('80-'81) 120 WPC (180 WPC @ 4)  $1100

This TOTL, 3rd generation Concept 12.0D receiver is rare, very powerful and in excellent cosmetic and operating condition.

Wrangling this beast around on the bench for servicing is always trippy!
Looking at that massive toroidal transformer is jaw dropping indeed.  The wiring and board layout is also impressive but, sometimes, just getting to the backside of the individual push buttons for intensive deoxit treatment and cleaning can be a challenge.   Patience is required...

The Concept 12.OD delivers a standard of accuracy unmarred by audible distortion. This was achieved by selecting only the best of the premium quality parts available at the time that would manage to continuously operate far below their capabilities.

The 12.0D continued the Concept tradition of stereo receivers without compromise. Every detail, from the action of the controls to the size of the internal heat sinks, was carefully crafted by a distinguished international team of designers and production engineers.  While all of the previous analog Concept models were outstanding to begin with, there are a number of design innovations make the Concept 12.0D a truly remarkable instrument.

It effortlessly pumps out a minimum of 120 watts per channel @ 8 ohms and a whopping 180 watts per channel into 4 ohm loads. All this power is because the amplifier section uses a high gain voltage amplification followed by rugged output transistors in a carefully stabilized, high speed configuration. The huge toroidal power transformer, heavy duty bridge rectifier and two 15,000 uF high-voltage electrolytic capacitors efficiently supply power for the most demanding musical passages. The result is a unit that can amplify rapidly changing audio signals while producing the lowest possible distortion.

Even though there's not much interest in listening to FM these days, the 12.0D makes it fun again.  The tuner is a marvel in itself.  This unit featured one of the earliest pure electronic tuners with a quartz crystal reference that makes precise tuning as simple as the touch of a button. Electronic memories powered by a separate circuit (no batteries!) can store up to six stations for instant access. As long as the receiver is plugged in, all digital information is kept locked in, even for the digital clock which stays on when the unit is turned off although it can be switched off if desired.

With the Concept trademark rosewood veneer case and weighing in at 51 lbs, the 12.0D features outputs for three pairs of speakers, two phono inputs with capacitive load settings and two tape/aux and a flexible tone/equalizer array for mid-bass/treble. It also has a continuously variable loudness control instead of the usual on/off switch.

Finally, the whole idea of the Concept design was to build them well enough so that the result would be consistent performance for many years of trouble free service...they succeeded.

A copy of the owner's manual is included.

About Concept...
Recognized universally as some of the very best stereo receivers ever made, the Concept receivers circuitry was designed in-house, by Dick Schram, at Pacific Stereo (late 70's California). Tom Ishimoto, former product development manager of Marantz, also had a hand in building some of the Concept line at NEC of Japan.

The bulk of the manufacturing was done by TCE, an electronics manufacturing division of Tandy Corp. (Tandy was the parent company of U.S. electronics retail chain Radio Shack). A lot of effort was made in upgrading the Concept design capabilities, and TCE's production techniques at the time were described as "terrific". Several other manufacturers were considered for the Concept receivers, but, as far as Schram was concerned, TCE was by far the best. They had gifted engineers who were excited to work on some REAL hi-fidelity audio products and became very loyal to him during the entire process.

The Concept credo was "better quality parts, operated with more margin of safety, superior circuits and no shortcuts" - that's why they last so long and still sound as good today.

More about Pacific Stereo (and Concept...) 
We (Cherry Vintage Audio) have great memories of working at Pacific Stereo in the late 60's and early 70's when there were only 3 stores, all in California: San Francisco, Berkeley and Walnut Creek. Also, it was during that time we met Dr Amar Bose who was in the early stages of demonstrating his prototype Bose 901 speakers...seeking dealers who might carry them.

Later on, the company was bought by CBS and expanded nationwide.The Concept line of stereo receivers were offered by Pacific Stereo as their top tier house brands. (in order, top to bottom: Concept, Reference by Quadraflex, Quadraflex and TransAudio) The top of the line was the Concept 16.5 (165 watts per channel, considered by many to be the best stereo receiver ever made!). Basically, when a customer went into a Pacific Stereo store looking for Pioneer, Sansui, Kenwood, etc, the salesman would steer them toward one of the "house" brands, the best of which were the Concepts.

