacitors (originally all were ELNA brand). In the audio part, I use audio grade capacitors also in the power line (Nichicon Fine Gold, etc). In the RF part power line I use tantalum capacitors and in the display part tantalum and OSCON. Used IF filters: for AM CFM2-455B, and for FM SFE10.7MS3G, SFE10.7MD1. Their central frequency is 10.73MHz. Crystal: 4.000MHz.



Marantz ST 530

Marantz ST-530

Is a very good FM tuner with dual gate MOSFET front end with twin varactor type tuning stage. FM sensitivity is 0.7uV. Inside has a digital synthesizer. Record programable: up to 6 stations can be recorded alternatively via the original Marantz Bus system, last station memory, and multiplex pilot canceler. At the backside has a switch to select the steps for AM and FM: 9/10kHz for AM, and 50/100kHz for FM (European and American radio standard).

General information:

  • Manufactured by Marantz in Japan between at 1983-1984
  • Digital 2 bands (MW-FM) PLL radio (exist also a 3 band version, with LW named ST 530L),
  • 8+8 preset memories, 8 for FM and 8 for AM
  • Coverage: MW 522kHz - 1.611MHz, FM 87.5MHz - 108.0MHz (LW 153 - 353 kHz)
  • Usable sensitivity: 6uV (in the user manual is written 350uV) on MW and 0.7uV on FM mono and 22uV for FM stereo
  • FM IF IC: HA11225; AM tuner IC: LA1245; stereo decoder: HA11223; uController and display driver including the signal level indicator: uPD1704C-544; prescaller: uPB553AC
  • Output frequency range: 30Hz - 15kHz (+0dB...-1.05B)
  • Signal/noise ratio: AM 54dB, FM 80dB mono, 72dB stereo
  • THD: on FM 0.1% for mono, and 0.2% for stereo
  • Stereo separation: 50dB
  • Channel balance: 0.2dB
  • Alternate Channel Selectivity (FM): 70dB
  • Line output impedance and level: 1.8 kohm/150mV
  • Antenna input impedance for FM: 75 ohms or 300 ohms
  • Power: 110-120/220-240V and 50/60Hz, Consumption: 12W
  • Dimensions: 416x55x300mm, 2.9kg

Good things:

  • Has a very clean sound, low noise, good channel separation
  • Discrete output amplifier instead of operational amplifier IC or direct output from the stereo decoder
  • Very good sensitivity on FM: 0.7uV
  • High quality of electrical parts used, especially in case of foil or ceramic capacitors, coils
  • Has very sensible switches, operates smoothly

Difficult, problematic items:

  • On MW is not as sensible as are mentioned in brochures (6uV on MW), I think is closer to 350uV which is written in the service manual. The sensitivity on MW is much lower compared with Marantz ST450, which on MW has a real 10uV with its frame antenna.
All electrolytic capacitors (originally all were ELNA brand). were changed. In the audio part, I use audio grade capacitors (Nichicon Fine Gold, etc), in power line Rubycons. In the RF part power line and for the microcontroller I use tantalum capacitors Used IF filters: for AM SFP-450H, and for FM SFE10.7MD-1, SFE10.7MS3G. Their central frequency is 10.70MHz. Crystal: 4.500MHz.


Marantz ST-64L

Marantz ST-64L

Is a state-of-the-art digitally synthesized tuner with preset convenience and connections for BUS remote control. Has quartz synthesized tuning for drift-free reception and autotune possibility. The high sensitivity front end with low noise and low distortion makes the best out of the high-quality broadcast. Has also a switchable IF bandwidth to pick out the stations under difficult reception conditions or to achieve the best possible stereo separation and lowest crowded bands. Despite its excellent parameters, its exterior looks horrible - I think is a worst design ever made by Marantz.

General information:

  • Manufactured by Marantz in Japan between at 1985-1987
  • Digital 3 bands (LM-MW-FM) PLL radio,
  • 24 memory presets:16 for FM and 8 for AM
  • Coverage: LW 153kHz - 281kHz; MW 531kHz - 1.602MHz, FM 87.5MHz - 108.0MHz
  • Usable sensitivity: 800uV on LW, 350uV on MW and 0.7uV on FM mono and 20uV for FM stereo - via a very sensitive MOSFET FM tuner
  • FM IF IC: LA1231 and uPC1136H, AM tuner IC: LA1245, stereo decoder: KB4437, uController: uPD1704C-552, prescaller: uPB553AC, display driver: uPD6320G; signal level indicator AN6876
  • Output frequency range: 20Hz - 15kHz (+0.5dB...-1.5dB)
  • Signal/noise ratio: AM 54dB, FM 85dB mono, 76dB stereo
  • THD: on FM 0.05% for mono, and 0.08% for stereo
  • Stereo separation: 55dB
  • Channel balance: 0.2dB
  • Alternate Channel Selectivity (FM): 75dB
  • Line output impedance: 10 kohm
  • Antenna input impedance for FM: 75 ohms or 300 ohms
  • Power: 220-240V/50Hz, Consumption: 12W
  • Dimensions: 416x73x295mm, 3.4kg

Good things:

  • Has a very clean sound, low noise, good channel separation
  • Discrete output amplifier instead of an operational amplifier IC
  • Very high sensitivity: 0.7uV on FM!
  • Program records allow the tuner to switch between 6 stations for unattended recording
  • Last station memory - tuner switches on with the last station listened (at that time was a new thing)
  • High quality of electrical parts used, especially in case of solid capacitors, coils

Difficult, problematic items:

  • Memory is organized like 3 x 8 = 24 positions (A:1-8, B:1-8, C:1-8). Should be more natural 3x10 = 30.
  • Has only 1 antenna input. Some tuners have 2, and for DXing could be more suitable...
  • Has a very poor design, and the display is mounted too deep
In the case of such old tuners, all electrolytic capacitors should be changed. In the audio part are recommended to use audio grade capacitors also in power line (Elna SilmicII or Nichicon MUSE etc). In RF part power line I use tantalum capacitors. This tuner uses 5 lamps, all 8V/50mA -> can be replaced easily with green LEDs, increasing just their serial resistor from 10 ohms to 270 ohms. The polarity can be determined via schematics and PCB drawing from the service manual. Used IF filters: for AM SFP450H, and for FM SFE10.7MS3G, SFE10.7MA8-A. Crystal: 4.500MHz


Marantz ST-6000

Marantz ST-6000

The Marantz ST 6000 is a reasonably well built 4 gang equivalent, 4 filters, dual bandwidth, AM/FM tuner manufactured in China. Has a dual-gate MOSFET front-end, quartz-locked digital tuning with low noise, drift-free reception of stereo FM, Wide/narrow switchable IF bandwidth, 60 preset memory, D-Bus connector for system remote control (via amplifier), and has a beautiful solid aluminum front panel with minimalist and modern design.

General information:

  • Manufactured by Marantz in China (!) between 1999-2004
  • Digital 3 bands (LM-MW-FM) PLL radio,
  • 60 memory presets:30 for FM and 30 for AM
  • Coverage: LW 146kHz - 290kHz (1 kHz step); MW 522kHz - 1.622MHz (9 kHz step), FM 87.5MHz - 108.0MHz (50 kHz step, or 10 kHz in Fine step mode within +-50kHz range)
  • Usable sensitivity: 50dBuV/m on MW, 57dBuV/m on LW and 1.2uV on FM mono
  • FM IF IC: LA1235, FM IF amplifier: TA7060AP, AM tuner IC: LA1135, stereo decoder: LÁ3401, uController and FL display driver: ANAM1288T/TMP87PM78F, RDS decoder: TDA7330BD, PLL LC72131M, output buffer: MC4558S, stabilizer KA7815ZA and KA7805ZA
  • Output frequency range: 20Hz - 15kHz (+1.0dB...-3.0dB)
  • Signal/noise ratio (1 kHz): LW 45dB, MW 50dB, FM 80dB mono, 75dB stereo
  • Selectivity (+-400 kHz): in Wide mode 65 dB, in Narrow mode 80 dB
  • THD: on FM 0.08% for mono, and 0.15% for stereo, on AM 1.0%
  • Stereo separation (1 kHz): 50dB
  • Channel balance: 0.5dB
  • Line output impedance: 2 kohms
  • Antenna input impedance for FM 75 ohms unbalanced, 2 selectable inputs: A & B, indoor loop antenna for AM
  • Power: 230V/50Hz, Consumption: 7.6 W
  • Dimensions and weight (net): 440 x 96 x 307 mm (WxHxD), 3.8kg
  • Selling prices were around 279$ in 2001

Good things:

  • Has a very clean and warm sound, low noise, good channel separation
  • Use operational output amplifier after stereo decoder
  • Timer function: used for presetting the time when the system is turned on and off every day at a specified time (needs a Marantz amplifier which can communicate with this tuner)
  • Signal level indicator
  • 2 selectable antenna inputs for FM
  • Automatic scan and storage operation
  • RDS capability: PTY, PS, RT, CT, TA
  • "anti-birdie filter" installed after MPX decoder, no any pilot tone or subcarrier suppressor mentioned, but the output is quite clean

Difficult, problematic items:

  • Low quality of electrolytic capacitors used (Daewoo)
  • Medium selectivity, nothing special
  • The FL display has low intensity, in a bright environment is difficult to be read
  • The two voltage regulator IC after one hour of operation is very hot, and that temperature change is not good for ceramic filters
  • The built-in clock loses time if the tuner is unplugged or the power goes out (but the stored stations are kept). When the power comes back, and we start to listen to a station with RDS, automatically will be adjusted
When I purchased this tuner and the first time I listen to it, I was completely disappointed. Regarding excessive marketing, in any magazine in its time was mentioned the ST-6000 as one of the best tuners. In reality: average sensibility. The 2 filters Wide and 4 filters Narrow IF employs a single TA7060 IF operational amplifier feeding a LA1235 FM IC. No extra feature compared to other top tuners from that era (ex. Denon TU-1500RD), and additionally was made with the worst electrolytic capacitors inside what I ever see from a market leader company (they use in my set Daewoo RM), and just after 19 years from manufacturing some of them were completely dried - ex. a 220uF/25V Daewoo RM capacitor measured: 88uF, 1.5 ohms ESR and 21% loss!
In several forums are mentioned just as a good sounding tuner, and are recommended several modifications: not just increasing in some positions the values of the capacitors or replacing them with a higher grade, changing rectifier diodes to Schottky type, but also changing the operational amplifier type from the output (the audio buffer is a Fairchild KA4558s SIP-9 IC), modification of audio feedback network, and in my opinion, also the voltage regulator ICs are better to be mounted on the back of chassis to transfer the dissipated heat outside from the body, or to changed into a less noisy LM317 plus some additional components. Although there is no bottom plate in the steel chassis, board removal is very easy regarding connectors used on it.
In general is a good tuner, especially when the signal is enough strong - the sound is full with warm bass. It has a slight loudness-like response, tending to accent the bass a little in comparison with the treble, but this could just as well be very linear low range and slightly depressed high range, caused by the need to filter out the pilot tone. Nevertheless, this is an extremely listenable sound, with a bit more warmth than is needed.
I did not recommend it for DX or for the countryside, where some stations have a low signal level, but if you live in a well covered area, this tuner has a magnific sound!



NAD


The NAD Electronics (NAD Electronics) company was founded in London, England, in 1972 by Dr. Martin L. Borish, an electrical engineer with a PhD in physics. Its most famous product is the late-1970s NAD 3020, an integrated amplifier designed by Bjřrn Erik Edvardsen, which was highly regarded by various magazines in Britain. NAD's philosophy is to include only genuinely useful features for aesthetically understated designs when compared to other competitors' products. NAD was one of the first audio manufacturers to outsource the manufacturing of its products to electronics factories in east Asia. NAD was acquired by the Danish firm AudioNord in 1991 and subsequently sold in 1999 to the Lenbrook Group of Pickering, Ontario, Canada.



NAD 4220

NAD 4220

As part of the new series from 1987, is one of the best tuner of NAD. Has ultra-linear IF filters, a switchable blend circuit, a high SN ratio (>75dB), and 10 random preset memories.

General information:

  • Manufactured in Taiwan, NAD Electronics, Inc Boston/London in 1987
  • Digital PLL analog 2 bands (MW-FM) superheterodyne radio,
  • 10 random memory preset, 5 for FM and 5 for AM
  • Coverage: MW 522kHz - 1.611MHz, FM 87.5MHz - 108.0MHz
  • Usable sensitivity: 5uV(!) on MW and 2.0uV on FM mono and 37uV for FM stereo
  • AM/FM IF IC: LA1265, stereo MPX decoder: LA3401, uController: TC9147P, LED display driver: TD6301AP, prescaller: TD6104P, tuning level indicator LB1450, power supply regulator: L78M12
  • Output frequency range: 30Hz - 15kHz (+0.5dB...-0.5.0dB)
  • Signal/noise ratio: FM mono 80dB, FM stereo 75dBdB, on AM 45dB
  • THD: on FM 0.09% for mono, and 0.09% for stereo at 1kHz, 0.3% on AM
  • Stereo separation: 50dB at 1kHz
  • IF rejection: on FM 100dB, on AM 35dB
  • RF intermodulation: 65dB
  • Subcarrier suppression (19 & 38kHz): 60bB
  • Channel balance: 0.2dB
  • Alternate Channel Selectivity (FM): 65dB
  • Line output impedance and level: 600 ohm/700mV
  • Antenna input impedance for FM: 75 ohms or 300 ohms
  • Power: 220V/50Hz, Consumption: 10W
  • Dimensions: 420x76.2x250mm, 3.2kg

Good things:

  • Has a very clean sound, low noise, good channel separation
  • Very simple front panel with LED display
  • No any lights when is switched off
  • Clever ground trace on the PCB
  • I have the European version, but the transformer has 2x110V coils on the primer side

Difficult, problematic items:

  • The power regulators (Q501L78M12, the Q502/2SA796Y), and the R502/56ohms and 1W) generate a lot of heat, heating the power filtering capacitors
  • The heatsink screwed on Q501 and Q502 are made from iron, not copper or alumina
  • The PCB is a low grade, can be changed components very carefully to avoid piling of the pattern
  • The main RF and audio ICs has no buffer capacitor on their power supply, just 22nF ceramic type
Is a predecessor of more common NAD 4225, which has 2x7 preset memory, but completely same schematic (excepting this additional memory selection). Modifications:
Power: both heat generators (Q501 and Q502) were mounted on the internal stiffener plate. Is still iron, and internal, but the heat was taken out from the neat of the capacitors
The power line input received an EMI filter, and related filtering capacitors were changed and/or increased their values. C510 390uF/35V, C515 and C519 330uF/50V, C516 and C522 100uF/63V, C518 and C520 47uF/35V solid electrolyte. C143 received in parallel a 100uF/16V and C117 replace with 100uF/16V, both solid electrolyte capacitors. C904 received in parallel an additional ceramic capacitor, 4.7uF/35V.
This tuner has a musicality, very listenable - but different from Marantz or Technics. Like a tuner with a clear character, a different identity.



Nordmende


Nordmende cames from Norddeutsche Mende-Rundfunk GmbH, a radio company founded in 1923 by Otto Hermann Mende in Dresden, and was rebuilt after WWII in Bremen in 1947. In the 1980s, the factories in Bremen were closed, Nordmende becoming purely a Thomson trademark (sold by family). This means this radio was made in the transition era, but Nordmende already was a Thomson affiliate.



Nordmende TU-1300

Nordmende TU-1300

Is a very fine tuner with the best selectivity on FM, 0.9uV, outperforming other tuners with the same official sensibility! Is a full analog tuner, with a digital display, but on FM tunning are made via varicap diodes. The tuner complete name: Hifi Tuner Philharmonic TU-1300 981.143H

General information:

  • Manufactured by Nordmende, Norddeutsche Mende-Rundfunk GmbH (Sterling), Bremen-Hemelingen at 1981
  • Analog 3 bands (MW-LW-FM) superheterodyne radio,
  • 6 memory preset for FM
  • Coverage: MW 520kHz - 1.620MHz, LW 15kHz - 350kHz, FM 87.5MHz - 108.0MHz
  • Usable sensitivity: 10uV(!) on MW and 0.9uV on FM mono and 23uV for FM stereo - via a very sensitive MOSFET FM tuner
  • FM IF IC: HA11225, AM tuner IC: LA1245, stereo decoder: uPC1161C, adjusting voltage stabilizer: HA17723G, uController and display driver: LC7258, prescaller: MSL2312RS, signal level indicator LB1405
  • Output frequency range: 20Hz - 15kHz (+0dB...-1.0dB)
  • Signal/noise ratio: FM 68dB
  • THD: on FM 0.1% for mono, and 0.2% for stereo
  • Stereo separation: 47dB
  • Channel balance: 0.2dB
  • Alternate Channel Selectivity (FM): 50dB
  • Line output impedance and level: 1.8 kohm/700mV
  • Antenna input impedance for FM: 75 ohms or 300 ohms
  • Power: 220V/50Hz, Consumption: 13W
  • Dimensions: 440x108x289mm, 4.2kg

Good things:

  • Has a very clean sound, low noise, good channel separation
  • Very good sensitivity on MW (10uV) with its ferrite antenna, and 0.9uV on FM

Difficult, problematic items:

  • Memory preset possibility just for FM
  • The audio band starts from 20Hz, has less bass than Technics SA5370 or Marantz ST450
In the case of such old tuners was necessary to change all electrolytic capacitors (originally all were ELNA brand). In the audio part, I use audio grade capacitors also in the power line (Nichicon Fine Gold, etc). In the RF part power line I use tantalum capacitors and in the display part tantalum.



Onkyo


Onkyo Corporation is a Japanese consumer electronics manufacturer, specializing in premium home cinema, and audio equipment, including AV receivers, surround sound speakers and portable devices. The company started under the name of Osaka Denki Onkyo K.K in 1946. The word Onkyo translates as "sound resonance". The current Onkyo Corporation umbrella includes the Integra and Integra Research divisions as well as the main Onkyo brand. In March 2015, Onkyo purchased Pioneer Corporation's Home Electronics Corporation. In return, Pioneer took a 14.95% stake in Onkyo.


Onkyo TX-2500

Onkyo TX-2500

This is a nice Onkyo receiver from 1976, a younger brother of TX-4500. Has a very conservative front, frontend with FET, PLL MPX decoder, tuning servo-locking, Loudness, High-filter (from 6kHz -12dB/octave), tape 1 & 2 monitor, and "accutouch" tuning knob (temporarily inhibits the locking circuits for manual, large-scale tuning: hands-on; when released, hands-off, the locking function clicks back in and fine-tunes on its own the locked station until the tuned indicator lights up). Has the possibility to connect Dolby FM adaptor for Dolby FM broadcasts. Its successor was the TX-2500 MKII with a bit better specification for preamp and tuner section, and quite a bit more power, too.

General information:

  • Manufactured between 1976-1978 by Onkyo Co., in Japan. On the net I found sources, where is mentioned this receiver was manufactured from 1975, on other sites 1977.
  • 2 band analog superheterodyne receiver, MW and FM
  • Coverage: MW 530kHz - 1.605MHz, FM 87.5MHz - 108.0MHz
  • Antenna input impedance for FM: 300 ohms balanced,
  • Antena for AM: build in ferrite core and external terminal
  • No preset memory for FM
  • Usable sensitivity: 1.6 uV on FM mono and 4 uV (!) for stereo; 25uV on AM
  • Intermediate frequencies: 455kHz for AM, and 10.7MHz for FM
  • Used ICs: FM IF system: HA1137; AM radio receiver: HA1151; MPX decoder LA3350; operational amplifiers TA7136, TA7504
  • Signal to noise ratio: FM mono 65dB, FM stereo 60dB, AM 40dB
  • Output frequency range on FM: 30Hz - 15kHz (+0.5...-2dB)
  • Stereo separation (1kHz/10kHz): 37/30 dB
  • THD: 0.2% for FM mono, 0.4% FM stereo, 0.8% for AM
  • Power output: 27W/8 ohms, 2-60kHz within +-1dB, with 0.5% THM; 34W/4 ohms
  • Damping factor: 40 at 8 ohms, 1 kHz, 10W
  • Phono sensitivity/impedance: 2.5mV/50kohms
  • Phono Overload: 150mV RMS 1kHz 0.5% THD
  • RIAA curve deviation: +-0.2dB, 30...15kHz
  • Tape Play/Rec and Dolby Out: 150mV/50kohms
  • Dolby In: 580mV/50kohms
  • Bass control: +-10dB at 100 Hz
  • Treble control: +-10dB at 10 kHz
  • High Filter: 6kHz
  • Loudness: +5dB at 100 Hz and 10 kHz
  • Signal to noise ratio: Phono 65dB, Tape 80dB
  • Power: 110V/120/220/240V 50/60Hz, consumption max. 320W
  • Dimensions: 488x163x400 mm, 12 kg.