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integrated amp & tuner (mid 70's)  50 WPC   $500/set

In excellent cosmetic and operating condition, this beautiful set of Technics SU-7700 integrated amp and ST-7300 tuner are rare birds indeed! 

Disassembled for complete servicing then reassembled for testing, both units perform perfectly.  All pots, switches, inputs, outputs, meters and lamps are 100% functional.

The thick aluminum front plates are loaded with beautiful and solid metal knobs, left/right power meters, tuning meters and a slew of switches.  Fortunately, both of these units come with beautiful, sculptured, wrap-around, factory-designed, walnut veneer cases.

Technics SU-7700 amp:
The conservatively rated power at 50 watts per channel into 4 ohms and 60 watts per channel into 8 ohms can be misleading if you just look at watts.  It's what the build quality can do with those watts and how quiet the amp section is.  When Technics built the SU-7700 they were more concerned with specs like:
~Super quiet phono equalizer circuit
~Power amp stage engineered for serious, clean power
~26 position precision ALPS attenuator (detented volume control)
~Current Mirror load in tone control (minimal noise and distortion at higher volumes)
~Extremely steep cut-off low/high filters (-12dB/oct)
The SU-7700 has  some impressive features such as an ALPS enclosed multi-stepped attenuator, robust heavy shielding signal wiring and constant current feed dual FET amplifier gain stage based on a limiter and BJT circuit.  This well built unit pulls 450 watts out of the wall (be sure and use a good surge protector!)

Specs:
Continuous power: 50 WPC (8 ohms), 60 WPC (4 ohms)
Harmonic distortion 0.08%
Speakers: 4-16 ohms
Frequency response: 5Hz to 80kHz
Tone controls:
Treble: +/- 12 dB at 20 kHz
Bass: +/- 12 dB at 50 Hz
Loudness: +8 dB at 100 Hz
Dimensions: 16"W x 5.5"H x 12.4"D
Weight: 22 lbs

Technics ST-7300 tuner:
The 7300 stereo tuner is perfectly matched to the amp in both its cosmetic design, dimensions and factory walnut case.
The 7300 is an FM/AM tuner equipped with twin meters and recording level check.  The recording level check switch is installed so that the input level of the deck can be easily adjusted.  When this switch is turned on, a 440 Hz sine wave is generated at a level corresponding to a 50% variable length FM signal input.
The front-end section is equipped with an FET with excellent high-frequency characteristics at the first stage and uses a highly accurate 3-row varicon.

('73-'75) 35 WPC  $300  (pristine)

In near perfect cosmetic condition and absolutely fully operational, this gorgeous SA-6000X was somewhere in the middle of the pack in their 2/4 (quad) lineup during the early-to-mid 70's.  (It was two spots below Technics' "king" 8500X 2/4 receiver)  The silver faceplate is flawless and dazzling with its cool green meter and myriad of lights, buttons and switches.  The factory wood case is like new as well.

The SA-6000X was produced in the mid 70's and was produced until the quad market fizzled out in about '77.  Fortunately, it's also still a fantastic stereo receiver.

The SA-6000X amplifier's final stage is set on its own vertical card with its own heatsink plugged into the main power board (besides early LSI circuits, this was considered rather high-end for 1973.)

Two small caps (by today's standards) smooth out the current obtained from the mid-sized (by 1973 standards) power transformer.

The SA-6000X sports a dual-gate MOS-Fet charged four-gang FM tuner with double differential switching MPX section.  Back in the day when quad was "the thing", an integrated demodulator was included for *CD-4 records or a "high-blend" CD-4 mode to "enhance worn out CD-4 records" (whatever that means?). 

Inputs are available for two AUX, two tape and two pairs of speakers fed by 35 watts per channel in stereo or 14 watts per channel in quad mode.

Some of the modes available on the SA-6000X tend to get people confused like Discrete, Matrix and the usual mono and stereo. Simply put, in 2-channel just using either matrix or discrete gives you a very cool synthesized quad effect from stereo sources. By the way, it sounds killer in stereo mode with ample headroom and power.

The FM tuner also allows an MPX signal to be output in view of the intended future quad broadcasts to be decoded through an external processor.  Forget that part, the tuner in stereo is just fine.

*Note: CD-4 was mainly developed by Victor Company of Japan (JVC), a brand fully owned by Matsushita since 1963.

Basic specs:
Power output: 35 WPC (stereo)
Frequency response: 8Hz to 50kHz
THD: 0.5%
Speaker load impedance: 4 ohms / 8 ohms
Dimensions: 17"W x 6"H x 15.2"D
Weight: 25 lbs

('80-'82) 30 WPC    SOLD  (recapped, restored & upgraded) 

In mint cosmetic condition and operationally fully restored, this Technics SA-202 has been recapped and upgraded. 
The servicing included replacing all the electrolytic capacitors (main filter caps, power supply, main amp, phono amp)  Also, both left/right power packs have fresh heat sink compound. The DC offset was adjusted, idle bias current adjusted and both AM/FM tuners were aligned.  All new "baby blue" LEDs were also installed.  To top it all off, it has a brand new, custom-built and beautiful solid walnut case.

The SA-202 is rated at a very conservative 30 watts per channel and was edging towards the middle of the pack in the SA series in the early 80's. It easily drives two pairs of efficient speakers and has the usual aux, phono, loudness, FM mute, tuning meter and tape inputs.  This series replaced the brushed aluminum face from the earlier versions because they went to the smooth aluminum faceplate and completely redesigned the whole front look.  

Even though it's very easy to service, that's not going to be something to worry about because, essentially, after all the restoration done to this unit, it's almost as new as it was when first released back in 1980.  

Basic specs:
Power output: 30 watts per channel into 8 ohms
Frequency response: 7Hz to 45kHz
THD: 0.04%
Speaker load impedance: 4 ohms to 16 ohms
Dimensions: 18"W x 6"H x 11"D
Weight: 16 lbs

(1977) 35 WPC   SOLD  (mint, recapped, upgraded)

In mint cosmetic condition and fully operational, this Technics SA-5270 has been recapped, completely restored and upgraded. 
The servicing included replacing all the electrolytic capacitors (main filter caps, power supply, main amp, phono amp)  Also, both left/right power packs have fresh heat sink compound. The DC offset was adjusted, idle bias current adjusted and both AM/FM tuners were aligned.  All new soft white LEDs were installed.  To top it all off, the inexpensive original case was discarded and replaced with a brand new, custom-built, sculptured and beautiful solid walnut case.

Technics was rolling in success in 1977 and the SA-5270 was one of the very popular SA-5XXX series receivers at the time.  This was right up there with the same juice as most of its main competition at the time (Pioneer SX-750, Yamaha CR-620 and Sansui G-4500)The SA-5270 was plenty powerful at it's minimum rated power of 35 watts per channel.   After the recap, the minimum rated power is now closer to 42 watts per channel without distortion. 

The 5270 easily drives two pairs of efficient speakers and has the usual aux, phono, loudness, FM mute, tuning meter and tape inputs.  This was the last of the brushed aluminum face series from Technics because, in 1978 they went to the smooth aluminum.  Also, the ribbed knobs and switches are a touch of class. Very easy to service (which won't be needed for a very long time)) and very reliable, great build, very popular vintage receiver.

Basic specs:
Power output: 35 watts per channel into 8 ohms
Frequency response: 7Hz to 50kHz
THD: 0.5%
Speaker load impedance: 4 ohms minimum
Dimensions: 17"W x 6"H x 11.6"D
Weight: 17 lbs

('78-'80)  63 WPC  SOLD  (recapped, restored)

In excellent cosmetic and working condition, this Technics SA-505 has been completely restored, recapped and seriously upgraded with a completely revamped power supply.  Although it's a labor intensive job to rip out the old STK modules and jump into a complete rebuild using discrete components, when all is said and done...it's well worth it.  Essentially, this Technics SA-505 is better than when it was new...