Good things:

  • Has a very clean sound, with an exceptional stereo feeling
  • Has a separate transistor buffer at output instead of direct signal from MPX IC or via operational amplifier
  • Very good sensitivity and selectivity on FM
  • Has analog signal strength and center tuning meters
  • Accutoutch sensibility can be adjusted with a 3 position switch found on rear panel of radio

Difficult, problematic items:

  • Has a FET input FM tuner (MKII version has a mosfet one), but the sensitivity is quite good
  • Some components are missing, like R154 100k semi-adjustable potmeter was replaced with 22 kohm resistor, but the whole radio works very well
With more than 44 years, is a receiver with a very pleasant sound. Was necessary to change all electrolytic capacitors, all bulbs. The scale pointer, Stereo, Tuned, and Locked indicators were changed with LEDs, just for the pointer LED was necessary to insert additionally one diode and 22uF/16V capacitor, because this was the only bulb powered from AC. Also was built in an EMI filter after AC input.
The radio part has 2 versions: NAIMX-345, a simpler, and NAIMS-345, a more complex one (S means Super?), this last one is a better version, seems more similar with MKII (looks like a transition between them). I have the version NAIMX-345, but on the PCB can be seen position of components from NAIMS-345, but not all of them. Ex. position of T102 was shunted, and I replaced with the right C-L components, or in L101 position was mounted a 100ohms resistor (like in MKII), I replaced it with 3.3uH inductor.
Its sensibility outperforms some tuners with better specifications.
The TX-2500 on AM are with 2 gangs, on FM are with a 3-gangs variable capacitor, two IF amp stages, 2 pcs of 10.7MHz ceramic filters, and an Onkyo-made low-pass filter (NMC-8-7). Recommended to be improved: the audio stage separation from common radio power with a 56 ohms resistor followed by a puffer capacitor 470uF/25V. In the RIAA feedback network, is recommended to be changed the C304/C404 from 3.9nF to 3.6nF+220pF - but to be identical, PP capacitors from same type and same manufacturer. I added 1-1 uF/100V in parallel with C905/C906 4700uF/80V Nichicon capacitors in main power supply.


Onkyo T-4210R

Is a rare unit with RDS. Has a blue, bright and saturated, and even something 2 color fluorescent display with an APR (Automatic Precision Reception) unit, choosing between mono/stereo, DX and Local in the function of signal strengths. Has Scan function, which scans and memorizes the strongest 20 stations at the touch of the Scan button. ARe eqiped with signal strengths meter, selectable display character input, battery-free memory (0.1F supercapacitor are used), AM loop antenna, and is RI remote system compatible.

General information:

  • Manufactured by Onkyo in Japan between 1991 - 1996
  • Digital 2 bands (MW-FM) PLL radio with RDS+EON capability,
  • 30 memory presets, organized in 3x10 groups
  • Coverage: MW 531kHz - 1.602MHz with 9kHz steps, FM 87.5MHz - 108.0MHz with 50kHz steps
  • Usable sensitivity: 25uV on AM, 1.0uV on FM (mono) and 20uV for stereo - via a very sensitive MOSFET FM tuner
  • FM/AM tuner IC: FM/AM tuner: LA1266, stereo decoder: LA7470, PLL freq. synthetizer: LC7001, uController and dot matrix VFD display driver uPD78044A, RDS decoder: uPC1346CS
  • Output frequency range: 30Hz - 15kHz (+-1.5dB)
  • Signal/noise ratio: AM 40dB; FM 73dB mono, 66dB stereo
  • THD: on FM 0.1% for mono, 0.2% for stereo; on AM 0.8%
  • Stereo separation: 40dB
  • Image rejection: on FM 80dB, on AM 40dB
  • IF rejection ratio: FM 90dB, AM 40dB
  • Line output impedance: 100 ohm
  • Antenna input impedance for FM: 75 ohm
  • Power: 230V/50Hz, consumption: 9W
  • Dimensions: 455x90x309mm, 3.7kg

Good things:

  • Has a very clean sound, low noise, average channel separation, good readable big display.
  • Automatic RF-attenuation for strong stations thanks to APR.
  • Has Radio Text - RDS EOS with PTY and TP. In 1991 this feature was rare
Difficult, problematic items:
  • Has a sound with leak bass.
I did not found on the net the schematic of T-4210R, but the radio part is the same as T-4210 (from 1986), and the RDS part with T-4310R (1993?) - combining them, you can have a detailed picture.
Modifications
All modifications covers the power lines, and noise reduction and sound improvements. On Power line: C002 100uF/16V replaced with 390uF/35V, C114 22uF/16 replaced with 100uF/63V, C205 470uF/16V replaced with 1000uF/35V, C220 47uF/16V replaced with 100uF/63V, C706 220uF/6.3V replaced with 390uF/35V, power cap of RDS 10uF/16V replaced with 100uF/63V, C902 2200uF/25V with 3300uF/25V, C904 470uF/16V replaced with 1000uF/35V, C905 10uF/50V with 100uF/63V, C907 47uF/16V with 100uF/63V, C913 47uF with 100uF/63V, C914 220uF/35V with 390uF/35V, C915 220uF/35V with 390uF/35V, C919&C920 with 390uF/35V. Received an AC power line filter: 2.2nF62kV, 2x7.8mH anf 0.68uF/275Vac.
Other changes: C117 1uF/50V to 3.3uF/100V PP, C169 10uF/35V to 4.7uF/63V PP, jumper J109 replaced with 3.3uH coil, C202 22uF/16V with 4.7uF/63 PP (based on input impedance was not justified to increase above 4.7uF), C211&C212 22uF/16V with 10uF/63V PP (that can be increased, depends by input impedance of preamplifier. The best solution should be a separate buffer on the end of MPX decoder).



Panasonic


Panasonic Corporation, (Panasonikku kabushiki gaisha) formerly Matsushita Electric Industrial Co., Ltd. is a major Japanese multinational electronics company, headquartered in Kadoma, Osaka. It was founded by Konosuke Matsushita in 1918 as a lightbulb socket manufacturer. In 1927, Matsushita adopted the brand name "National" for a new lamp product. In 1955, the company began branding audio speakers and lamps for markets outside Japan as "PanaSonic", which was the first time it used the "Panasonic" brand name. The company began to use the brand name "Technics" in 1965 for high fidelity audio equipment. Throughout the 1970s and early 1980s, Matsushita continued to produce high-quality specialized electronics for niche markets, such as shortwave radios, and developed its successful line of stereo receivers, CD players, and other components. The use of multiple brands lasted for some decades. While 'National' had been the premier brand on most Matsushita products, including audio and video, 'National' and 'Panasonic' were combined in 1988 as National Panasonic after the worldwide success of the Panasonic name.
Matsushita's brother-in-law, Toshio Iue, founded Sanyo as a subcontractor for components after World War II. Sanyo grew to become a competitor to Matsushita but was later acquired by Panasonic in December 2009.
Since that time, Panasonic closes its plasma (2011) and LCD (2021) displays manufacturing, solar panels (2021), and semiconductors (2019) manufacturing business.


Panasonic RF-B45

Panasonic RF-B45

Is a travel shortwave radio with SSB capabilities built at 1991, is the "little brother" of the RF-B65, very similar to Sony's legendary ICF-7600D

General information:

  • Digital shortwave portable (dual conversion):1st IF: 55.845 MHz; 2nd IF: 459 kHz; for FM: 10.7 MHz
  • Coverage: AM 144kHz - 29.995MHz (selected bands LM, MW, and 13 SW), FM 87.5MHz - 108MHz, continuous on the whole SW band (1622-29995 kHz in 5 kHz steps),
    • Shortwave bands - can be selected also by meters/wave length:
    • SW1: 2300 - 2495 kHz, 120 m
    • SW2: 3200 - 3400 kHz, 90 m
    • SW3: 3900 - 4000 kHz, 75 m
    • SW4: 4750 - 5060 kHz, 60 m
    • SW5: 5950 - 6200 kHz, 49 m
    • SW6: 7100 - 7300 kHz, 41 m
    • SW7: 9500 - 9775 kHz, 31 m
    • SW8: 11650 - 12050 kHz, 25 m
    • SW9: 13600 - 13800 kHz, 21 m
    • SW10: 15100 - 15600 kHz, 19 m
    • SW11: 17550 - 17900 kHz, 16 m
    • SW12: 21450 - 21850 kHz, 13 m
    • SW13: 25670 - 26100 kHz, 11 m
  • 9/10 kHz steps on LW/MW, 5 kHz steps on SW, and 50 kHz steps on FM
  • Synchronous detection
  • Sensitivity: FM 4uV/50mW output; LW 600uV/m 50mW output; MW 180uV/m 50mW output; SW 10uV/m at 50mW output
  • Possibility of SSB reception, but cannot be selected the LSB and USB
  • Fine tuning for AM SSB (is not followed by frequency meter) approx +-5kHz
  • Has just 18 presets: 9 for FM, and 9 for AM/SW. The 0 button make a scoll of preset stations
  • External antenna jack for LW, MW and SW
  • Alarm and sleep functions
  • Frequency synthesizer / microcontroller: µPD1724GB561
  • Output: 600 mW RMS Max., on an 7 cm (in some catalog mentioned 8 cm) 8 ohm speaker
  • Power: 6V - 4 AA size batteries or DC IN jack (- in interior!)
  • Dimensions/weight: 204 x 119 x 37 mm, 620 g (without batteries)
  • Produced: between 1991 - 1993

Good things:

  • Entering and recalling frequencies is pretty simple
  • Good selectivity, especially on FM (better than all Sony ICF-SW7600XX models).
  • Signal level indicator - 3 levels
  • Its sound is very clear, on FM is better than Sony's

Problems:

  • Not enough memory to store stations (just 9 for FM and 9 for whole AM)
  • The power-on button is on the lower right side - incommode to operate
  • The volume potentiometer adjusting is reversed: you should rotate it from top to bottom to increase the volume
  • The Power button has a green backlight LED, which is switched on continuously during operation. In nighttime listening, this green light is too bright and useless.
  • The radio is just mono, including the headphone jack. With stereo headphones, the radio can listen just on the left side.
  • The sound has lack of bass, probably regarding the output capacitor of the power amplifier
  • The Auto-Tunning runs just forward, but in a short time very precisely set the center frequency of stations
In general is a good travel radio, not as performant as Sony's ICF-SW7600 family, but its sensibility on FM can compensate for that. On the net scrolling on reviews, sometimes are mentioned as same, or rarely better than the Sony ICF-SW7600xx series.
Recommendation: I changed the CFX3 and CFX2 10.7Mhz (Murata type with 280kHz BW and 6-7dB loss) ceramic filters with a Murata 150kHz BW, 4-5 dB loss filters. Sensitivity lightly increased on FM, and no adjacent programs can be heard, and easily can be found the real transmission frequency of FM radio station.
The sound is very clear, especially on midrange and treble, but with less bass. This can be improved by changing the output capacitor from 220uF/6.3V to 470uF/6.3 solid electrolyte type.
Next step for improvement: to change the headphone jack into a stereo one, and to move the power button LED to backlight the LCD (more useful).



Philips


The Philips Company was founded in 1891, by Gerard Philips and his father Frederik Philips. Frederik, a banker based in Zaltbommel, financed the purchase and setup of an empty factory building in Eindhoven, where the company started the production of carbon-filament lamps and other electro-technical products in 1892. In the 1920s, the company started to manufacture other products, such as vacuum tubes. In 1927, Philips began producing radios.
In 1980, Dutch Philips Group bought the Marantz (in 2001 Marantz Japan acquired the brand back from Philips), and in 1984 bought out nearly a one-third share and took over the management of German company Grundig.
On 29 January 2013, it was announced that Philips had agreed to sell its audio and video operations to the Japan-based Funai Electric.


Philips L1W35T

Philips L1W35T

General information:

  • Manufactured at 1964 by Philips in Eindhoven
  • Just one band MW (AM) superheterodyne pocket radio with build in earphone, near battery case (via one switch can be selected)
  • Coverage: 525kHz -1622kHz (185m - 571m wavelength)
  • Intermediate frequency: 452kHz, 5 RF circuits
  • Power: 6V (4 pcs of AA batteries)
  • Power consumption without signal: 12mA
  • Output power: 120mW
  • Dimensions: 142x92x35mm, 300 gr.
This is my oldest radio with transistors (6 transistors: 3 pcs of AF127 for mixer-oscillator and IF (2), 3 pcs of AC132 for the preamp and power amp (2), and one OA70 diode for detector - all Germanium type). Sensibility is average, the volume potentiometer is scratching, but the whole radio is still working quite well.


Philips FT980

Philips FT980

This tuner was the top tuner of Philips, but this Philips FT980 basically is a Grundig development from Fürth (when Grundig and Marantz were already part of Philips) and was only plugged into a different housing by Philips for its brand and got a different device number. Technically almost or largely identical RF part (except for external design/housing and used microcontroller) are Grundig T-5200, T-5500, T8200 MKII, T-304, T4, Fine Arts T-904 or Marantz ST72L. Several webpages highlight its pleasant sound, very good reception quality, and also recommend it for DX.

General information:

  • Manufactured by Philips Portugal at 1990-1992
  • Digital 3 bands (LW-MW-FM) PLL radio,
  • 30 memory presets, which can be mixed between AM and FM
  • Coverage: LW 150 - 283kHz, MW 528kHz - 1.605MHz, FM 87.5MHz - 108.0MHz
  • 9/1 kHz steps on AM, 50/25kHz on FM - (auto/manual search)
  • Usable sensitivity: 200uV/m on LW, 200uV/m on MW (400uV/m), and 0.85uV on FM (mono) and 23uV for stereo - via a very sensitive MOSFET FM tuner
  • AM/FM Tuner System IC: LA1266, stereo decoder: LA3401, direct PLL frequency Synthesizer IC: LC7217, uController MC68HC11, FL tube driver: uPD7537A, RDS decoder LA2231, reset IC: M51957A, TA7061AP IF amplifier and RC4560 RDS filter opa.
  • Output frequency range: 10Hz - 15kHz (+0.5...+1.5dB)
  • Signal/noise ratio: LW 55dB, MW 55dB, FM 86dB mono, 78dB stereo
  • THD: on FM 0.08% for mono, and 0.12% for stereo, on AM 0.5%
  • Stereo separation: 50dB
  • Line output impedance: 3.3 kohm
  • Line output levels: 400 mV in AM mode, 370 mV in FM mode
  • Antenna input impedance for FM: 2 x 75 ohms (one for local, one for DX)
  • Power: 230V/50Hz, Consumption: 10W
  • Dimensions: 420 x 86 x 334 mm, 2.6 kg

Good things:

  • Very good sensitivity on FM (0.85uV),
  • Narrow and wide IF band selection possibility, with 5 ceramic filters! - 3 for wide, and +2 for narrow IF band,
  • 2 selectable FM antenna inputs: one for local, and one for DX,
  • Sensible RDS,
  • Used components were good quality (at that time).

Difficult, problematic items:

  • The RDS display just the radio station name, no Radio Text
  • The transformer is always connected to power line, and with the 2 regulator ICs heatsink generate a lot of heat,
  • Behind FL display were also components (electrolytic capacitors, resonator, resistors, etc) -> all capacitors were removed and mounted on the backside of PCB for easy access in future,
  • Has some timer possibility, but without the user manual, is difficult to use it
  • FM IF is 10.73MHz (ceramic filters with an orange dot), which means is difficult to upgrade them.

Generally: is a very good tuner with high sensibility and selectivity for FM DX audio program listening.
As usual for its age, was necessary to change all electrolytic capacitors. In RF parts received tantalum type capacitors, in other areas, below 4.7uF film capacitors, in audio part Nichicon Fine Gold, in the power line, above 22uF Nichicon or Rubycon capacitors.
On some portals are recommended to be changed the C311 adjustable capacitor with a teflon type, but in my one, I did not see any reason to change it. After comparing the schematics and specifications of the above-mentioned tuners, I decided to upgrade the tuner with component values used in Grundig Fine Arts T4 and/or Marantz ST72, changing R105 4.7k into 3.6k, R145 10 ohm into 4.7 ohms, R187 10k into 6.8k, R315 120k into 56k, and insert a 3.3uH (L11) coil in the power line of FM-IF operational amplifier. To my surprise, those were originally changed/inserted by manufacturer -> means the Philips FT980 RF parts differ from its service manual and are same with the RF parts used in Grundig Fine Arts T4. Marantz ST72 has additionally other values in the case of some components, like in FM oscillator or in FM tuner output amplifier, but I considered risky their changes regarding surrounded RF circuits.
List of other differences between Philips FT980 and Marantz ST72L: R16 8.2k/100, R165 1.2k/1k, R181 47/220, R301 31/390, R309 330/68k, R311 220k/68k, R322 3.9k/5.6k, C112 10n/47n, C113 10u/no, C145 4.7n/390p, L11 no/3.3u. The RF coils cannot be compared, because in both manuals has a different notation (looks like Philips and Marantz used a different notation system), but their position-number, appearance, and the capacitors from the circuit are the same.



Pioneer


Pioneer Corporation (Paionia Kabushiki-gaisha) commonly referred to as Pioneer, is a Japanese multinational corporation based in Tokyo, Japan, that specializes in digital entertainment products. In 1937: Pioneer's founder, Nozomu Matsumoto develops the A-8 dynamic speaker, and one year later, in 1938 Fukuin Shokai Denki Seisakusho (precursor of Pioneer) is founded in Tokyo as a radio and speaker repair shop. In May 1947 Fukuin Denki is incorporated, and in June 1961 Company name changed to Pioneer Electronic Corporation. Pioneer played a role in the development of interactive cable TV, the Laser Disc player, the first automotive Compact Disc player, the first detachable face car stereo, Supertuner technology, DVD and DVD recording, the first AV receiver with Dolby Digital, plasma display and Organic LED display (OLED). In March 2010, Pioneer stopped producing televisions as announced on 12 February 2009.[2] On June 25, 2009, Sharp Corporation agreed to form a joint venture on their optical business to be called Pioneer Digital Design and Manufacturing Corporation.[3] In September 2014, Pioneer agreed to sell Pioneer Home Electronics (Home A/V) to Onkyo. In June 2021, Voxx International announced that it had finalized a licensing agreement with the Pioneer and Pioneer Elite brands "for all markets, except China" as part of their acquisition of Onkyo.


Pioneer F90

Pioneer F90

The Pioneer F-90 (for Japanese market is F120, are absolutely same, exception the FM range) is a high-performance AM/FM tuner made by Pioneer (after F99X). Features a 4 gang FM tuner with DMOS first stage, a balanced mixer, three narrow-IF filters, a pulse-count detector called Digital Direct Decoder, and a novel switched-sinewave stereo decoder. The stereo demodulation capability is superior to the switching MPX circuits used by other companies, and high channel separation has been obtained. It has good sensitivity, excellent overload resistance, excellent immunity to spurious composite signals, very high AM suppression, very high ultimate S/N, extremely high modulation acceptance, and extremely low distortion. Has a Record level check for easy recording level adjustment.