Gone are the old troublesome STK power packs (and related issues) because this unit has been converted with a new discrete power supply.  The servicing also included replacing all the electrolytic capacitors (main filter caps, power supply, main amp, phono amp).  The DC offset was adjusted, idle bias current adjusted and both AM/FM tuners were aligned.  All new "baby blue" LEDs were also installed. 

As a major bonus, the old worn out case was discarded and replaced with a brand new, custom-built, beautiful solid walnut case.

Features:
Bridged rectifier is used for DC rectification.
Current-mirror-loaded differential stage.
Two new 8,200 uF electrolytic capacitors in the power supply.
Outstanding S/N ratio of 73 dB  
MOS FET FM newly realigned tuner.
Flat group delay ceramic filters.
High linearity quadrature detector stage.
Phase-locked-loop multiplex stage.
LED active sensor for FM center-of-channel tuning. 2-colored, 5-point LED signal strength indicator.
"Acoustic control" with low and high frequency boost and filter switches.
Two tape monitors with two-way tape dubbing.
FM muting/mode selector.
Main/remote speaker selector.
Loudness control.
Brand new, custom-built walnut cabinet.

Essential specs:
Power output: minimum 63 watts per channel into 8 ohms (stereo)
Frequency response: 7Hz to 50kHz
THD: 0.04%
Speaker load impedance: 4 ohms to 16 ohms
Dimensions: 19"W x 6.5"H x 11.5"D
Weight: 21 lbs 

('76-'77) 165 WPC @ 8 / 205 WPC @ 4  $1300  (pristine)

This fully serviced and fully tested Technics SA-5760 stereo receiver is almost impossible to find in such excellent cosmetic and working condition as this one is. 

Essentially, it was disassembled for intensive bench cleaning, bias / offset adjustments and considerable testing prior to being offered for sale.  The upgraded, custom frosted Azure blue LEDs apply a simply stunning appearance across the faceplate when the unit is powered on...the photos do not compare when viewed in person.

Interestingly, Technics' design for the SA-5760 did not include vu-meters.  It's almost a necessity for these big monster units in order to be able to visually measure the sound output at a glance.  As a bonus, we have attached a backlit, adjustable power meter module that indicates the sound levels for both right/left speaker output.  The module has matching walnut veneer. 

At the time of its release it held the legitimate title of the "world's most powerful receiver".  Technics was enjoying a rise in the popularity of their receiver line-up in the mid 70's.  The SA-5760 was perceived as a triumph of audio engineering in the mid 70's.  

The 5760 conservatively pumps out a thunderous 165 watts per channel into 8 ohms and a whopping 205 watts per channel into 4 ohms.  All 50 lbs of this incredible beast is neatly packaged into a sleek (essentially slim) uncluttered exterior design. 

It's no secret that Technics focused on the Pioneer SX-1250 as the direct competitor to the SA-5760.  With the specs being so close to each other, Technics launched the 5760 at a slightly lower price point than the SX-1250.  

The SA-5760 was clearly in a war of fierce competition with Pioneer, Yamaha, Sansui  and all the rest.  While we have to rate them all to be excellent, we submit that the Technics SA-5760 and Pioneer's SX-1250 are closest to each other in terms of build quality and pure, unadulterated brute power.  However...to each his own opinion, right?   

In many ways you could argue that the mid-70's series of Technics gear was better built and better sounding than their later SA-XXX series that followed in the late 70's because cost-cutting was becoming the industry standard due to stiff competition.  The competition was so intense by the late 70's that everybody was cutting corners to keep up with each other.  Fortunately, the SA-5760 was available before the cost cutting measures taken by Technics took place.

Tech info:
The SA-5760 power supply features two 22,000uf caps and a gigantic laminated core transformer with dual secondaries.  All of that was to power its amplifier consisting of ‘para-push pure complimentary, direct-coupled OCL circuit with single-pack, matched differential transistors.
The SA-5760 was originally retailed at $800 in 1977 which would equate to around $4000 in 2024. This priced it very competitively against Pioneer’s S-1250 and the other "monster" receivers of the time. This budget / price angle was also heavily promoted in Technics literature at the time.