General information:

  • Manufactured by Pioneer in Japan between 1982-85
  • Digital 2 bands (MW-FM) PLL radio,
  • 8+8 memory presets, 8 for AM and 8 for FM
  • Coverage: MW 522kHz - 1.611MHz, FM 87.5MHz - 108.0MHz
  • 9 kHz steps on AM, 50 kHz on FM - (auto/manual search)
  • Usable sensitivity: 150uV/m on MW, and 0.95uV on FM (mono) and 22uV for stereo
  • FM IF amp IC: 2 pcs uPC1163H, FM IF amp and detector: PA3007A, pulse count circuit: PA5006, stereo decoder: PA5007, AM dem and IF: LA1247, direct PLL Frequency Synthesizer and control IC: TC9147P, led display driver: TD6301AP, FM prescaller: TD6104P and M5218P opa.
  • Output frequency range: 20Hz - 15kHz (+0.2...-0.8dB)
  • Signal/noise ratio: MW 55dB, FM 93dB mono, 86dB stereo
  • THD: on FM 0.02% for mono, and 0.04% for stereo
  • Output frequency response on FM: 20Hz - 15kHz (-0.5...+0.5dB)
  • Stereo separation: 60dB at 1 kHz
  • Line output impedance: 900 ohm
  • Line output levels: 150 mV in AM mode, 600 mV in FM mode
  • Antenna input impedance for FM: 75 ohms unbalanced, and 300 ohms balanced
  • Power: 220V/50Hz, Consumption: 14W
  • Dimensions: 420 x 61 x 317 mm (WxHxD), 4.5 kg
  • Selling price at 1983: 650DM

Good things:

  • Very simple, clear front panel
  • Extremly high S/N ration of FM: 93dB in mono, and very low distortion: 0,0095% in mono at 1kHz
  • Extremely clear sound regarding Digital Direct Decoder and switched-sinewave stereo decoder
  • Very musical sound, highly recommended as the tuner in Hifi systems

Difficult, problematic items:

  • Just 8 memories for each band
  • The transformer is always connected to the power line, and with the 2 regulator transistors on heatsink generate a lot of heat to upset a careful alignment,
  • Has no signal-strength indicator
  • The IF bandwidth and mono/stereo settings are not saved along with frequency in the station memories.
  • The board must be unbolted and awkwardly tilted for modification because there is no bottom access
  • The memory pushbuttons often don't work due to decomposed foam between the front panel and switches
  • The soldering of connection multiwire cables and the display driver TD6301AR pins to PCB are very weak, can make malfunctions, is better if you resolder them - but I recommend to resolder all solder joints.

The tuner is very similar to the latest and famous F99X model, excepting the 2 IF amplifier stage, separate for Wide and Narrow IF circuit, for better selectivity. The F90 is a simple but good-sounding tuner. to greatly increase the modulation percentage, the IF signal is doubled to 21.4 MHz and then heterodyned to 1.26 MHz. This enhances S/N. The patented Digital Direct Decoder uses two proprietary ICs. One includes a pulse-count detector (PA5006). The decoder phase-locks a 38 kHz sine wave to the 19 kHz pilot. The pulses gate the sine wave to the left and right channels (the multiplication circuits are analog switches). Because the pulse rate is well beyond the spectrum of the composite stereo signal, no spurious mixing products result. In particular, the decoder is immune to HD Radio self-noise. The circuit includes pilot cancellation (PA5007). AM section uses a Sanyo LA1247, which has somewhat better performance than the usual LA1245.
As usual for such old tuners, was necessary to change all electrolytic capacitors.
Modifications:
Power supply: the power supply pass transistors (Q403 and Q405) originally are mounted on two heatsinks. They generate enough heat to significantly raise the internal temperature of the tuner, which can degrade the tuner's alignment, especially of ceramic filters. For this reason is recommended to be mounted both transistors on the rear panel, electrically isolated, to dissipate the heat outside (fortunately this was made by the previous owner). C374, C403 100uF/25V solid elcap; C406 and C410 330uF/50V Capxon; C412, C335, C513 220uF625V Rubycon; C368, C405 1000uF/35V Capxon; C23, C212 390uF/35V Rubycon; C325, C376, C404 changed to 2200uF/25V Rubycon.Inductances inserted into power lines: 100uH before C513 for TC9147P (PLL + control), 33uH for TD6104 (prescaller) after R501, 33uH for TD6301 (LED driver).
Signal: for this, I considered the F99X schematic:
AM: R506 replaced with 2 pcs of 1N4148, C217 removed (extends the high end response), C356 chnaged to 0,47uF foil Wima (improve the bass). C216 was removed from before C215 and moved after it.
FM: at doubler Q110 and Q111 have separated and same emitter circuit: added 560 ohms and 1000p styro. R309 was removed, L301 and L303 changed between each other. C336+C337 and C341+C342 were replaced with 1-1 of 3.3uF foilcap. R331 and R332 were replaced with 31.6kohms, C334 and C339 changed from 1.5nF to 2.2nF styrocap type.
Other recommended changes: changing the narrow circuit filters with low loss +-150kHz type (must be paired!), readjusting the stereo decoding matrix's R306 68kohms, adding a 100kohm trimpot, and should be adjusted for maximum separation.
Is a good tuner, a fine basis for improvements, and has a very good, pleasant sound on FM and also on AM. Is not as sensible, as comes out from specification, which means is not a DX tuner (with good antenna can be), but has a very musical sound, I like it.



RFT


The origin of all companies that produced radios in Leipzig was founded in 1925 by the businessman Oswald Ritter and the technician Wilhelm Dietz. The company initially produced transformers, power amplifiers and dynamic loudspeakers under license from the American company Magnavox. From 1932 radio receivers were added to the product range and the company in Körting Radio, Dr. Dietz & Ritter GmbH changed. With the models Cyclo-Super and Hexodensuper, their first superheterodyne receivers, also called superheterodyne receivers, came onto the market. In the course of arming the Wehrmacht, D & R built radio technology for the Air Force under license from Telefunken and Lorenz on behalf of the Reich Aviation Ministry (RLM) from 1935. In 1938 Körting Radio was one of the leading manufacturers in the market. The Leipzig radio equipment manufacturing facility was affiliated to the Berlin Löwe Radio AG in April 1941 as Löwe Radio AG, Leipzig plant. From August 1, 1942, the Löwe branch in Melscher Strasse was called the Leipzig plant, analogous to the parent company Opta Radio AG. With the financial means from the outsourcing of his Wehrmacht production, Ritter continued the radio receiver production as the sole owner of the old factory at Eichstädtstraße 11 (today Untere Eichstädtstraße) under the name "Körting-Radio-Werke Oswald Ritter". The Opta operation in Melscher Strasse was named Opta-Radio AG, Stötteritz plant with the status of a SAG (Soviet state company) and in 1948 became VEB Stern-Radio Leipzig. In 1952, after an internal profile change, the name was changed to VEB Fernmeldewerk Leipzig, which was now mainly dedicated to the production of telecommunications systems, but also z. B. Manufactured microphones. The former Körting Radio Werke Oswald Ritter in Leipzig were initially incorporated into the RFT-Funkwerk Leipzig VEB and in 1964 the VEB Fernmeldewerk Leipzig. With the formation of the Kombinate, this company received the status of the parent company of the VEB RFT Kombinat Fernmeldewerk Leipzig in 1970.

RFT Capri 6401 Stereo

RFT Capri 6401 St       RFT Capros 6401 St

Both of my grandfathers had this type of radio at Alsóbölkény (Beica de Jos) and Marosvásárhely (Neumarkst, Tirgu Mures) - in Transylvania, now part of Romania, and I always was fascinated by their sound. Is a stereo receiver (mono radio and stereo amplifier) made in 1963 by RFT (see below).

General information:

  • Principle: AM superheterodyne, with IF=460kHz, 9 RF circuits.
  • For FM: IF=10.7MHz, with 10 RF circuits
  • Manufacturer: RFT (Rundfunk- und Fernsehentechnik) at Goldpfeil Rundfunkgerätewerk Hartmannsdorf from DDR (East or Communist Germany)
  • Bands: in total 7 - LW: 150 - 410 kHz, MW: 510 kHz - 1.630 MHz, 4 SW bands (1.9-5.7Mhz, 5.65-10MHz, 11.5-18.2MHz, 18.1-26.4MHz) and one FM OIRT: 66-73MHz
  • Selectivity: AM 15-20uV/10dB, FM 3uV/30dB
  • Tubes: 10 pcs - ECC85, EF89, ECH81, 2xEBF89, 2xECC83, 2xEL84, EM84, 2 GE diodes: OA646, 1 Si diode: OA910 and 2 Selenium rectifiers: 1/2 B 250/200 - 0.15A
  • Power supply: alternating current, selectable 110-240V, 50Hz, 95W
  • Audio bandwidth: AM 40Hz-6kHz, FM 40Hz-18kHz, 2x4W
  • Speakers: 2 oval 18x25 cm for bass and middle in front and 2 tweeters 9 cm at lateral sides
  • Adjustable bass, treble and balance potentiometers, and 4 sound mode selector switches: speech, solo, jazz and x-bass.
  • Inputs: AM and FM antenna, tape recorder and turntable (crystal cartridge)
  • Dimension: 690x405x275 mm, 19.5 kg
Originally this radio has a possibility for upgrade: later, in the early '70s could be added an FM stereo decoder module made with transistors. This radio can be considered as the successor of famous Beethoven radio also made by RFT.
Modification: now has a power line socket with EMI filter + detachable power cable, and on DC filtering parts electrolytic capacitors were chanced with new ones.



Rotel


Rotel is a family-owned Japanese manufacturer of high-end audio and video equipment: home theater, amplifiers, compact disc players, etc. The company was established in 1961. In the early 1980s Rotel joined the B&W Group forming a strategic alliance with Bowers & Wilkins and later adding Classé Audio. The global affiliation between Rotel and the B&W Group dates back to the early 1980s with the establishment of exclusive distribution in North America and several European markets. Over the next 20 years, Rotel appointed virtually all Bowers & Wilkins distributors globally. In 2000 the B&W Group established Rotel Europe in the UK to consolidate all Rotel sales and support activities outside North America. The Classé brand was acquired by Sound United in 2018, breaking the link with B&W. Rotel maintains an exclusive network of specialist hi-fi dealers around the world.


ROTEL RX-850

Rotel RX-850

Is a receiver amplifier with a very warm sound from 1980's with exceptionally good overload characteristics.

General information:

  • Digital 2 bands (MW-FM) PLL radio without RDS capability,
  • 16 memory presets, 8 for FM and 8 for AM
  • Coverage: MW 520kHz - 1.611MHz, FM 87.5MHz - 108.0MHz
  • Channel space: 9kHz for AM and 50kHz for FM
  • Intermediate frequency: 450kHz for AM and 10.7MHz for FM
  • Usable sensitivity: 12uV on AM, 0.95uV on FM mono and 20uV for FM stereo
  • Integrated circuits: FM IF IC: LA1235, stereo decoder: LA3390, PLL freq. synthesizer: TC9147BP, FM prescaller TD6104P, DTS 6-8  display driver TC9158P, NE5532 OPA for RIAA
  • Output frequency response on FM: 30Hz - 15kHz (-1...+1dB)
  • Signal/noise ratio: AM 53dB, FM 82dB mono, 78dB stereo
  • THD: on FM 0.07% for mono, 0.25% for stereo
  • Stereo separation: 43dB
  • Antenna input impedance for FM: 75 and 300 ohm
  • Amplifier part: continuous power on 8 ohm: 30 W / channel, THD 0.03% (20...20000 Hz)
  • Amplifier input sensitivity: PHONO (MM) 2.5mV / 47 kohm; CD, VIDEO and TAPE 150mV / 4.7 kohm;
  • Amplifier input overload level: PHONO 200 mV (MM) and 5 V for other inputs
  • Amplifier frequency response: Phono 20...20000 Hz ±0.3 dB (RIAA STD), 20...30000 Hz +0..-1 dB from other inputs
  • Amplifier tone control: Bass 100Hz ±3.5dB, Treble 10kHz ±3.5dB
  • Amplifier signal to noise ratio (A weightened) 80dB for PHONO, 100dB for other inputs
  • Power: 220V/50-60Hz, consumption: 180W
  • Dimensions: 444x86x346mm, 7.0kg

Good things:

  • Has a very clean sound, beautiful bass, low noise and high FM selectivity
  • Has signal level indicator
  • Has a Postdetection Filter to eliminate HD FM radio noise (used in America)

Difficult, problematic items:

  • 2x8 preset memories are not enough, especially for FM
Considering its age, was necessary to change almost all electrolyte capacitors.



SABA


SABA (Schwarzwälder Apparate-Bau-Anstalt) originally was a German electronics company founded in 1923 at Triberg im Schwarzwald (Black Forest), present-day Baden-Württemberg. SABA started as a clock-making company, then became a radio manufacturer, and a few years later a record label. In 1968, SABA sold the majority of the company to GTE, an American telephone company. In 1980 the company was purchased by Thomson SA and integrated as a separate business unit.


Saba TS2030 RDS

Saba TS2030 RDS

Is an interesting tuner, without to many references on the net. Has RDS capability, a primitive one, with several operational amplifiers to filter the radio signal (57kHz), extract, and decode the RDS information with its own microcontroller (no dedicated integrated circuit are used!). Has remote control possibility, marked as CRC (Computerized Remote Control), and the last channel recall. The RDS data is visualized only on a 4 character display with scrolling characters, and shows just the station name.

General information:

  • Manufactured by Saba in Villingen in Germany in 1985.
  • Digital 3 bands (LW-MW-FM) PLL radio,
  • 29 memory presets on 3 pages for FM and AM
  • Coverage: LW 153kHz - 281kHz; MW 531kHz - 1.602MHz; FM 87.5MHz - 108.0MHz
  • Usable sensitivity: unknown
  • FM IF IC: LA1170, AM tuner IC: TDA1220B, stereo decoder: TEA5580, SAA1057 PLL syntheser IC, uController and display driver: uPD75216ACW/200, U2505B infra red remote control system IC.
  • Output frequency range: 20Hz - 15kHz (+0.5dB...-1.5dB)
  • Signal/noise ratio: unknown
  • THD: unknown
  • Stereo separation: unknown
  • Channel balance: unknown
  • Alternate Channel Selectivity (FM): unknown
  • Line output impedance: 10 kohm
  • Antenna input impedance for FM: 75 ohms
  • Power: 220V/50Hz, Consumption: 10W
  • Dimensions: 440x80x290mm, 2.7kg

Good things:

  • Discrete output amplifier instead of an operational amplifier IC
  • Last station memory - tuner switches on with the last station listened (at that time was a new thing), which is not necessary to be a saved one in memory
  • High quality of electrical parts used, especially in case of solid capacitors, coils

Difficult, problematic items:

  • No ferrite antena, the AM signal can be captured just via external antena
  • Has only 1 antenna input.
  • No signal level indicator
  • Everything is plastic, including the front side
The memory are kept via a Lithium battery soldered on control panel (CR2432). All electrolyte capacitors changed.



Sangean


Sangean Electronics, Inc. is a Taiwanese electronics company headquartered in Zhonghe District, New Taipei, Taiwan, with a factory located in Dongguan, China. Apart from products sold under its own brand names, which include Lextronix, Sangean also produces on behalf of other companies -> any of the shortwave radios marketed by Siemens, Panasonic, Braun, Grundig, C.Crane, and Roberts have been and are being developed and produced by Sangean. The organisation is globally active with business units in Venlo, The Netherlands for Europe and Santa Fe Springs, California for the Americas. The business units are directly in contact with distributors in relevant areas. It is noted for its shortwave radio receivers and digital radio (HDR and DAB/+) receivers.


Sangean DT-220

General information:

  • Manufactured: Sangean in Taiwan, Chung Ho city from 1998 till 2008
  • Digital 3 band (LW-MW-FM) PLL radio with RDS+EON capability, stereo with build in headphone/selectable, time and alarm function, auto scan and traffic info possibility
  • 25 memory presets: 16 for FM and 9 for AM
  • Coverage: LW 153kHz - 279kHz, MW 520kHz - 1.710MHz, FM 87.5MHz - 108.0MHz (stereo with headphones)
  • 9/10 kHz steps on AM (selectable), 50kHz on FM
  • Intermediate frequencies: 450kHz for AM, 10.7MHz for FM
  • AM/FM tuner circuit with stereo decoder: TA2104BFN, RDS decoder: SAA6579T, PLL circuit: TC9418FN, uController: uPD753012A and amplifier: CXA1622M
  • Signal/noise ratio 30dB on AM and 46dB on FM
  • Sensitivity: 60dBuV on LW, 52dBuV on MW, 12dBuV on FM, 18dBuV for stereo and RDS
  • Output power: 100mW in speaker or 2x5mW in headphones, THD 5% on AM and 3% on FM
  • Power: DC in 3V/300mA, or 2 AA (R6) batteries
  • Dimensions: 124x75x25.5mm, 169g without batteries

Problems:

  • Too high power consumption from batteries. A Sony radio with same capability could run 2-3 time longer with same power/batteries
  • The incorporated headphone wires lengths are too short, you cannot put the radio on your trousers pocket and in same time the headphones in your ears. To store the radio on your shorts pocket is very uncommon and heavy.
  • The physical dimensions are too big to be used in any pockets.
  • Selectivity is an average, not better
  • In my radio the LW parts components are not mounted, means cannot be used for LW band reception, but in manual are not described also how to switch to LW band.
  • Has just a simple RDS, cannot display Radio Text messages.
Generally is a good radio, but a bit overpriced.
At its time was one of the smallest receiver with RDS capability, used for RDS reception checking and signal transmission accuracy/level by Hungarian Radio authorities in 2000-2006.
One weakness is the volume potentiometer: rapidly became unusable giving scratch noise in the speaker. Temporary can be "refurbished" with contact spray, but is better if you change it asap (R-VR 20kA, partnumber: 1312014).
Some parts are also different from schematic: C44 instead of 220uF/6.3V is 470uF/6.3V, CF2 instead of Murata 10.7MS3 is L10.7S Chinese type.
Modifications: ceramic filter changed from L10.7S with a Murata 10.7MJ type, and all electrolytic capacitors, excepting the 2 audio output ones, were changed because of their high loss (>2%) and high ESR (>2 ohms) (after 9 years usage), with same capacitors value TA type (4,7uF/16V; 10uF/16V and 47uF/6.3V).



Sangean DPR-69+

Sangean DPR-69+

Is a low-cost table radio with RDS/radio text on FM and DAB+ capability. From 2018 are sold in Europe under the name TRAVELLER 690.

General information:

  • Made by Sangean between 2010 till 2018
  • Digital 2 bands (FM and DAB+) DSP radio with RDS and Radio Text capability (PS, PTY, CT, and RT),
  • 5+5 memory presets, 5 for each band
  • Coverage: FM 87.5MHz - 108.0MHz, DAP+ (Band III, channels 5A - 13F) 174.928MHz - 239.000MHz
  • Channel space: 50kHz for FM and not known for DAB
  • From the menu can be selected the Local/DX reception
  • Integrated circuits: digital radio module from Frontier Silicon Kino3 FS2027, NJM2100 preamplifier and filter, MC33340 charger, PT2308 headphone amplifier, TPA2005D1 D class amplifier for speaker, Atmel 0726 EEPROM, CD4013 as switch circuit.
  • Stereo just via headphone
  • Built in speaker: 8 ohm/0.3W (in specifivation are rated 0.5W), 75mm
  • Power: from 4xLR6 (AA size) batteries or 4xNiMH rechargeable, or from an external power supply 7.5V/800mA (+ at middle) which can charge the NiMH accumulators in selected charging mode.
  • Dimensions: 161 x 106 x 37mm (W x H x D)
  • Weight: 348g without battery
  • The box contains: the radio + user manual + external power supply (PWM)

Good things:

  • Selectable Local or DX mode. Selectivity is quite good.
  • RDS with Ratio text
  • NiMH charging
  • Selectable Auto/Manual searching mode
  • Lock switch

Difficult, problematic items:

  • Just 5 stations presets/band
  • Buttons are rubber-coated with lacquer
  • A bit slow wake-up after turn on
  • High power consumption (less than 25 hours), is better if you use it from an external power supply
  • The antenna doesn't pop out so you can have it vertical while lying the radio on its back
  • The radio's house is very shiny and because I have the black version, any fingerprint can be seen on it.
In several advertisements are mentioned has USB B connector on the left side, above the headphone jack, for software (firmware) upgrade, and this is also mentioned on the original package of radio, but my sets haven't. My radio's software version: dab-mmi-FS2027-0000-0050_V4.0.13.27373-5.
Inside the capacitors were manufactured by GD (China), SH7 type, 105 C. All are in good condition (my set was made at end of 2016).
Not so many articles or reviews can be found about this radio, neither service manual. Look similar to Sangean DPR-67. As a guideline, I used the service manual of Sangean DPR-99 (construction, units are the same, but use different integrated circuits).
Is overpriced, in 2021 the unit is sold for 79-110 Euro, on the used market costs 20-40 Euro.


Sangean ATS-909X

Sangean ATX-909X

Sangean released it in 2011 as an upgrade of ATS-909 (identical with Radio Shack DX-398). Although the model name is similar, the radio received a complete redesign in and outside. Has a new face, big screen with full backlight, DSP, built-in charger, Aux-in jack, priority button, separate built-in headphone amplifier, ATS (auto scan tuning) function (excepting SW), squelch function (background noise level decreasing, works just on AM), alarm, snooze, SSB reception possibility, external antenna jack (for SW), record line out, AM RF gain adjust, etc.

General information:

  • Manufactured: Sangean in Taiwan, Chung Ho city from 2011 till 2020 (now are replaced by ATS-909X2 model)
  • Digital 4 band (LW-MW-SW-FM) PLL radio with RDS+EON capability, stereo with headphone, time and 3 alarm function,
  • Has auto scan, called ATS: Automatic Tuning System.
  • 406 memory presets: 27 for FM, and 9 for LW, 18 for MW, and 351 for SW - each one on pages with 9 preset/page.
  • Coverage: LW 100kHz - 519kHz, MW 520kHz - 1.710MHz, SW 1.711MHz - 29.999MHz, and on FM 76MHz - 108.0MHz (stereo with headphones)
  • Tuning steps (Fast/Slow): FM 100kHz/50kHz, LW 9kHz/1kHz, MW 9 or 10kHz/1kHz, SW 5kHz/1kHz, LSB/USB 1kHz/40Hz,
  • Intermediate frequencies: IF1 450kHz, IF2 55845kHz for AM, 10.7MHz for FM
  • DSP SI4735; AM IF TA7640; aux audio in switch TC4066; headphone amplifier PT2308 (=TDA1308); NJM2073D speaker amplifier; preamplifier NJM2100; battery charge controller MC33340; voltage regulators: XC62AP3002PRN and LD1117AL-Adj; 8bit microcontroller uPD78F0513A; eeprom: 24L32A; keypad interface and display driver AP650; 1.1GHz PLL frequency Synthesizer MB15A01
  • No any other official specifications are available
  • Output power: 1W on a speaker of 3" 8 ohm 3W
  • Power: AC 9V/700mA, or 4 AA (R6) batteries, or 4 NiMH accumulators (automatic charging is selectable (in battery compartmnet via Alcaline/NiMH charging switch)
  • Dimensions: 207x134x41mm, 169g without batteries

Remarks:

  • Has a very pleasant sound, especially on FM
  • Has a 10 bar signal strenghts metter,
  • The physical dimensions are too big to be used in any pockets.
  • Selectivity is very good on FM, good on LW/MW/SW
  • The frequency ranges depend by model. Some has SW just till 26MHz, and FM starts from 87.5MHz,
  • Has just a full RDS, but cannot be programmed to display automatically for eah station the Radio Text messages, just if you select it.
  • Also in battery compartment is the tunning step swith for AM 9/10 kHz, which during battery insertion easily can be switched by mistake in other position



Sansui


Sansui Electric Co., (Sansui Denki Kabushiki-gaisha) was a Japanese manufacturer of audio and video equipment. The company was founded in Tokyo in 1947 by Kosaku Kikuchi, who had worked for a radio parts distributor in Tokyo before and during World War II. Due to the poor quality of radio parts Kikuchi had to deal with, he decided to start his private radio part manufacturer facility in December 1944 in Yoyogi, Tokyo. He picked transformers as his initial product line. Kikuchi's thought was "Even with higher prices, let's make the higher quality of products." In 1954 manufacturing Pre-Amp, Main-Amp kits, as well as finished amplifiers which used tubes, was started; in 1958 Sansui introduced the first stereo tube Pre- and Main amplifiers. By the 1960s Sansui had developed a reputation for making serious audio components. They were sold in foreign markets through that and the next decade. As the mid-1980s arrived, sales were lost to competitors (Sony, Pioneer, Matsushita's Technics). Sansui began to lose visibility in the United States around 1988 and then focused on manufacturing high-end components in Japan. The company began to manufacture high-end television sets and other video equipment but ceased exportation. Sansui ended its Japanese production of high-end amplifiers sometime between 2002 and 2005 and went out of business in 2014. In Japan, consumer product maker Doshisha has the right to manufacture and sell under the Sansui brand. Outside of Japan, the brand belongs to Nimble Holdings of Hong Kong.


Sansui T-500L

Sansui T-500L

Is a nice tuner from the lowest family of System IS, part of IS-500. Its specification (excepting the quieting sensitivity at 50dB, which is 17.0dBf, compared to 16.5dBf) all specifications are the same with the higher family tuners, the T-700 and T-900. The pointer light's color is the tunning indicator: during searching is red, but if the tuner is rightly on the station, became green. The tunning knobs' blue backlight is phenomenal.

General information:

  • Manufactured at 1980 by Sansui Electric Co. Ltd., 14-t Izumi 2-Chome, Suginami-ku, Tokyo 168, Japan; Made in Japan
  • 3 band analog PLL tuner LW, MW, and FM
  • Coverage: LW 150 - 350 kHz, MW 530 - 1600 kHz, FM 88 - 108 MHz
  • Antenna input impedance for FM: 300 ohms balanced / 75 ohm unbalanced,
  • Usable sensitivity: 398uV/m on MW, 1000uV/m on LW, 0.9 uV on FM (mono), for stereo not specified,
  • Signal to noise ratio: mono 75dB, for stereo 70dB,
  • Distortion at 65dBf at 1000Hz: for mono 0.15%, for stereo 0.2%,
  • Intermediate frequencies: 455kHz for AM, and 10.76MHz for FM,
  • AM tuner IC: LA1240 amp, osc, IF and det; FM det. LA1231; stereo decoder (MPX) BA1332; tunning indicator BA6137,
  • Output frequency range:30Hz - 15kHz (-1.5...+1.0dB),
  • Power: ~220/240Vac, 50/60Hz, consumption 8W,
  • Output level and impedance: 600mV/2.2kohm,
  • Dimensions: 430x78x233mm, 2.5 kg.
Has a pleasant warm sound, selectivity is quite good. Has one problem: the muting level is too high, should be readjusted.
To be considered: no fuses are mounted inside of the tuner (they are shorted with wire). The transformer is continuously connected to the power supply, and the power switch connects only one secondary coil's voltage to the tuner circuit. The mQ1 regulator transistor stabilizes the input DC voltage from 18.5V to 13.5V - and the heatsink remains almost cool after several hours of operation.
Modifications:
Power circuit: mC3 from 470uF/25V to 2200uF/25V, mC4 from 330uF/16V to 470uF/35V, mC5 from 10uF/16V to 390uF/35V, dC36 from 220uF/16V to 470uF/35V, eC24 from 100uF/16V to 330uF/16V.
All electrolites from the signal line were changed to polypropilene. The audio output capacitors (mC48L and mC48R) value was changed from 0.15uF/100V to 0.47uF/63V. Other below 10uF were changed to solid electrolites or tantal capacitors.
The tuner is built from modules, like AM IF module, FM IF module, MPX module, signal level meter module, etc, and all are soldered to baseplate - not via sockets! This is a cheap solution but is a nightmare if you would like to repair any of them or to change all electrolytic capacitors. On the base plate are no components, just soldered modules. The straps which connect them are printed on the soldering side, on the top side can be seen a drawing of patterns from the bottom side, making it easy to recognize the trace. Also, the tuner has an electrolytic, which can be changed without desoldering the whole unit from the baseplate, because below the tuner module the baseplate has a cropped part, which easily can be permanently removed. The removed area has no trace or coverage with cupper - but by removing it you can change only one 10uF/50V capacitor from the tuner module.



Sharp

/ Optonica


Sharp Corporation was founded in 1912 in Tokyo by Tokuji Hayakawa as a metal workshop. In 1923 the company was relocated to Osaka and began designing the first generation of Japanese radio sets. The company was established as "Hayakawa Metal Works" in 1924, in Tanabe-cho, Osaka. In 1942, the name was changed to "Hayakawa Electric Industry Company". The Optonica brand was created and first launched by Sharp in 1976 to compete in the high-end audio market along with established brands such as Sansui Electric, Sony, Panasonic, Sanyo, Yamaha, Nakamichi, Onkyo, Fisher Electronics, Technics (brand), Pioneer Corporation, Kenwood Corporation, JVC, Harman Kardon, and Marantz. The brand was designed and built by Sharp, not contracted out to another supplier, and all of the items offered were of high quality standards and built in Japan. Sharp Corporation was responsible for marketing the products. Marketed for a few years, the line and brand were discontinued in 1991.


Sharp Optonica ST-1122H

Sharp Optonica ST-1122H

General information:

  • Manufactured at 1978 by Sharp Corporation Japan in Osaka
  • 3 band analog superheterodyne tuner, LW, MW and FM
  • Coverage: LW 150kHz - 370kHz, MW 520kHz - 1.620MHz, FM 87.6MHz - 108.0MHz
  • Antenna input impedance for FM: just 300 ohms balanced,
  • No preset memory for FM
  • Usable sensitivity: 350uV/M for LW, 450uV/m for MW and 2.0 uV on FM mono (stereo not specified)
  • Intermediate frequencies: 455kHz for AM, and 10.7MHz
  • AM RF/IF amp and detector IC: RH-IX1032AFZZ (HA1151), FM IF amp and Quadrature detector 91TLA-1230B (LA1230B), PLL MPX Demodulator 91TLA-3350 (LA3350).
  • Signal to noise ratio: mono 60dB, stereo and for AM not specified
  • Harmonic distortion: mono 0.5%, stereo not specified, and 1.5% for AM
  • Output frequency range: 40Hz - 15kHz (-2...+2dB)
  • Power: ~110/220/240V/50Hz, consumption 7W
  • Output power: 350mV on FM and 200mV on AM
  • Dimensions: 390x142x257mm, 4 kg.

Good things:

  • Has air check capability (see the description at Fisher FM3210 tuner) with 400Hz signal at the output
  • Has very special legs, with jelly balls inside which eliminate any vibration
  • Good sensitivity and selectivity on FM
  • Long scale and the tunning knob runs extremely smoothly

Problematic things:

  • Has no signal output connector. The signal comes out on a cable with a DIN socket on the end. I changed it immediately to have RCA L+R, used in my system.
  • AM and FM antenna socket is very uncommon, difficult to find. I inserted just the end of wire into them as antenna.
  • No unbalanced (75 ohms) antenna input, but for that can be used the left signal input of 300 ohms antena socket with the ground (from AM antena connector)
  • No backlights for meters and scal. Was necessary to install it
This tuner was a big surprise for me, I did not expected to be so good. The reception is quite sensible, warm sound, but has less room and bass on bottom side of audio band. All electrolytic capacitors changed.



Siemens


Siemens & Halske was founded by Werner von Siemens and Johann Georg Halske on 1 October 1847. In 1848, the company built the first long-distance telegraph line in Europe; 500 km from Berlin to Frankfurt am Main. In 1867, Werner von Siemens described a dynamo without permanent magnets. A similar system was also independently invented by Ányos Jedlik and Charles Wheatstone, but Siemens became the first company to build such devices. In 1881 the company continued to grow and diversified into electric trains and light bulbs. Siemens & Halske (S & H) was incorporated in 1897, and then merged parts of its activities with Schuckert & Co., Nuremberg in 1903 to become Siemens-Schuckert. In 1919, S & H and two other companies jointly formed the Osram lightbulb company. During the 1920s and 1930s, S & H started to manufacture radios, television sets, and electron microscopes. In the 1950s, and from their new base in Bavaria, S&H started to manufacture computers, semiconductor devices, washing machines, and pacemakers.
Siemens AG today is a German multinational conglomerate and a focused technology corporation headquartered in Munich and the largest industrial manufacturing company in Europe with branch offices abroad. The principal divisions of the corporation are Industry, Energy, Healthcare (Siemens Healthineers), and Infrastructure & Cities, which represent the main activities of the corporation.


Siemens RH777

Siemens RH777

This tuner was the top model in 1979 of Siemens, part of a 6 pcs system, called System 777 (other components: RC777 three heads microprocessor control cassette deck, RW777 pll quartz-controlled direct-drive turntable, RF777 infrared remote controller and timer, RP777 stereo preamplifier and RE777 stereo power amplifier). The whole system, without the turntable, cost 3,995 DM at 1979! Just the tuner price was 748 DM. The tuner inside has a lot of Sanyo components, and also on several webpages are highlighted as OEM Sanyo - but I did not find the same Sanyo tuner. The FM tuner input stage is the same as Sanyo T55, or Sanyo T33.

General information:

  • Manufactured: by (or for?) Siemens in Japan between 1979-1973
  • Digital 2 bands tuner with remote possibility, stereo with headphone, time and alarm function
  • 16 memory presets: 8 for FM and 8 for AM
  • Coverage: MW 516kHz - 1.605MHz, FM 87.5MHz - 108.0MHz
  • Sensibility: 0.7uV for FM mono, 31uV for FM stereo
  • THD: 0.2%
  • Stereo channel separation: 35dB
  • Frequency response: 20-15000 Hz
  • Signal to noise ratio: FM mono 70dB, FM stereo 60dB, and for AM not specified
  • Intermediate frequencies: 458kHz for AM, 10.7MHz for FM
  • AM tuner circuit: LA1130; FM IF amplifier: AN278; FM IF: HA11225; core cpu: SMC6200A; LED display drivers: BA612 and BA618 (2 pcs); signal meter: TL489, noise canceling circuit: TA7324; MPX decoder: uPC1161; CMOS RAM TC5501; prescaller HD10551; microcontroller: S871; PLL synteser: MSM5806; voltage regulators: FS7805 and FS7806M; logic circuits: TC4001, TC4081 (7 pcs), TC4069
  • Antenna input: 300 ohms balanced, 75 ohms unbalanced, for AM just external (no ferrite rod antenna)
  • Intermediate frequency suppression: better than 90dB
  • Output signal level and impedance: 700mV / 4kohm
  • Power: 220Vac/50-60Hz
  • Power consumption 15W
  • Dimensions: 440x545x300 mm
  • Weight: 5kg

Good things:

  • Very logical design
  • Good selectivity and sensitivity on FM
  • Robust structure, well separated the power and controller part from the tuner part

Problems:

  • Has 2 transformers, one is permanently connector to the power line - supplying the CMOS RAM
  • No internal ferrite antenna. AM can listen just with an external one
  • Audio output socket is DIN type, nowaday rarely used
  • Internal stiffeners of chassis, especially at cable glands, has burrs and the cable packs have no extra protection.
  • The signal level indicator is very deep situated in the front panel, can be seen just if they are on your eye level or from a distance
Considering, this radio appeared on the market in 1979, had the newest technology from that era: auto scan, channel number display, channel scan, slow and fast manual tunning, 16 preset memory locations, 8 for FM and 8 for AM, dual-gate MOSFET FM input stage, 4 gang FM tuner, 4 ceramic filters (2 + 2 in series), output buffer after MPX decoder, special muting circuit, microprocessor control, PLL synthesizer circuit with CMOS RAM, powered with NiCd accumulators, which still works well! After 42 years from manufacturing, the radio has just a few components that were necessary to be changed: the relay to switch on the main transformer, and some electrolytic capacitors with still work but had high ESR value.
Differences from service manual: all 3 main PCBs (control with power supply, subboard and the tuner board) look like a product in design phase, with plenty of posibilities, unmounted but numbered parts which are missing from schematics. They are not different models with new functions. Only one edditional component I found, with no position number: a 0.1uF tantalum capacitor between pin3 of IC5 (TA7324) and ground.
Modifications: instead of C86 and C87 (both 4.7uF in series connection) I mounted 2.4uF pp capacitor, and also instead of C88 and C89, both were 1uF connected in series, I mounted 0.49uF pp capacitor. In several position in th power line I increased or kept their values, but I mounted solid electrolyte capacitors.
In audio signal path I mount pp capacitors, just at output their values were increased from 2.2uF to 4.7uF.


Siemens RK 747

Siemens KR747

This is an interesting world receiver - was also manufactured under brand name Sangean PT-633 (Pro Traveller) by Chinese factory (like many other Siemens small receivers) and Grundig Yacht Boy 218. The full model name is RK747 G6. Can be set the time zones, alarm, tuning LED, adjustable sleep timer, stereo/mono switch, lock switch.

General information:

  • Manufactured: by Siemens D (S.& Halske / S. Electrogeräte) GmbH at 1996
  • Analog 9 band (SW-MW-FM)radio with 7 SW bands, stereo with headphone, time and alarm function
  • No memory presets
  • Coverage: MW 530kHz - 1.710MHz, FM 87.5MHz - 108.0MHz (stereo with headphones)
    • Shortwave bands:
    • SW1: 5900 - 6200 kHz, 49 m
    • SW2: 7100 - 7350 kHz, 41 m
    • SW3: 9400 - 9900 kHz, 31 m
    • SW4: 11600 - 12100 kHz, 25 m
    • SW5: 13570 - 13870 kHz, 21 m
    • SW6: 15100 - 15800 kHz, 19 m
    • SW7: 17480 - 17900 kHz, 16 m
  • Intermediate frequencies: 450kHz for AM, 10.7MHz for FM
  • AM/FM tuner circuit with stereo decoder: TA8122AN; amplifier: TA7376P; core cpu: SMC6200A; high precision voltage regulator: S81230
  • No any other data in user or service manual
  • Output power: 150mW in speaker or 2x10mW in headphones
  • Power: DC in 4.5V/200mA (negative pole inside), or 3 AA (R6) batteries
  • Dimensions: 145x86x31 mm, 320g without batteries (450 with)

Good things:

  • Low power consumption
  • Good selectivity and sensitivity on FM, the rest of bands is jut average
  • Has a stand, and using it can stay very stable on desk

Problems:

  • To heavy to be a pocket radio
  • The sound regarding low speaker size (50 mm) is very sharp, but is good with stereo headphones
Is a good radio on FM, but on MW and all SW bands are not as good as Sony or XHData. Like other analog multiband receivers, the band selector switch is the heart of radio - must be maintained sometimes with contact spray. Despite its "young age", is better if all electrolytic capacitors are changed.



Sony


In 1946, Masaru Ibuka started an electronics shop in Shirokiya, a department store building in the Nihonbashi area of Tokyo. On 7 May 1946, Ibuka was joined by Akio Morita to establish a company called Tokyo Tsushin Kogyo (Tokyo Telecommunications Engineering Corporation). The company built Japan's first tape recorder, called the Type-G. In 1958, the company changed its name to "Sony". The name "Sony" was chosen for the brand as a mix of two words: one was the Latin word "sonus", which is the root of sonic and sound, and the other was "sonny", a common slang term used in the 1950s America to call a young boy. In 1950s Japan, "sonny boys" was a loan word in Japanese, which connoted smart and presentable young men, which Sony founders Akio Morita and Masaru Ibuka considered themselves to be. At the time of the change, it was extremely unusual for a Japanese company to use Roman letters to spell its name instead of writing it in kanji.
Sony played a major role in the development of Japan as a powerful exporter during the 1960s, till today. It also helped to significantly improve American perceptions of "made in Japan" products. Known for its production quality, Sony was able to charge above-market prices for its consumer electronics and resisted lowering prices.
Sony's TR-63 radio "cracked open the U.S. market and launched the new industry of consumer microelectronics. By the end of 1968 Sony, in one year, sold more than 5 million units of portable transistor radios in the USA.
As a major technology company, it operates as one of the world's largest manufacturers of consumer and professional electronic products


Sony STR-7055A

Sony STR-7055A

This is a nice Sony receiver from 1976, an improved version of STR-7055, and younger brother of STR-7065A. Was one of the biggest sales successes of Sony hifi in the seventies. Has a very beautifull front, seems to be built for eternity. The frontend and the mixer are with FETs, use 7 ICs, 48 transistors and 32 diodes. Are equiped with Loudness switch, High and Low filters (Off, High, Low or Both), Muting switch, Mode switch (Reverse, Stereo, L, R or L+R/mono), Monitor (can be selected Tape 1 & 2 as source), Speaker selector (can be selected between 3 pair of speakers: Off, A, B, C, A+B and A+C), Bass and Treble adjustment (can be adjusted together or separated both channels), Function switch (Aux, Phono, FM, AM, Tape1 to 2, Tape2 to 1 copy) and via a switch on back side the preamplifier can be disconnected/separated from amplifier (Separated/Normal). The Aux input sockets can be found on back and front side. The model 7065A has a higher power output (70W instead of 40W), and a microphone input which can be mixed into amplified signal. The difference between model 7055 and 7055A: the model A has an improved selectivity and sensibility of tuner. My version is Type I (differs from Type II from selectable AC power, AM IF is 468kHz and a bit less output power; and Type III operates just from 120Vac power line with permanently attached power cord, and the dimension of chasis is different: 471 x 157 x 375 mm, bigger than Type I or II).

General information:

  • Manufactured between 1976-1977 by Sony, made in Japan
  • 2 band analog superheterodyne receiver, MW and FM
  • Coverage: MW 530kHz - 1.605MHz, FM 87.5MHz - 108.0MHz
  • Antenna input impedance for FM: 300 ohms balanced, 75 ohms unbalanced,
  • Antena for AM: build in ferrite core and external terminal
  • No preset memory for FM
  • Usable sensitivity: 1.6 uV on FM mono, no data for FM stereo; 30uV on AM
  • Intermediate frequencies: 455kHz for AM, and 10.7MHz for FM
  • Used ICs: FM IF amplifiers: CX-0412 2 pcs; MPX decoder HA1156; operational amplifiers CX-0462 4 pcs (the service manual indicate in this position CX-0461, but are same)
  • Signal to noise ratio: FM mono 70dB, AM 50dB
  • Output frequency range on FM: 30Hz - 15kHz (+-1dB)
  • Stereo separation (at 400Hz): 43 dB
  • THD: 0.2% for FM mono, 0.4% FM stereo, 0.8% for AM
  • Power output: 40W/8 ohms
  • Bandwidth: 10-100kHz within +0 dB...-1dB, with 0.1% THM at 1W/8ohms; 15-35kHz +-1dB 0.2% THM at 35W/8ohms
  • Damping factor: 50 at 8 ohms
  • Phono sensitivity/impedance: 2.0mV/47kohms, RIAA +-1dB
  • Phono Overload: 100mV RMS 1kHz 0.1% THD
  • RIAA curve deviation: +-0.5dB, 30...15kHz
  • Tape Play/Rec and Aux inputs sensitivity/impedance: 250mV/50kohms
  • Preamplifier output: 1V/4.7kohms; Amplifier input: 1V/50kohms
  • Bass control: +-10dB at 100 Hz
  • Treble control: +-10dB at 10 kHz
  • High Filter: 12dB/octave at 9kHz
  • Low Filter (Subsonic): 12dB/octave at 50Hz
  • Loudness: +10dB at 50 Hz and +4 dB at 10 kHz, attenuation 30dB
  • Signal to noise ratio: Phono 72dB, Tape1&2/Aux 90dB, Power amp 100dB
  • Power: 110V/120/220/240V 50/60Hz, consumption max. 320W
  • Dimensions: 471x157x375 mm, 15.3 kg.

Good things:

  • Has a very clean sound, brave bass
  • Has a separate transistor buffer at output instead of direct signal from MPX IC or via operational amplifier
  • Very good sensitivity and selectivity on FM, high stereo sensibility, good stereo space
  • Aux input on back and front panel
  • The preamplifier-amplifier can be separated via switch and both has RCA connectors

Difficult, problematic items:

  • No signal strength meter on front panel (7065A model has)
  • Difficult to repair regarding cable-jungles and PCB panels arrangement inside
With more than 44 years, is a receiver with a very pleasant sound. Was necessary to change all electrolytic capacitors, all bulbs, and to make fine adjustments after capacitors change (at MPX). The scale pointer, the Stereo indicator and the tuning meter backlight were replaced with LEDs. Power lines were improved (output buffer of MPX LC filter). Capacitors in signal path were changed to foil/PP type.
The radio on AM are with 2 gangs, on FM are with a 4-gangs variable capacitors, two IF amp stages, 2 pcs of 10.7MHz ceramic filters, and a Sony-made low-pass filter at radio output. At that time the new unit price was 1198 DM.


Sony STR-4800

Sony STR-4800

This receiver is in the middle of series of STR-2800 to STR-6800 from 76-78s. The Sony STR-4800 combines a high-performance stereo tuner and a powerful amplifier with a host of facilities, like a combined oscillator and tuning capacitor for high stability and accuracy, uniphase IF filter for high selectivity and low distortion, phase lock loop stereo decoder for high channel separation and low distortion, long linear tuning scale for ease of tuning, Tape1 to Tape2 copying facility. On the front panel you can find: A and/or B speaker selection switch, output for headphone, low and high filters switches, bass-, treble-, and balance control, low-, presence-, and loudness control, FM muting and mono switches, monitor switch for Tape1, Tape2 and copy from Tape1 to Tape2, function switch: phono, FM, AM and Aux, audion muting switch with -20dB, and AUX input also on the front panel.

General information:

  • Manufactured between 1976-1979 by Sony, made in Japan
  • 2 band analog superheterodyne receiver, MW and FM
  • Coverage: MW 530kHz - 1.605MHz, FM 87.5MHz - 108.0MHz
  • Antenna input impedance for FM: 300 ohms balanced, 75 ohms unbalanced,
  • Antena for AM: build in ferrite core and external terminal
  • No preset memory for FM
  • Usable sensitivity: 1.7 uV on FM mono, no data for FM stereo; 250uV/m with ferrite antenna, and 100uV with an external aerial antenna on AM
  • Intermediate frequencies: 455kHz for AM, and 10.7MHz for FM
  • Used ICs: FM IF amplifiers: HA1137W 2 pcs; MPX decoder HA1156; teh Dolby are made with 2 pcs of noise cancelling operation amplifier CX064 (this is not mounted in my set, all related component positions are empty on tuner PCB); power amplifier SS050A (2 pcs),
  • Signal to noise ratio: FM mono 73dB, AM 50dB
  • Output frequency range on FM: 40Hz - 12.5kHz,
  • Stereo separation: 40 dB
  • THD: 0.2% for FM mono, 0.4% FM stereo, 0.5% for AM
  • Power output: 35W/8 ohms or 45W/4 ohms
  • Bandwidth: 10-35kHz within +0 dB...-1dB, with 0.1% THM at 1W/8ohms; 15-35kHz +-1dB 0.2% THM at 35W/8ohms
  • Damping factor: 35 at 8 ohms
  • Phono sensitivity/impedance: 2.5mV/50kohms, RIAA +-0.5dB
  • Phono Overload: 100mV RMS 1kHz 0.1% THD
  • RIAA curve deviation: +-1.0dB, 30...15kHz
  • Tape Play/Rec and Aux inputs sensitivity/impedance: 250mV/100kohms
  • Preamplifier output: 1V/4.7kohms; Amplifier input: 1V/50kohms
  • Bass control: +-10dB at 100 Hz
  • Treble control: +-10dB at 10 kHz
  • High Filter: 6dB/octave at 6kHz
  • Low Filter (Subsonic): 6dB/octave at 35 Hz
  • Loudness: +10dB at 50 Hz and +3 dB at 10 kHz,
  • Signal to noise ratio: Phono 70dB, Tape1&2/Aux 90dB,
  • Power: 110V/120/220/240V 50/60Hz, consumption max. 420W
  • Dimensions: 490 (W) x170 (H) x415 (D) mm, 13.9 kg.

Good things:

  • Has a very nice, classical front panel, with green color
  • The muting switch near the volume knob can decrease the volume with -20dB

Difficult, problematic items:

  • Some components are difficult to be found, like the Dual-C power capacitor made by Nichicon with 2x4700uF/50V in one can with 3 terminal (+2 unconnected). This capacitor was dryed, measured values 3500uF and 2900uF
The construction of the receiver is very stable and is easy to repair: all PCBs are fixed via 2-3 screws on one side, and on the other are inserted in positioning holes of chassis. If you open the metallic frame with the PCB of the power amplifier and RIAA, and a metallic shield that isolates the radio from the audio part, you will have access to the radio PCB from the soldering side.
The ceramic filters are Murata type, SFJ10.7MA with 4 terminals and blue dot (10.67MHz). The transformer is well shielded, without noise. The volume potentiometer was necessary to be replaced, sometime gives scratchy noise.The scale pointer was made with LED, which is a miracle at that time!
The capacitors were mostly Sam Wha type, and just a few of them were Korean Chemical Com. I bought it with one amplifier channel dead. Root cause: one capacitor from the amplifier feedback network was dead (instead of 100uF I measured 2nF, completely dryed). For that and regarding passed 45 years, all electrolytes were changed. The first time I used dry electrolyte capacitors in the audio stage (470uF/6.3V, Oscon), and they does not influence the overall sound impression.
At that time the new unit price was 1120 DM.


Sony ST-JX3L

Sony ST-JX3L

General information:

  • Manufactured in 1982 by Sony Tokyo
  • 3 band analog PLL tuner LW, MW, and FM
  • Coverage: LW 153 - 344 kHz, MW 522 - 1602 kHz, FM 87.5 - 108.0 MHz
  • Antenna input impedance for FM: 300 ohms balanced, 75 ohms unbalanced,
  • No preset memory for FM
  • Usable sensitivity: 60uV on AM, 1.4 uV on FM (mono) and 40 uV for stereo
  • Intermediate frequencies: 450kHz for AM, and 10.7MHz for FM
  • AM tuner IC: LA1245 amp, osc, IF and det; FM det. LA1235; AFC uPC4558C; stereo decoder (MPX) LA3390; signal indicator LB1416; and one double amplifier inside FM tuner which cannot be clearly identified
  • Output frequency range: 30Hz - 15kHz (+0.3dB...-2.0dB)
  • Signal/noise ratio: AM 54dB, FM 85dB mono, 80dB stereo
  • THD: on FM 0.08% for mono, and 0.12% for stereo
  • Stereo separation: 50dB
  • Channel balance: 0.2dB
  • Power: ~220V/50Hz, consumption 12W
  • Output power: 750mV/4.7kohm
  • Dimensions: 430x55x337mm, 3.4 kg.
Has an average sound, selectivity is good, but the output load should be higher than 1.9kohm because if is less, the audio level drops and the noise will increase.


Sony ICF-7600AW

Sony ICF-7600AW

Is a predecessor of the famous Sony ICF-7600, looking very similar, but sporting a lot of major and minor improvements under the hood. Appearing the dual conversion concept on shortwave (before was very unconventional) and received a total of seven shortwave bands with increased band coverage. Selectivity and sensitivity on mediumwave and shortwave also is very good, along with decent overload rejection. The effective tone control and nice audio section and speaker were taken over from the previous model, and power consumption remained low.

General information:

  • Analog shortwave portable (dual conversion):1st IF: 10.700 MHz; 2nd IF: 455 kHz
  • Coverage: MW 530-1605kHz, FM 76 - 108MHz (the W mark means West version, and those have a shorter FM band: 87.5-108MHz)
  • SW are not continuous, are divided in 7 bands:
    • SW1: 5950 - 6200 kHz, 49 m
    • SW2: 7100 - 7350 kHz, 41 m
    • SW3: 9500 - 9800 kHz, 31 m
    • SW4: 11700 - 12000 kHz, 25 m
    • SW5: 15100 - 15450 kHz, 19 m
    • SW6: 17700 - 17900 kHz, 16 m
    • SW6: 21450 - 21750 kHz, 13 m
  • No memory preset possibility
  • FM filters: 1x 280 kHz (super wide, but can be changed to 180/150 kHz low loss type)
  • FM/AM front end+IF discri&amp HA12413, power amp uPC1212C
  • Output impedance and power: 8 ohm 350 mW max @ 10% distortion
  • Dimensions/weight: 180 x 120 x 35 mm, 448 g (incl. batteries)
  • Power: four AA batteries or external 6V (minus is the center pin!)
  • Produced: 1982 ... 1988, replaced by Sony ICF-7601

Good things:

  • The noise level on MW and SW is very low
  • Very good selectivity and sensitivity on all bands
  • The dual conversion design does result in a smaller number of unwanted ghost signals that you find on single conversion sets in this price range, but is not as good as in as started from ICF-SW7600
  • very low power consumption (more than 40 hrs with conventional AA batteries).

Problems:

  • No light to illuminate the scale
  • No external antenna connection possibility
  • No provision for single-side band
  • The headphone jack is just mono, with a stereo jack you can hear just in the left speaker.
  • The band selector switched are the headacke of this model. After certain time must be changed.
Remark:
My set was made in Japan, inside of set and also on the package box has the same serial number (125792), but the FM coverage is 76-108MHz. That means should be an ICF-7600A model instead of ICF-7600AW. This makes it difficult to set the radio to a certain frequency because the scale is marked from 88 to 108MHz. An expert user after several scans of the FM band will not make difficulties this declaration.


Sony ICF-7601L

Sony ICF-7601L

Is also a predecessor of the famous Sony ICF-SW7600, and the successor of ICF-7600A, but compared with that has more SW bands. With the ICF-7601L, Sony explicitly addressed the friends of the simple receiver. In this respect, however, the double conversion set the quality bar high, the reception quality of the Sony was only rudimentarily copied by numerous similar devices with analog dials - from the Chinese ones to the last generation Grundig devices with internals from the Far East. The version ICF-7601 has 10 SW bands, the ICF-7601L has 9 SW bands + LW band (called European version). Instead of mechanical buttons used in ICF-7600AW, here are electronically switched buttons, there is still an OFF button to switch off the set.

General information:

  • Analog shortwave portable (dual conversion):1st IF: 10.700 MHz; 2nd IF: 455 kHz
  • Coverage: LW 145-285kHz (just on ICF-7601L), MW 530-1605kHz, FM 87.5 - 108MHz
  • SW are not continuous, are divided in 9 (ICF7601L)/10 (ICF-7601) bands:
    • LW/SW1: -/2200 - 4200 kHz, 120 m
    • SW1/SW2: 4600 - 5200 kHz, 60m
    • SW2/SW3: 5080 - 6400 kHz, 49 m
    • SW3/SW4: 6900 - 7500 kHz, 41 m
    • SW4/SW5: 9400 - 1000 kHz, 31 m
    • SW5/SW6: 11550 - 12150 kHz, 25 m
    • SW6/SW7: 13450 - 15450 kHz, 21 m
    • SW7/SW8: 15000 - 15650 kHz, 19 m
    • SW8/SW9: 17500 - 18150 kHz, 16 m
    • SW9/SW10: 21350 - 21950 kHz, 13 m
  • No memory preset possibility
  • FM filters: 3x 280 kHz (super wide, but can be changed to 180/150 kHz low loss type)
  • FM/AM front end+IF discri&amp+power amp. CX-20091, electronic switch for band selection uPD65005C-198
  • Output impedance and power: 8 ohm 350 mW max @ 10% distortion
  • Dimensions/weight: 192.5 x 122 x 35 mm, 570 g (incl. batteries)
  • Power: four AA batteries or external 6V (minus is the center pin!)
  • Produced: 1988 ... 1993 by Sony in Japan
  • Highlighted in the service manual: channels 5903kHz, 6207kHz, 11503kHz, 11958kHz, and 21870kHz may be difficult to receive due to internal spurious signals generated by the built-in oscillators.

Good things:

  • The noise level on MW and SW is very low
  • Very good selectivity and sensitivity on all bands
  • The dual conversion design does result in a smaller number of unwanted ghost signals that you find on single conversion sets in this price range, but is not as good as in as started from ICF-SW7600
  • very low power consumption (more than 30 hrs on FM and more than 26 hrs on SW with conventional AA batteries).
  • HOLD switch - deactivates all 5 push buttons: FM, MW, SW1/LW, SW2-10/SW1-9 and Power Off

Problems:

  • No light to illuminate the scale
  • No external antenna connection possibility
  • No provision for single-side band
  • No signal level indicator
  • The headphone jack is just mono, with a stereo jack you can hear just in the left speaker.
  • The band selector electrical switch is also the headache of this model: the uPD650005C (programmed CMOS gate array) is very sensible for ESD, and often became damaged. No replacement can be found.
Remark: "The biggest weakness of this rig is the intermodulation behavior of the second mixer - and this in spite of the FET already being quite heavily source degenerated at 33 kOhms. The problem basically is that the rx is constructed like a gain-limited low-voltage design and has too much gain (especially) in the RF amp and (not so much) the 1st mixer in combination with a wideband 1st IF, plus I guess the 2SK209-Y in the second mixer just isn't that great in terms of linearity." by Stephan Großklaß. Solution: Experiment with the value of pull-down resistor R15 (47k) to ensure that switching diodes D6, D7 are doing their job properly or decreasing the value of R30 (presently 3k9) to allow a higher V_CE and thus output voltage swing.


Sony ICF-SW7600

Sony ICF-SW7600

General information:

  • Digital shortwave portable (dual conversion): 1st IF: 55.8425 MHz (SW: 55.845 / 55.840 MHz, LW: 55.845 / 55.842 MHz); 2nd IF: 455 kHz
  • Coverage: AM 150kHz - 30MHz, FM 76.0MHz - 108.0MHz (stereo with headphones)
  • 5 kHz steps on all SW; LW: 3 kHz, MW: 9/10 kHz (selectable), FM: 100 kHz (depending by destination countries!)
  • 10 presets
  • SSB reception capability (LSB and USB)
  • Fine tuning for AM and SSB (officially +/- 5kHz, Radio Netherlands measured +/- 7 kHz) - but is not followed by frequency meter!
  • External antenna jack
  • Rec out jack (mono, mic level), plus remote jack for tape recorder switching (I never tested or use it)
  • Alarm and sleep functions
  • Frequency synthesizer / microcontroller: µPD1715G
  • Output: 400 mW max @ 10% distortion
  • Dimensions/weight: 191 x 118 x 32 mm, 615 g (incl. batteries)
  • Produced: 1990 ... 1993

Good things:

  • Low noise, good sensitivity (comparable to SW7600G, even a bit better on the low SW bands)
  • Good selectivity
  • Good frequency stability (no LO pulling) even on the high bands

Problems:

  • 5 kHz steps on SW are a bit coarse, especially for tuning SSB stations
  • Modest FM strong-signal handling and sensitivity (in case of SW7600G or SW7600GR is much better)
  • 10 presets for both AM and FM part together is very weak

Defects:

  • Typical of this model - dead electrolytics regarding poor SMT technology at that time

How I recognized which capacitors must be changed?

  • Lamp’s on/lighting time was very short
  • Audio part: FM stations sounds like AM part, almost no quality difference,
  • Often knocks at beginning of FM receiving, but after also sometime during listening.

What kind of capacitors I used?

  • For audio output and power: 470uF/10V and 1000uF/6.3V  Sanyo through hole electrolytics. All other electrolytics, like 4.7uF, 10uF, 22uF and 47uF I use tantalum, excepting audio part,
  • All audio amplifier parts (47uF/10V and 100uF/6.3V) I used Panasonic SMD electrolytics.
  • On power lines, I used tantalum capacitors
The result is quite exciting. Now really can enjoy stereo FM (with headphone).
Tantalum has its own advantage: because mostly are used for filtering (power supply or bypass), are better than electrolytics in this position.

Difficulties, what I meet:

  • In case of some electrolytics the electrolyte comes out. Does not damage the PCB pattern, but the surface of soldering are oxidized. That means is difficult to take out those capacitors – you should have a very good soldering skill (and station) to melt this composite.
  • The electrolyte goes under PCB pattern protection film, which should be removed with a glass fiber brush from damaged areas and covered the Cu pattern with solder.


Sony ICF-SW30(L)

Sony ICF-SW30

Is a portable short wave receiver for budget end of market. Sony says the ICF-SW30 is the smaller brother of ICF-SW33...in fact though it is much better value. Was the grandfather of ICF-SW55.

General information:

  • Manufactured between 1993-1996 by Sony in Japan
  • Alarm and sleep functions
  • Digital shortwave portable (dual conversion):1st IF: 10.700 MHz; 2nd IF: 500 kHz (use a 10.2 MHz quartz oscillator for conversion).
  • Coverage: AM 153-280kHz (marked as SW30L, was made just for UK and France market, but is difficult to modify the radio for LW reception), MW 531-1710kHz, FM 87.5 - 108MHz (stereo just with headphones). FM can be set to start from 76MHz via internal jumper.
  • SW are not continuous, are divided in 10 bands: 3700- 4200kHz, 4650-5150kHz, 5800-6300kHz, 6950- 7450kHz, 9375-10000kHz, 11525-12150kHz, 13375 -14000kHz, 14975-15600kHz, 17475-18100kHz, 21320-21950kHz
  • Adjusting steps: 1 kHz steps on SW, MW: 9/10 kHz, FM: 50 kHz steps
  • Synchronous detection
  • 15 presets (5 MW / 5 SW/ 5 FM) + 2 timer memories
  • AM bandwidth: nominal 5 kHz,
  • FM filters: 1x 280 kHz (super wide, but can be changed to 180/150 kHz low loss type)
  • Frequency synthesizer / microcontroller: µPD1724G
  • FM/AM front end+IF discri&amp CX20111, MPX LA3335M, power amp CXA1522M, 2V reg LA5002M, 3V reg S-81230AG, uOC393G battery detect
  • Output: 260 mW max @ 10% distortion - comes from a 8ohm, 0.3W with 66mm diameter speaker
  • Dimensions/weight: 169 x 112 x 35 mm, 448 g (incl. batteries)
  • Power: via 3 pcs of AA batteries or external wall plug/AC adapter, part of the pocket
  • Consumption: 25mA on MW, 30mA on FM and 50mA on SW

Good things:

  • The noise level of SW-30 is remarcably low
  • The dual conversion design does result in a smaller number of unwanted ghost signals that you find on single conversion sets in this price range.
  • Has Local/DX, tone and lock switches

Problems:

  • No light to illuminate the liquid crystal display in dark
  • No keypad for direct frequency entry
  • automatic scanning uses 1kHz on SW; 9 or 10kHz on LW and MW; and 50kHz steps on FM, but that only runs upwards, not downwards
  • no external antenna connection possibility
  • no provision for single-side band
  • a bit less sensibility compared with ICF-SW7600 family, including on FM
  • 15 presets, just 5 for FM or SW is very weak.
  • to jump from one end of the dial to another may take a bit of getting used to.
    • Recommendation: I changed the CF1 10.7Mhz (Murata type with 280kHz BW and 6-7dB loss) ceramic filter with a TDK 10.7MS type (3-4dB loss, 150kHz BW), and the sensitivity lightly increased on FM, and no any adjacent programs can be heard.
      Regarding small size, I recommend to change the normal electrolyte capacitors with solid electrolytic capacitors.
      Original price was 199 DM.


Sony ICF-SW7600G

Sony ICF-SW7600G

General information:

  • Digital shortwave portable (dual conversion):1st IF: 55.845 MHz; 2nd IF: 455 kHz
  • Coverage: AM 150kHz - 30MHz, FM 76MHz - 108MHz (stereo with headphones)
  • 1 kHz steps on LW/MW/SW plus a frequency grid: LW: 9 kHz, MW: 9/10 kHz, SW: 5 kHz; FM: 50 kHz steps
  • Synchronous detection
  • SSB reception (LSB and USB)
  • Fine tuning for SSB only (officially +/- 1.5 kHz, rather +/- 2kHz) - but is not followed by frequency meter
  • 20 presets (10 AM / 10 FM) + 2 timer memories
  • External antenna jack
  • Rec out jack (stereo, line level - I never used them)
  • Alarm and sleep functions
  • AM bandwidth: nominal 4 kHz, real more like 7 kHz (filter data: see the section about the filters below)
  • FM filters: 2x 280 kHz (super wide, but can be changed to 150/110 kHz low loss types)
  • Frequency synthesizer / microcontroller: µPD1724G
  • Output: 400 mW max @ 10% distortion
  • Dimensions/weight: 191 x 118 x 32 mm, 615 g (incl. batteries)
  • Produced: 1994 ... 2000

Good things:

  • 4 tuning keys is good (2 for fine, 2 for corse), and entering and recalling frequencies is pretty simple
  • Good selectivity.
  • Low LO phase noise, up to 27 dB on modified sets.
  • Best-in-class SSB reception - as opposed to most other compact portables, its product detector is sideband selective. Other-sideband AGC pulling still is annoying but one cannot expect true SSB filters in this league.

Problems:

  • Muffled AM audio - this is somewhat better with sync on, but weaker stations where that doesn't work too well. Its predecessors ICF-SW7600 sounds better. The SW7600G's tone switch only allows selecting between muffled and more muffled, which is hardly helpful -> see below how to improve it
  • The sync detector generates noise of its own and fails to lock on very weak signals. Normally sync detectors help with weak stations with fading, but in this case only the sideband separation can be used. If there is a weak station with interference, SSB should be used, which is much easier to do than with the older models.
  • On batteries, sensitivity straight off the whip isn't too exciting due to lack of an RF ground. Connecting a power supply, RF ground or using an external antenna helps.
  • The power supply jack is prone to connection problems and its polarity are inverted in comparison with SW7600 model -> you cannot use same power supply. In case of both models is soldered directly onto the circuit board, which means mechanical stress may damage the solder joints or even the PCB. If such a connection problem occurs, the jack needs to be re-soldered.
  • 20 (10+10) presets for both AM and FM part are still very weak.
  • Stereo output is only possible with headphones plugged in, even if using the rec out jack.
  • Weak bass reproduction even on headphones due to overly small coupling capacitors - this contributes to the overly mid-centric AM audio also on FM band.

In this radio I corrected/modified just 4 things:

  • The light diminishes within 15 seconds -> changed capacitor C206 47uF/6.3V with 150uF/4V TA ultra slim SMD type. Now the light dims approx 50 seconds.
  • In DC-DC converter the electrolytic capacitor (C605 22uF/16V) was changed into TA type (more suitable for several kHz frequencies)  22uF/20V TA.
  • Audio amplifiers output capacitors C512 220uF/6.3V connected to speaker/left channel phone and C514 47uF/16V connected to right phone channel both changed into 330uF/6.3V Panasonic type. Now the sound is more pleasant, also in both headphone speakers.
  • Tone mode switch circuit modification:
Sony SW7600G tone circuit
Originally the S4-1 tone switch in Music mode disconnect the C456 capacitor, the signal goes through C450 in series with C449 (the equivalent capacitor is approx 66nF). In News mode with S4-1 grounds the signal via C456, cutting the high frequency of audio. That method made the poor quality of sound also in FM mode, especially at low frequencies.
Modification: the unconnected pin of S4-1 with a wire are connected to out of C449, shortening it in Music mode, the signal goes just through C450 - coupling the amplifier via 1uF instead of previous equivalent 66nF.
With this easy modification and with changed output capacitors the sound became more pleasant. Can be heard the difference when you select on the Tone switch the News or Music on FM, and sounds like the old predecessor, the SW7600.


Sony ICF-SW11

It is a complete analog receiver, with a modern look, but "feels" cheap. Apparently, you did not expect too much from this, and later you will be surprised, especially if you mode it a bit.

General information:

  • Manufactured: Sony since 1999. My version was made in Japan, but now is produced in China
  • Analog 12 band (LW-MW-SW-FM) superheterodyne, stereo via jack / not selectable
  • No memory presets
  • Coverage: LW 141kHz - 290kHz, MW 525kHz - 1.620MHz, FM 87.5MHz - 108.0MHz (stereo with headphones), and 9 SW bands:
    • SW1: 4750 - 5060 kHz, 60 m
    • SW2: 5900 - 6200 kHz, 49 m
    • SW3: 7100 - 7350 kHz, 41 m
    • SW4: 9400 - 9900 kHz, 31 m
    • SW5: 11600 - 12100 kHz, 25 m
    • SW6: 13570 - 13870 kHz, 21 m
    • SW7: 15100 - 15800 kHz, 19 m
    • SW8: 17480 - 17900 kHz, 16 m
    • SW9: 21450 - 21750 kHz, 13 m
  • Intermediate frequencies: 450kHz for AM (single convertion), 10.7MHz for FM
  • Used ICs: AM/FM tuner circuit with stereo decoder: CXA1238M and amplifier: CXA1522M
  • Signal/noise ratio: no info
  • Sensitivity: no info
  • Output power: 0,14 W in speaker (4 ohms/57 mm) or 2x5mW in headphones, THD max 10%
  • Power: DC in 3V (700 mA), or 2 AA (R6) batteries. Current consumption (max): FM 22.2 mA; MW: 79.0 mA; LW: 79.0 mA; SW: 14.6 mA
  • Dimensions: 162 x 93.8 x 34.8mm, 0.34 kg including batteries

Good things:

  • In general high sensibility, including also the LW
  • Low power consumption, especially on FM and SW
  • Has a flip-stand on the backside, and the battery door is connected to the chassis against loss
  • The mechanism for indicating the selected band, moving the scale and gears to rotate the variable capacitor is top of the class.

Problems:

  • No stereo indicator, no mono/stereo switch
  • No tone control
  • The physical dimensions are too big to be used in any pockets.
Generally is a good radio. Internally is very similar to Panasonic RF-B11 (which sounds better regarding the higher diameter of speaker, has 2 FM IF ceramic filters in serial connection, and has stereo indicator, mono/stereo and tone switches) and Philips AE3405.
Modifications:
First time I used solid capacitors on power audio output (generally are designed for power line filtering), and the result is good: C61 100uF/6.3V and C66 470uF/6.3V both replaced with 470uF/6.3V OSCON. In this radio C60 470uF/6.3V was replaced with 470uF/6.3V OSCON, and the C52 100uF/6.3V filtering capacitor of RF IC1 was also replaced with 270uF/16V OSCON. All the rest of the electrolytics were replaced with the same value TA types. The ripple rejection capacitor C45 instead of 10uF/16V was replaced with 22uF/25V TA (in Philips AE3405 are used 47uF). R16 instead of 15k mentioned in service manual, have 150kohms value, and between pin 25 and 28 of CXA1238 (IC1) was inserted a 220kohms resistor - improving the AGC and the muting (like in Panasonic RF-B11). The used FM IF ceramic filter (230kHz type) was replaced with Murata 150kHz low loss type (SFE10.7JA Murata). The R29 10 ohms resistor was changed to 39uH/2.5ohms coil in power line of IC1.
With above mentioned modifications, via headphone, you will get a small monster, detailed audio band on FM with reach bass and smooth trebles.
If you needs a stereo indicator, easily can be made: connect one resistor of 2.2kohms to pin 4 of CXA1238, and on other end connect the cathode of a red LED, and the anode to the power supply (B+ 3V).


Sony ICF-SW7600GR

Sony ICF-SW7600G

Is the last and newest radio from Sony ICF SW7600 family - the best shortwave pocket radio made by Sony.

General information:

  • Digital shortwave portable (dual conversion):1st IF: 55.845 MHz; 2nd IF: 455 kHz
  • Coverage: AM 150kHz - 30MHz, FM 76MHz - 108MHz (stereo with headphones)
  • 1 kHz steps on LW/MW/SW plus a frequency grid: LW: 9 kHz, MW: 9/10 kHz, SW: 5 kHz; FM: 50 kHz steps
  • Synchronous detection
  • SSB reception (LSB and USB)
  • Fine tuning for SSB only (officially +/- 1.5 kHz, rather +/- 2kHz - but is not followed by frequency meter
  • has 100 presets divided in 10 pages, and can be mixed AM and 10 FM station in page + 2 timer memories
  • External antenna jack
  • line out jack (stereo, line level - I never used them)
  • Alarm and sleep functions
  • AM bandwidth: nominal 4 kHz, real more like 7 kHz (filter data: see the section about the filters below)
  • FM filters: 2x 280 kHz (super wide, but can be changed to 150/110 kHz low loss types)
  • Frequency synthesizer / microcontroller: µPD170734G
  • Output: 380 mW max @ 10% distortion
  • Dimensions/weight: 190 x 119 x 35 mm, 608 g (incl. batteries)
  • Produced: 2001 ... 2018

Good things:

  • 4 tuning keys is good, and entering and recalling frequencies is pretty simple
  • Good selectivity.
  • 100 memory location devided in 10 pages.
  • Best-in-class SSB reception - as opposed to most other compact portables, its product detector is sideband selective. Other-sideband AGC pulling still is annoying but one cannot expect true SSB filters in this league.

Problems:

  • Shortwave sensitivity seems to be better above 15 MHz than on the lower bands..
  • The built in telescopic antenna is very fragile and great precaution should be taken in extending it.
  • No RDS
I also refurbished my one, changing almost all 1uF, 10uF, and 47uF capacitors. To my surprise, most of them have lower rated voltage than in service manual (ex. instead of 10uF/50V was full with 10uF/16V) and the used brands I never meet before (R in a square and followed by a P and E). Their internal resistance and loss were too high. All was changed with Ta in power filtering parts, and Panasonic/Nichicon on audio. The headphone output capacitor 47uF was changed into 100uF. Now the sound is better, and the radio sounds like a new one. Also, the display green LED was changed with a very bright orange one.



Technics


Technics is a Japanese brand name of the Panasonic Corporation for audio equipment. Since 1965 under the brand name, Panasonic has produced a variety of hi-fi products, such as turntables, amplifiers, receivers, tape decks, CD players and speakers for sale in various countries. It was conceived for a line of high-end audio equipment to compete against brands such as Nakamichi.


Technics SA-5370

Technics SA-5370

Was the top model of mid-range SA-5170, SA-5270, and SA-5370 released in 1977 (the top model series are SA-5760, SA-5770, which have a higher output power (165W/channel on 8 ohm), and better sensibility (1.8uV instead of 1.9uV) and distortion (0.1% instead of 0.15%)).

General information:

  • Manufactured at 1977 by Technics, Division of Matsushita Electric Japan
  • 2 band analog superheterodyne receiver, MW and FM
  • Coverage: MW 525kHz - 1.605MHz, FM 88.0MHz - 108.0MHz
  • Antenna input impedance for FM: 300 ohms balanced and 75 ohms unbalanced,
  • No preset memory for FM
  • Usable sensitivity: 1.9 uV on FM mono and 20 uV for stereo; 30uV, 300uV/m on AM
  • Intermediate frequencies: 450kHz for AM, and 10.7MHz for FM
  • Used ICs: FM IF amplifier and AM circuit AN217; FM IF amplifier and detector: AN377; PLL type FM multiplex: AN363A; RIAA amplifier SVITA7129P (2 pcs)
  • Signal to noise ratio: mono 75dB, stereo 70dB for FM
  • Harmonic distortion: mono 0.15%, stereo 0.3% for FM
  • Output frequency range on FM: 20Hz - 15kHz (+0.5...-1.5dB)
  • Amplifier THD: 0.1% at rated power
  • Power bandwidth: 7Hz - 50kHz, -3dB
  • Output power: 2x56W/4 ohm or 2x48W/8 ohm continuous
  • Damping factor: 50
  • Input sensitivity: 2.5mV/47kohm Phono; 150mV/33kohm AUX; Tape 150mV/33 and 39kohm
  • Phono max input voltage: 150mV
  • Phono frequency response: +-0.2dB from standard RIAA curve
  • Tone controls: Bass 50Hz +-10dB; Treble 10kHz +-10dB
  • Loudness control (at -30dB volume) +10dB at 50Hz
  • Low filter (rumble): 100Hz -6dB/oct
  • High filter: 7kHz -6dB/oct
  • Output voltage at Tape Rec Out: 150mV
  • Channel separation and balance: 55dB, +-2.0dB
  • Headphone level and output impedance: 450mV/330 ohm
  • Power: ~220V/50Hz, consumption 450W
  • Dimensions: 450x142x330mm, 10.5 kg.

Good things:

  • Very nice backlight of scale
  • The amplifier has very warm and balanced sound, which is kept also during radio listening
  • Good sensitivity and selectivity on FM
  • Nice instruments - for signal and tuning

Problematic things:

  • The volume knob cannot be identified easily, all knobs has same diameter (bass, treble, balance, input selector), excepting the tuning knob, and is positioned almost in middle of front panel.
  • Difficult to repair (during changing all electrolytic capacitors).
With more than 40 years, is the best sounding receiver that I have. Was necessary to change all electrolytic capacitors.
Its sensibility outperforms some tuner with better specifications.
In some forums are mentioned, its sound is better than Marantz's 2220 and Technics SA-300 & SA-400. Both Technics receivers has almost same schematic with SA-5370, and the tuner part are also same with ST-8080. It retailed for about $330 back in 1977, which in today's dollars is roughly $1100!


Technics SA-80

Technics SA-80

This receiver was the bottom model of the new series from 1978 of Technics, and is completely the same as schematic with Panasonic SA80 (which chassis and knobs are made from plastic), and very similar to one year older model, the Technics SA-5070. The Power On and the Stereo indicator are originally made with LEDs, not bulbs.

General information:

  • Manufactured in 1978 by Technics, Matsushita Electric Industrial Co. Ltd., in Japan
  • 2 band analog superheterodyne receiver, MW and FM
  • Coverage: MW 525kHz - 1.605MHz, FM 88.0MHz - 108.0MHz
  • Antenna input impedance for FM: 300 ohms balanced and 75 ohms unbalanced,
  • No preset memory for FM
  • Usable sensitivity: 2.0 uV on FM mono and 22 uV for stereo; 30uV, 300uV/m on AM
  • Intermediate frequencies: 450kHz for AM, and 10.7MHz for FM
  • Used ICs: FM IF amplifier and AM circuit AN217; FM IF amplifier and detector: AN377; PLL type FM multiplex: AN363A; RIAA amplifier SVITA7129P (2 pcs), power amplifier STK459
  • Signal to noise ratio: mono 70dB, stereo 65dB for FM
  • Harmonic distortion: mono 0.2%, stereo 0.35% for FM
  • Output frequency range on FM: 30Hz - 15kHz (+1...-2dB)
  • Amplifier THD: 0.3% at rated power
  • Power bandwidth: 10Hz - 25kHz, -3dB
  • Output power: 2x18W/4 ohm or 2x17W/8 ohm continuous
  • Damping factor: 32 at 8 ohms
  • Input sensitivity: 2.5mV/47kohm Phono; 150mV/33kohm AUX; Tape 150mV/33kohm
  • Phono max input voltage: 95mV
  • Phono frequency response: +-1dB from standard RIAA curve
  • Tone controls: Bass 50Hz +-10dB; Treble 10kHz +-10dB
  • Loudness control (at -30dB volume) +10dB at 50Hz
  • Output voltage at Tape Rec Out: 150mV
  • Signal to noise ratio: 78dB on MM input, 93dB on other inputs
  • Channel separation and balance: 50dB, +-2.0dB
  • Headphone level and output impedance: 450mV/330 ohm
  • Power: ~220V/50Hz, consumption 100W
  • Dimensions: 441x134x277mm, 5.4 kg.

Good things:

  • Beautiful face design, warm sound

Problematic things:

  • Low output power
  • Just one instrument on the front panel (just signal strength, no tunning indicator)
  • No speaker decoupling and protection circuit, just a fuse of 3A/channel
  • No backlight for radio-scale, just for the pointer
  • The power of radio are made via an R-Dz-L divider, which is not the best and efficient voltage regulation, filtered by capacitors.
Is a nice bookshelf speaker driver - delivering just 15W/8 ohms, which means is recommended to be used with high-efficiency speakers.
All used ceramic filter are with orange mark - means their frequency is 10.73MHz.
Modifications:
Power line: C302, C701, C702 to 470uF/35V; CC413, C704 to 1000uF/35V; C310 to 270uF/25V; C619 390uF/35V
Signal: C211 1uF/63V ERO PP; C315 and C316 0.47uF/50V Wima; C411 and C412 1uF/63V ERO PP
Missing from the schematic: the power amplifier power line is fuse protected via 2 pcs of 3.15A fuse; the power switch are with 2 circuits, and both switches have in parallel 1-1 0.01uF/500V pop-up noise canceling capacitor. The power-transformer input voltage is selectable: 110-127-220-240 Vac. The pull-up resistor from the basis of output buffer transistors (Q301 and Q302) are missing from schematics and from PCB - later was soldered on the backside of PCB 1-1 27kohm resistor. The C309 on the schematic is 3.3uF/50V, in the receiver was mounted 4.7uF/50V.


Technics ST-Z1

Technics ST-Z1

Is a fine tuner with good selectivity on FM, 1.8uV, but just with one instrument with 2 functions: tune indicator on FM, and signal level on AM.

General information:

  • Manufactured by Matsushita Electric Industrial Co., Ltd. in Japan between 1980-82
  • Analog 2 bands (MW-FM) supeheterodyne radio,
  • No memory presets
  • Coverage: MW 525kHz - 1.605MHz, FM 87.5MHz - 108.0MHz
  • Usable sensitivity: 30uV on MW and 1.8uV on FM mono and 25uV for FM stereo
  • Has only 3 ICs: AN278 as FM IF amplifier, AN7001 which makes all functions (IF system, MPX decoder, indicators driver), and one AN6136 pop-noise canceller.
  • Output frequency range: 20Hz - 15kHz (+1dB...-2.0dB)
  • Signal/noise ratio: FM mono 69dB, FM stereo 65dB
  • THD: on FM 0.15% for mono, and 0.3% for stereo
  • Stereo separation: 47dB
  • Channel balance: 1.5dB
  • Alternate Channel Selectivity (FM): 60dB
  • Line output impedance and level: 1.8 kohm/300mV
  • Antenna input impedance for FM: 75 ohms or 300 ohms
  • Power: 220V/50Hz, Consumption: 18W
  • Dimensions: 410x142x223mm, 3.3kg

Good things:

  • Has a very clean sound, low noise, good channel separation
  • Nice front design with backlight and one analog instrument for signal strength and right channel adjustment

Difficult, problematic items:

  • Impressive hight, but inside has plenty of room.
The heart of this tuner is an IC (AN7001ST) which has integrated all functions, like in case of WEGA JPS352 SE T (AN7000), but they are not pin compatible. This tuner additionally has 2 more ICs: one for FM IF signal amplification (AN278) and one for pop-noise canceling (AN6136). The FM IF frequesncy is 10.67MHz, which makes difficult to change the ceramic filters. Improved the power line with an RF filter. The IC AN278 has two stages, and just one was in use -> based of Technics ST-S1, I modified the circuit, connecting the second stage into circuit, increasing the amplification. Now is possible to connect one additional ceramic filter to improve channel selectivity, but must be paired with existing 2, with 10.67MHz center frequency (orange dot marking). IC power pin grounded with 22uF/15V MLCC capacitor, and the C305 received in parallel a 47pF/50V C0G MLCC (recommended by user manual of AN7000). The R413 6.8kohm is better to be changed with a 22kohm semiadjustable resistor to adjust perfectly the channel separation.
Other changes: R3 390 ohm, R4 33kohm, IC101 received 1kohm between pin4 and 6, and disconnected from R103 and CF102. R103 removed, and one 390 ohm resistor connected between pin 5 and 8 of IC101, and pin 8 to CF102. Pin 9 of IC101 connected to ground via 22nF MLCC COG. To the anode of D201 and ground was mounted 3.3uF/16V OSCON. R210 33kohm, C210 390uF/35V. R409/410 now are 560 ohms, R411/412 are 4.7kohm, C407/408 1uF/50V foil capacitors. IC103 pin 9 connected to ground via 0.1uF/100V, and pin 3 and 4 connected to ground via 10nF and 22nF. C502 560uF/35V, C503 470uF/35V, C504/505 820uF/25V. D501 and T501 B-C shorted with one-one 22nF. Audio power line received one puffer capacitor 390uF/35V.
After modification was necessary to increase R102 from 220 to 270, because local stations became distorted regarding 2nd amplification stage. Now is OK. Probably can be solved inserting one more ceramic filter after CF102, but must be identical with CF102 - but this depending from tuner to tuner, because I have an other set from this, and there does not caused any problem this modification.
This tuners is same as the Technics ST-2700 FM/AM Stereo Tuner and similar to the Panasonic ST-2700L FM/MW/LW Stereo Tuner. An other similar Technics tuner is the ST-S1, which has LED signal level indicator and channel tunning indicator with related circuits. Technics ST-Z1L FM/MW/LW Stereo Tuner is the version with LW receiption capability.


Technics ST-G5

Technics ST-G5

Is an older brother of ST-G3. Has a frequency shift on FM (+25kHz) to capture adjacent channels when 2 radio programs are very close. Has selection possibility between narrow and supper narrow (150kHz) FM IF filters, signal level indication in dB, and auto search mode.

General information:

  • Manufactured by Technics in Japan between at 1984-1986
  • Digital 2 bands (MW-FM) PLL radio,
  • 16 memory presets:8 for FM and 8 for AM
  • Coverage: MW 522kHz - 1.611MHz; FM 87.5MHz - 108.0MHz
  • Adjusting steps: MW 9/10kHz; FM 50/100kHz for EU/USA version (switchable on rear panel)
  • Usable sensitivity: 20uV on MW, 0.95uV on FM mono and 22uV for FM stereo
  • FM IF/AM IF amp IC: uPC1018C; FM IF det.: uPC1167C2; MPX decoder uPC1161C3; Prescaler: uPB563C-E; PLL controller uPD1704G533; Pilot cancel and DC amp: AN6552; FL display driver: AN6873
  • Output frequency range: 5Hz - 18kHz (+0.2dB...-0.5dB)
  • Signal/noise ratio: AM 55dB, FM 78dB mono, 71dB stereo
  • THD: on FM 0.03% for mono, and 0.04% for stereo
  • Stereo separation: 55dB
  • Line output level: 1000 mV
  • Antenna input impedance for FM: 75 ohms or 300 ohms
  • Power: 220V/50Hz, Consumption: 9W
  • Dimensions: 430x53x245mm, 2.4kg

Good things:

  • High quality of electrical parts used, especially in case of solid capacitors
  • Good selectivity and sensitivity on FM (0.95uV)
  • Very low distortion on FM (0.04% on stereo), good stereo separation (55dB) and high signal/noise ratio (78dB)

Difficult, problematic items:

  • The signal level indication cannot be seen together with received frequency, just separately on the same display
  • Very low profile, just 245mm deep.
Capacitors were in the wrong shape, especially the supercapacitors for memory: 2 pcs 3.3F/2.3V connected in series.


Technics ST-G3S

Technics ST-G3S

Is a quartz synthesizer LW-MW-SW-FM stereo tuner with DC linear switching MPX. Has a DCB circuit for 12-band SW reception, and signal level indication in dB. Based on the specification, was designed mostly for FM and SW DX-ing (high sensitivity), because the LW and MW sensibility is a bit less than average.

General information:

  • Manufactured by Technics in Japan between at 1985-1987
  • Digital 4 bands (LM-MW-SW-FM) PLL radio, with 12-bands on SW
  • 16 memory presets:8 for FM and 8 for AM
  • Coverage: LW 153kHz - 281kHz; MW 522kHz - 1.611MHz; SW 2.3MHz - 26.1MHz (see below), FM 87.5MHz - 108.0MHz
    • Shortwave bands:
    • SW1: 2300 - 2500 kHz, 120 m
    • SW2: 3200 - 3400 kHz, 90 m
    • SW3: 3900 - 4000 kHz, 75 m
    • SW4: 4750 - 5060 kHz, 60 m
    • SW5: 5950 - 6200 kHz, 49 m
    • SW6: 7100 - 7300 kHz, 41 m
    • SW7: 9500 - 9775 kHz, 31 m
    • SW8: 11700 - 11975 kHz, 25 m
    • SW9: 15100 - 15450 kHz, 19 m
    • SW10: 17700 - 17900 kHz, 16 m
    • SW11: 21450 - 21750 kHz, 13 m
    • SW12: 25600 - 26100 kHz, 11 m
  • Adjusting steps: LW and MW 9kHz; SW 5kHz and FM 50kHz
  • Usable sensitivity: 1000uV on LW, 500uV/m or 20uV on MW, 8uV on SW and 0.95uV on FM mono and 22uV for FM stereo
  • FM IF/AM IF amp IC: AN7274SN; FM IF amp: AN278; MPX decoder AN7472S-A; PLL controller uPD1714G511A
  • Output frequency range: 4Hz - 18kHz (+0.5dB...-1.5dB)
  • Signal/noise ratio: AM 45dB, FM 76dB mono, 71dB stereo
  • THD: on FM 0.09% for mono, and 0.2% for stereo
  • Stereo separation: 50dB
  • Line output level: 500 mV
  • Antenna input impedance for FM: 75 ohms or 300 ohms
  • Power: 220V/50Hz, Consumption: 9W
  • Dimensions: 430x53x245mm, 2.2kg

Good things:

  • High quality of electrical parts used, especially in case of solid capacitors
  • Good selectivity and sensitivity on FM (0.95uV) and SW (8uV)

Difficult, problematic items:

  • Station memories for both FM and AM are very low, especially if you use frequently the SW.
  • Very low profile, just 245mm deep.
  • Rare, I did not found any detailed info or service manual about this tuner with SW, just about the ST-G3, which is different.
Capacitors were in the wrong shape, especially the supercapacitors for memory: 2 pcs 3.3F/2.3V connected in series.


Technics ST-G450

Technics ST-G450

Is a quartz-synthesizer 2 band stereo tuner. Has Class AA output amplifier for best fidelity. The digital tuning uses an unwavering quartz crystal reference to prevent drift while promoting astounding accuracy and convenience. Use the traditional Technics DC construction which enhances waveform fidelity while extending flat frequency response down to 4Hz. Has a 24 channel random access preset memory and a large FL display.

General information:

  • Manufactured by Matsushita Electric Industrial Co. Ltd in Japan between 1988 to 1990
  • Digital 2 bands (MW-FM) PLL radio without RDS capability,
  • 24 random access memory presets, organized in 9+10+5
  • Coverage: MW 522kHz - 1.611MHz, FM 87.5MHz - 108.0MHz
  • Channel space: 9kHz for AM and 50kHz for FM
  • Intermediate frequency: 450kHz for AM and 10.7MHz for FM
  • Usable sensitivity: 20uV, 300uV/m on AM, 1.3uV on FM mono, and 21uV for FM stereo
  • Integrated circuits: FM IF IC: AN7274NS, stereo decoder: AN7472S, PLL freq. synthesizer: LM7001, electronic tuning controller and FL display driver: M50941-421SP; IF amplifier: AN278, audio output amplifier: AN6554F
  • Output frequency response on FM: 4Hz - 15kHz (+0.5...-1dB)
  • Signal/noise ratio: AM 50dB, FM 80dB mono, 72dB stereo
  • THD: on FM 0.05% for mono, 0.1% for stereo
  • Stereo separation: 50dB
  • Alternate channel selectivity: 65dB
  • Antenna input impedance for FM: unbalanced 75 ohms, for AM: loop antena connector and an external antenna connection possibility
  • Output signal level: 0.45V
  • Power: 220V/50-60Hz, consumption: 9W
  • Dimensions: 430x64x241mm, 2.2kg

Good things:

  • Has a very clean sound, low distortion, low noise
  • Big FL display

Difficult, problematic items:

  • No wide and narrow IF filters selection possibility for FM
  • Just average sensibility
  • No muting during searching. Exist auto searching mode (pushing longer the Up/Down tuning buttons, but is not so sensible
  • No fuse on primer circuit of transformer - recommended to be additionally inserted.
The schematic (as source was used one from G460 model, because the G450 I did not find on the net) is very similar to ST-G460/470/550/560/570/650, the main difference of G450 is the tuner section has just 3 gangs, uses just 2 ceramic 10.7MHz +-180kHz filters (SFE10.7MZ), no IF wide/narrow selection possibility, and less memory. The PCB contains all pads to be implemented the Wide/Narrow IF filtering selection possibility (like in GT550 or G6T). Considering the endless list of similar tuners, Technics made just minor modifications and release them as new models.

Modification (above changing all electrolytics):
Power line: C104 fron 10uF to 47uF/63V, C106 & C901 from 470uF/6.3V to 1000uF/35V, C114 & C303 from 100uF/35V to 390uF/35V, IC 302 received a 100uH coil follower by a 390uF/35V puffer capacitor. C705 from 1000uF/25V to 2200uF/25V, C706 from 2200uF/25V to 3300uF/35V, C707 from 220uF/16V to 470uF/35V, C710 from 10uF/16V to 100uF/63V, C915 from 1000uF/6.3V to 2200uF/25V. At AC power input before received an EMI filter circuit formed by 2.2nF/2kV ceramic capacitor, the original filter coil, and after in parallel with primer of transformer one 1uF/275Vac pp foil capacitor. On both secunder coils received 1-1 220nF/275Vac PP capacitors. Because during usage the Q701 temperature was high, I inserted a heatsink on it.
Modifications in other circuits: at IC901 CE (pin 3) received a 100pF to ground and on AM_IN (pin 10) input line 3.3uH at the input. R102 was changed from 1.5kohms to 560 ohms, and the R103 from 330 ohms was changed into 560 ohms (like at GT550 & GT650). The pin 18 of IC102 now is connected to the power line via 100pF ceramic (like at G570).
Audio output: in case of the audio signal can be seen mostly DC connection, no capacitors - excepting the output of class AA circuit. If we take a look at the value of the output capacitor, seems very low. The output works in the best case (not considering the input resistance of the power amplifier and the impedance of output MPX filter, for simplicity) on 5.6Kohms + 2.7kohms resistor via 3.3uF, which means cannot be achieved the advertised 4Hz, as lower end of the audio band, just with a high loss. I put in this position (C315 and C316) 10uF/100V pp foil instead of 3.3uF/50V electrolytics (3x higher value!). Now the sound is in its right place with detailed bass and treble.
The new class A or called Class AA is a small trick, the output transistors conduct all time, just like the case of real class A amplifiers, for this reason, they never switch off, switching distortion is eliminated - but in reality, they work in class B. This is achieved with a special biasing of transistors: as the audio waveform begins to swing from positive to negative or vice versa, a very high-speed diode acts to raise the bias current slightly, the transistor remains in a low-level conducting state until the signal swing back again.



Telefunken


Telefunken was a German radio and television apparatus company, founded in Berlin in 1903, as a joint venture of Siemens & Halske and the Allgemeine Elektricitäts-Gesellschaft (AEG). In 1941, Siemens transferred its Telefunken shares to AEG as part of the agreements known as the "Telefunken settlement". During the Second World War, Telefunken was a supplier of vacuum tubes, transmitters and radio relay systems, and developed Funkmess facilities (later referred to as radar devices by the US Navy) and directional finders, as part of the German air defence against aerial bombing. During the war, manufacturing plants were shifted to and developed in west of Germany or relocated. Thus, Telefunken, under AEG, turned into the smaller subsidiary, with the three divisions realigning and data processing technology, elements as well as broadcast, television and phono. In 1967, Telefunken was merged with AEG, which was then renamed to AEG-Telefunken. In August 2006, it was acquired by the Turkish company Profilo Telra, one of the largest European manufacturers of TV-devices, with brand-owner Telefunken Licenses GmbH granting a license for the Telefunken trademark rights and producing televisions under that name.


Telefunken 076WK

Telefunken 076WK

This radio also comes from family, and was used from 1941 at Erzsébetváros (Elisabethstadt/Appeschterf, Orastie, in Transylvania - now part of Romania) till the end of '70s.

General information:

  • Principle: superheterodyne, with IF=468kHz
  • Manufacturer: Telefunken Deutschland mbH
  • Bands: 3 - LW, MW and SW
  • Tubes: 6 pcs - ECH11, EBF11, EF11, EL11, EM11 and AZ11
  • Power supply: alternating current 110-240V, 50Hz
  • Speaker: moving coil with field excitation coil (no magnet)
  • Input: AM antenna and turntable
  • Dimension: 600x390x300 mm
Condition: working, but the band selector switch is not so stable.



Tivoli Audio


Tivoli Audio is an American manufacturing company notable for producing a line of up-market tabletop radios and related audio products. It was founded in 2000 by Tom DeVesto in collaboration with Henry Kloss, who perceived a gap in the consumer audio market for a high-quality, well designed and affordable AM/FM radio in congested urban locations, while maintaining the ability to pick out distant or low power stations.. Tivoli Audio is best known for its Model One Radio. By 2006, Tivoli Audio had become a global luxury brand, selling in over 30 countries and gaining recognition in the audio and design world.


Tivoli Audio Model One

Tivoli Audio Model One

This amazingly affordable (?) and musical table radio was designed by the famous designer, Henry Kloss. Tivoli doesn't publish any specs on the Model One, but the radio has at least decent selectivity, given the cleanness and lack of ambiguity with which it pounces on every station. I have the Cherry/Silver version with a compact, handmade natural cherry wood cabinet providing an acoustically inert housing. The design is classic, almost hearkening back to old valve radios. The front has three knobs: source, volume, and tuning. The tuning knob has a quality vernier drive, is geared down 5:1 with an amber light to let you know you've got it perfectly locked on. On the front symmetrical balance to the tuning knob is achieved with a 3-inch speaker, (heavy-magnet, long-throw). The audio section is well built with a powerful amplifier, a strong magnet for the loudspeaker, and a bass port design for the wooden cabinet. All are factors that contribute to its reputation for good audio. Has been equalized for enhanced bass and treble with the mid's some 6 dB down. These are well-known tricks for getting a warm and crisp sound with universal appeal.
Antennas are internal but a rear jack allows for an external FM aerial where required (an FM telescopic aerial is included). The antenna signal is captured by a discrete-component FM tuner with GaAs MES-FET mixer, which gives low noise, high sensitivity even with closely spaced stations.

General information:

  • Designed by Tivoli Audio, Cambridge, Massachusetts, USA, but the radio is Made in China between 2000 - 2008
  • Analog 2 bands (MW-FM) mono table radio (mono also in line out/headphone jacks)
  • No memory presets
  • Coverage: MW 522kHz - 1.611MHz, FM 87.5MHz - 108.0MHz
  • Usable sensitivity: no info
  • FM/AM tuner with IF section: TEA5710; audio input TL081; equalizer/tunning indicatot and voltage ref: TL084; headphone driver NE5532; power amplifier TDA7266
  • Output frequency range: no info
  • Signal/noise ratio: no info
  • THD: no info
  • Antenna input impedance for FM: 75 ohm
  • Driver: 3" (76.2 mm) fullrange, 8 ohms/5W driver
  • Power: 230V/50Hz, consumption: max 25W, or via wall plug 12Vdc/800mA (diode protected)
  • Dimensions: 213x114x133mm (WxHxD), 1.9kg

Good things:

  • Has a good readable tuning knob geared down 5:1
  • good sensibility and selectivity on both bands, AM and FM
  • Tuning indicator a well designed, easy to adjust to the highest signal level
  • Very robust design, well made

Difficult, problematic items:

  • One weakness that manifested itself after few years in this particular radio is that it became hard to tune, scratchy, and unstable on FM due to intermittent contacts in the tuning capacitor. Easily can be "repaired": aggressively rotate the tuning dial CW/CCW a few times, repeating this on the whole scale.
  • No possibility to get out the MPX signal for upgrade
Just for daily listening, in a kitchen or for the office, or just near your bed is the best choice to have a simple, good-sounding table radio. Are well built, but if you open it, you can see plenty outdated cheap components. For better performance, low value capacitors were selected with high voltage (100V) rating (ABAcon, some never heard Chinese capacitor maker), because they have better characteristics, then the low voltage ones. All were changed into foil capacitors, and now the sound is more clear, but the tonality/warmness remain. Also the used ICs were more than 15 years old from first release of this radio (2000).



WEGA

(Sony)


WEGA, was founded as Wuerttembergische Radio-Gesellschaft mbH in Stuttgart, Germany in the year 1923. Sony purchased WEGA in 1975, which means after aquisition several models were built under Sony design. Wega products were then known throughout Europe for stylish and high-quality stereo equipment, designed by Hartmut Esslinger, amongst others. Sony used the Wega name for different products (Trinitron flat screen or LCDs TV sets). Defunct at 2005.


WEGA JPS352 SE T

WEGA JPS352 SE T

General information:

  • Manufactured at 1979 by WEGA-Radio GmbH, Fellbach, (West) Germany
  • 2 band analog superheterodyne tuner, MW and FM
  • Coverage: MW 510kHz - 1.640MHz, FM 87.5MHz - 108.0MHz
  • Antenna input impedance for FM: just 75 ohms unbalanced,
  • No preset memory for FM
  • Usable sensitivity: 2.0 uV on FM mono (no any data for stereo or for AM)
  • Intermediate frequencies: 450kHz for AM, and 10.7MHz
  • Has only one IC, which makes all functions (IF system, MPX decoder, indicators driver): AN7000.
  • Signal to noise ratio: mono 72dB, stereo 64dB for FM, and 53dB for AM
  • Harmonic distortion: mono 0.2%, stereo 0.8% for FM, and 0.5% for AM
  • Output frequency range: 40Hz - 15kHz (-2...+2dB)
  • Power: ~220V/50Hz, consumption 15W
  • Output power: 750mV/2.2kohm
  • Dimensions: 430x100x230mm, 3.7 kg.
The surprise was the high level of integration: just the FM tuner, the output MPX filter, and audio amplifiers are built with discrete components, and all the rest of the functions are made just by one IC - and that was in 1979! Despite 2.0uV sensitivity, the reception is quite good, warm sound, like Technics SA-5370. Unfortunately, both meters were out of order, I changed them with real instruments.
Additionally received an AC filter. All electrolytic capacitors changed. IC power pin grounded with 1uF/35V X7R MLCC, also the C125 received in parallel a 47pF/50V C0G MLCC (recommended by user manual of AN7000), and in the audio output stage a puffer capacitor (22uF/63V).
In series with scale light bulbs received a 20ohm NTC resistor (to protect them, because the tuner was built for 220VAC, and now in my home, I can measure 238VAC).
The signal from FM antenna input socket goes into the L101 impedance adjusting transformer, which has an output for a 300-ohm antenna connection - can be used if somebody has such an antenna.
This radio on several portals are mentioned as a Sony clone.


WEGA T120

WEGA T120

General information:

  • Manufactured between 1980-82 by WEGA Elektronik GmbH, Köln, (West) Germany
  • 3 band analog superheterodyne tuner, MW and FM
  • Coverage: LW 150kHz - 344kHz, MW 522kHz - 1.602MHz, FM 87.5MHz - 108.0MHz
  • Antenna input impedance for FM: 75 ohms unbalanced and 300 ohms balanced. Haa an external antena input for AM, selectable from the backside via a switch
  • No preset memory for FM
  • Usable sensitivity: 1.3 uV on FM mono, 250uV/m with builtin antenna and 100uV/m with external antenna for MW, 500uV/m with builtin antenna and 250uV/m with external antenna for LW
  • Intermediate frequencies: 450kHz for AM, and 10.7MHz (green body, marked with white dot, inscription 10M)
  • Used ICs: FM mixer and osc: SC-114D; FM IF LA1231; MPX decoder uPC1161C; AM: LA1240; servo lock: uPC4558C; signal level: LB1416
  • Signal to noise ratio: mono 65dB, stereo 60dB for FM, and 50dB for AM
  • Harmonic distortion: mono 0.15%, stereo 0.4% for FM, and 0.5% for AM
  • Output frequency range: 40Hz - 15kHz (-2...+2dB)
  • Power: ~220V/50Hz, consumption 7W
  • Output power: 300mV/2.2kohm
  • Dimensions: 430x80x275mm, 3.6 kg.
Is completely similar to Sony's ST-A30L tuner (Wega was part of Sony). Has a very good sensibility - is just a 3 gang tuner on FM and 2 gangs on AM. In stereo mode is automatically activated the muting circuit. Has a High-Blend switch to decrease the sizzle noise in high frequency from the audio signal.
Differences compared to service manual: not mounted C602 and C603 from the AFC circuit (both 0.47uF), and the value of C204 instead of 1uF is 4.7uF/25V.
All electrolytic capacitors were changed. ICs buffer capacitors were replaced with 470uF/35V (C212, C301, and C422).
In power supply the C803 changed to 2200uF/25V, C805 to 470uF/35V, C804 and C808 to 390uF/35V, C806 to 100uF/63V.
In the audio part, I used just PP capacitors. Just the output capacitors value was changed/increased from 0.47uF to 1uF (C313 and C363), because the bass section does not need any changes. The set has a very warm sound reach in the bass section.
After the power switch, I mounted an EMI filter before power transformers primar coil (2.2nF+2x7.6mH+0.47uF), which was necessary to be shielded.
Overall, is a good tuner with high sensibility on FM, good "acute servo lock", and is very listenable! The AM section is not so good, the sound is not distorted, but the background noise is high.



XHData


Is very difficult to determine the name of original manufacturer, because can be seen as made by Radiwow, or by Sihuadon. All 3 brands appears under xhdata.com.cn webpage. Sihuandon D808 is exactly same as XHdata D808, just in black color with orange backlight. Raiwow R108 is completely same with Sihuadon R108. Is quite difficult to have a clear picture who is the real manufacturer of those sets.


XHDATA D808

XHDATA D808

Is my newest pocket radio with DSP. Appears on the market in 2018, made by Radiwow, a Chinese company. Has Squelch Control (works On all bands which is unusual), Fast/Slow/Stop (Lock) Tuning Speeds. The second display is switchable: Time (Default), Signal Strength/Signal To Noise ratio, Temp (Fahrenheit or Centigrade), and Alarm Time. Tune via Knob or Up/Down Buttons with ATS (Automatic Tuning System), and Direct Frequency Entry keys.

General information:

  • Digital 5 bands (LW-MW-SW-FM-Air) DSP radio with RDS and Radio Text capability,
  • 500 memory presets, 100 for each bands, all with 10-10 memory pages
  • Coverage: LW 150kHz - 450kHz, MW 522kHz - 1.620MHz/520kHz - 1710kHz, SW 1.711MHz - 29.999MHz, FM 64MHz - 108.0MHz (selectable bandwith), AIR 118MHz - 137MHz
  • Channel space: (10k)9kHz/1kHz for LW/MW; 5kHz/1kHz for SW, 100kHz/10kHz for FM and 25kHz/1kHz for AIR
  • Fine adjusting possibility for all AM bands
  • LSB/USB selection possibility on SW
  • Selectable digital audio bandwidth filters MW/SW: 1, 1.8, 2, 2.5, 3, 4, 6kHz, and for SSB: 0.5, 1, 1.2, 2.2, 3, 4kHz
  • Usable sensitivity: 10mV/m on LW, 0.5mV/m on MW, 10uV on SW, 3uV on FM, 0.5uV on AIR. Not specified the signal level for FM stereo reception
  • Integrated circuits: Silicon Labs Si4735 DSP Chip
  • Stereo just via headphone
  • Has external antenna input for SW-FM-AIR
  • Built in speaker: 8 ohm/1W
  • Power: from a 3.7V Li-ion accumulator 18650/2000mAh, chargeable via a micro USB jack, 5V (<10hrs charging time)
  • Dimensions: 157x92x32mm
  • Weight: 265g without battery
  • The box contains: the radio + user manual + specific bag + external antena wire + USB charge cable + 18650 Li accumulator (2000mAh)
Good things:
  • The display light can be switched permanently on and has also a temporization when is off but you press any buttons, for 30 sec
  • Has signal level indicator, temperature meter, time, alarm, snooze functions, etc
  • Selectable digital audio filters for AM, which is good especially on SW to cancel channel noise
  • Selectivity and sensitivity is quite good on FM and is remarkable on MW (better than Sony ICF SW7600GR or Sangean ATS-909X)
  • With one charge of Li-ion 18650/2000mAh accumulator, the radio can be used 30-34 hrs. In StandBy consume is high <90uA!
  • USB charging possibility
  • Very easy station storage: depressing a number button on the keypad for more than 3s stores a frequency
  • The Signal Metering helps with comparative numerical readouts of both signal strength and signal to noise ratio.
  • ATS (Auto Tuning System) can be activated on any bands, just holding for more than 2 sec the band button.
  • External Antenna Jack also works on FM but does not disconnect the whip antenna.
  • Adjacent stations' rejection is very good. Example on FM at +-100kHz is -5-7dB, at +-150kHz is -30dB, at +-200kHz drops below -45dB!
Difficult, problematic items:
  • Special function marks above button can be seen just in a bright environment (dark orange marks on a grey background)
  • Cannot be switched off the auto muting function during searching
  • ATS has a disadvantage: will store just the stations with good signal, and that threshold limit cannot be adjusted
  • Keyboard buttons are too flat, difficult to identify them in dark, and no button-lights
  • Does not remember the second numeric display setting, always after switch on you must set again for example to signal meter
  • The sound via speaker is sharp, via headphone is enjoyable
  • RDS/RT sensitivity is low and slow, takes time till the info will appear on displayis and presented the whole content
  • At first time switch on was like an auto-configuration: poor reception quality, insensible, but after 30 minutes operation all goes to normal level (and this is not just my opinion, also are mentioned on a few blogs/forums).
Seems "inspired" (to use a generous term) by the introduction of C. Crane's breakthrough Skywave SSB model in 2017 at the same Shenzhen city, China location a few months earlier. The Chinese startup company essentially had the chance to benefit from C. Crane's substantial R&D costs, copy all of the Skywave SSB's strong points and improve upon its weak points-including the $169.99 price. The end result is a very competitive DXing radio with a current reputation for high quality. In many parts of the world this radio has become the premier portable radio for DXing purposes.
From a DSP do not expect a miracle in sound quality, but this is a quite good, cheap, and sensible pocket radio for daily listening. In conclusion this radio is very similar to C. Crane Skywave SSB (as presented before) and Digitech AR-1780.

Recommendation: The radio has a quite big speaker (in diameter is approx 7cm), almost the maximum which can be mounted into its plastic chassis but sounds like a cheap pocket receiver. The reason is the low value of the output capacitors. If we consider the speaker as an 8ohm resistor, with 100uF capacitor the cutoff frequency is approx 200Hz. The used capacitor was a very cheap model with poor parameters (high dissipation factor and high ESR). I changed both of them with a 470uF/6.3V Nichicon Fine Arts type, and now the cutoff frequency became 42Hz. Now the music on FM via speaker is much better, and via headphones became alive! The second modification was to decrease the output noise which can be heard at minimum volume via headphone. For that I inserted one 6.8nF C0G MLCC capacitor connecting both outputs of audio amplifier. This method are used in old FM receivers, called "high-blend" filter, and eliminate the noise with same phase from signal. Try both modifications, and you will be surprised by this improvement in sound quality.
The original Li-ion accumulator can be replaced with a higher capacity one. Now I use a 5000mAh type, and the listening time is doubled, and charging time increased, but does not cause any problem.
Remark: when you purchase as a new one, the radio can be powered on just if you put it on a charger.
Squelch capability: is not mentioned in the User manual, but can be activated by long pressing the Tuning knob, and waiting for the "Squelch" readout to show up at the bottom of the display. While still pressing in the Tuning knob you can adjust the Squelch level by turning the Tuning knob clockwise to raise the squelch level from 1 to 9. Although this Squelch function is available on all bands on the D-808, but it is apparently useful only on the AIR band.
Related links:
       Georges' review of the XHDATA D-808, is a good revies on The SWing Post abou his experience withthis radio.
       Reviews For: XHDATA D-808 Portable, is a revies on EHAM radio.
       XHDATA D-808 AM/FM/SW/SSB/Airband Portable Radio, is a revies on RadioJayallen, the most detailed what I found.
       A detailed review of the XHDATA D-808 and comparison with the Tecsun PL-660, is a revies made by 13dka with several replies.



Yamaha


Nippon Gakki Co. Ltd. (currently Yamaha Corporation) was established in 1887 as a reed organ manufacturer by Torakusu Yamaha in Hamamatsu, Shizuoka Prefecture and was incorporated on October 12, 1897. In 1900 the company started the production of pianos. The first piano to be made in Japan was an upright built in 1900 by Torakusu Yamaha, founder of Nippon Gakki Co., Ltd. - later renamed Yamaha Corporation. The company's origins as a musical instrument manufacturer are still reflected today in the group's logo-a trio of interlocking tuning forks.
Yamaha has grown to become a leading manufacturer of semiconductors, audio/visual, computer related products, sporting goods, home appliances, specialty metals and industrial robots.


Yamaha R-3

Yamaha R3

Is a receiver amplifier with a very natural sound from 1985-86.

General information:

  • Digital 2 bands (MW-FM) PLL radio without RDS capability,
  • 16 memory presets, 8 for FM and 8 for AM
  • Coverage: MW 520kHz - 1.610MHz, FM 87.5MHz - 108.0MHz
  • Channel space: 9kHz for AM and 50kHz for FM
  • Intermediate frequency: 450kHz for AM and 10.7MHz for FM
  • Usable sensitivity: 250uV on AM, 1.55uV on FM mono and 21uV for FM stereo
  • Integrated circuits: FM IF IC: LA1235, stereo decoder: LA3400, PLL freq. synthesizer: LC7000, electronic tuning controller: LC7030; display driver LB1214; BA618 LED signal level indicator; M5220L OPA for RIAA
  • Output frequency response on FM: 30Hz - 15kHz (-1...+1dB)
  • Signal/noise ratio: AM 50dB, FM 81dB mono, 76dB stereo
  • THD: on FM 0.1% for mono, 0.20% for stereo
  • Stereo separation: 40dB
  • Antenna input impedance for FM: 75 and 300 ohm
  • Amplifier part: continuous power on 8 ohm: 35 W / channel, THD 0.01% (10...40000 Hz)
  • Amplifier input sensitivity: PHONO (MM) 2.5mV / 47 kohm; CD, VIDEO and TAPE 150mV / 4.7 kohm;
  • Amplifier tone control: Bass 50Hz ±10dB, Treble 20kHz ±10dB, Bass extension *8dB 60Hz
  • Amplifier signal to noise ratio (A weightened) 88dB for PHONO, 103dB for other inputs
  • Power: 220V/50-60Hz, consumption: 180W
  • Dimensions: 436x126x289mm, 5.2kg

Good things:

  • Has a very clean sound, beautiful bass, low noise
  • Has signal level indicator

Difficult, problematic items:

  • 2x8 preset memories are not enough, especially for FM
Considering its age, was necessary to change almost all electrolyte capacitors.




FM stations received at my home (Budapest, 2nd district, close to Danube river), signal strenghts measured with XH Data D808 radio with its telescopic antena (without any external one, inside my home):

88.1 MHz

Info Radio - news

31 dB/u

88.8 MHz

Maria Radio - religious

40 dB/u

89.5 MHz

Radio1 - Pop music

60 dB/u

90.3 MHz

Tilos

49 dB/u

90.7 MHz

Bartok - classical music

17 dB/u

90.9 MHz

Jazzy - Jazz music

31 dB/u

91.7 MHz

Maria Radio - religious

15 dB/u

92.1 MHz

Klasszik - classical music

52 dB/u

92.9 MHz

Spirit - general

34 dB/u

94.2 MHz

Trend FM - general

45 dB/u

94.8 MHz

Petofi - general

46 dB/u

95.3 MHz

Karc FM - general

43 dB/u

95.5 MHz

Kossuth - general

21 dB/u

95.8 MHz

Slager - general

51 dB/u

96.9 MHz

Regina, Slovakian - general

5 dB/u

97.3 MHz

Maria - religious

25 dB/u

98.6 MHz

Manna FM - general

47 dB/u

99.5 MHz

Best FM - general

55 dB/u

99.8 MHz

Danko - popular music

8 dB/u

99.9 MHz

Best FM - general

13 dB/u

100.8 MHz

Danko - popular music

52 dB/u

101.6 MHz

Sola - religious

34 dB/u

102.1 MHz

Katolikus Radio - religious + classical music

48 dB/u

102.7 MHz

Petofi - general

25 dB/u

103.3 MHz

Retro Radio - retro music ('60, '70 and '80)

57 dB/u

104.3 MHz

Slovakian radio

6 dB/u

104.7 MHz

Retro Radio - retro music ('60, '70 and '80)

21 dB/u

105.3 MHz

Bartok - classical music

53 dB/u

105.6 MHz

Bartok - classical music

16 dB/u

107.2 MHz

Kossuth - general

11 dB/u

107.8 MHz

Kossuth - general

49 dB/u


Stations list was updated at 14.06.2021.


Usefull links


The FM ceramic filter page - by Bruce Carter. Is a short presentation of ceramic filters theory and practical recommendations
The 10.7 MHz IF filters, is a ceramic IF filters page from the old Tuner review page. Can be downloaded Murata IF filter catalog from 1991!
Matching matters: Case study of 110 kHz narrow filters - by fmdxing. The editor of this website has modified his Denon TU-1500RD radio with 110 KHz filters in the 'narrow' tuning mode in 2006 and saw a marked improvement in reception.
How to select a FM tuner for 88-108MHz DX by Todd Emslie - a good article and tuners comparison
Receivers for FM DX recommended by New Zeeland Radio DX League
Hungarian DXers page - contains all Hungarian and its surrounding countries FM stations frequencies, propagation info etc. Just in Hungarian
Tuner Information Center is a good collection of vintage stereo tuners.
Tuner Information Center has also a DIY or mod section. I highly recommend to read general DIY and modification tips, sometime made directly made for your tuner
FM Pre-Emphasis and De-Emphasis is a good explanation of de-emphasis (time contsants) used by FM transmitters in Amerika (75us) and Europe (50us).
HD Radio Self-Noise - a good page abot HD transmission used in America, and a list of tuner which are immune to this noise generated by HD transmission.
Superheterodyne Receiver - a collection of theory of superheterodyne receivers from Science Direct.
Double & Triple Conversion Superheterodyne Radios - a good explanation of double conversion reason and effect used in AM radios from Electronics Notes.



Note: If you need the owner or service manuals for above presented radios (I have almost all of them), or you see some problems on webpage, broken links, please contact me.