Basic specs:
Power output: 165 WPC into 8 ohms / 205 WPC into 4 ohms
Frequency response: 20Hz to 20kHz
THD: 0.08%Speaker load impedance: 4 ohms to 16 ohms
Dimensions: 21.7"W x 7"H x 19.5"D
Weight: 51 lbs

About TECHNICS / MATSUSHITA / PANASONIC...
Founded in the 1920's, the huge Japanese conglomerate Matsushita had interests in many electronics companies.  The most well known would be Technics and Panasonic. Technics was introduced as a brand name for premium loudspeakers marketed domestically by Matsushita in 1965.  Eventually, Technics became a premium brand bringing classics like the SL-1200mkii turntable and the absolute monster receiver at the top of the list: Technics SA-1000 (330 watts per channel)

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('78-'80) 22 WPC  $300

Obtained locally from the estate of the original owner, this Yamaha CR-420 is in pristine cosmetic and operating condition. 

The CR-420 is part of the "best" design series from Yamaha that included the 620, 820, etc. They were all just flat out gorgeous.  Besides our usual intensive bench servicing that includes all pots/switches/bias, it also has all new lamps and new diodes on the board that controls the lighting.  The conservative rating of 22 watts per channel into 8 ohms is closer to 25 WPC and the output into 4 ohms is 30 WPC.

Packed with all discrete components, it's late 70's design reflects the rapid improvement in receivers that made them lighter, more powerful and relatively easy to work on.  

Yamaha's famous "Natural Sound" is part of the attraction in the 420, along with the loudness compensation feature that made the Yamaha CR Series unique.  Perhaps "natural sound" is best described as having a neutral sound stage with less emphasis on colorization to the music. Of course, as usual, it's always about the quality and efficiency of the speakers but the natural sound has always been part of Yamaha's legacy.  Something else that's unique to this Yamaha series is the OTS (Optimum Tuning System), which is an easy-to-use feature that automatically locks in the exact center of the tuned channel - for the lowest possible distortion.  Stereo Review magazine once said (and still applies today) "the muting and OST systems operated flawlessly and the harmonic distortion of the CR-420 was so low that without the most advanced test instruments it would have been impossible to measure it."

Among Yamaha's most significant features is the *continuously variable loudness control. By using this control, the frequency balance and volume are adjusted simultaneously to compensate for the ear's insensitivity to high and low frequency sound at low volume settings. Thus, you can retain a natural-sounding balance regardless of listening level.
*NOTE: How does Yamaha's Loudness control work?
Theoretically, the degree of loudness compensation should vary with the listening level: The greater the reduction from "real" sonic levels, the greater the compensation. In the Yamaha CR-420, you first turn up the loudness all the way and set the volume control to the highest listening level you'd be likely to want, which will, of course, depend on your taste, the efficiency of your speakers and the acoustics and size of your room. For subsequent level adjustments, turn down the loudness, which boosts the lows and, to a smaller extent, the extreme highs relative to the midband to maintain a natural sounding balance.

When it comes to the Yamaha CR-420, all this adds up to a lot more than most could logically expect of the "low man on Yamaha's receiver lineup totem pole", even in view of their minimum performance standard policy. The tuner section is several cuts above the conventional. The phono preamp is eminently quiet, the flexibility of the rest of the preamplifier sec- tion is also impressive.  Essentially, the Yamaha CR-420 was unique in its price range. 

Main features are the outputs for two pairs of speakers, phono, FM, Aux (perfect for streaming) tape in/out.  It also has all new incandescent lamps including the light that travels with the tuning needle up and down the dial.
The teak veneer case is flawless and the brushed aluminum faceplate is literally mint!

Specs:
Power output: 25 watts per channel into 8 ohms
                     30 WPC into 4 ohms
Frequency response: 20Hz to 20kHz
THD: 0.05%
Speaker load impedance: 4Ω (minimum)
Dimensions: 12.8"D x 6.5"H x 17.8"W
Weight: 20 lbs

About Yamaha...

Yamaha is regarded as one of the largest manufacturers of audio and visual products in today’s Hi-Fi community. With their history brimming to the top of the historical timeline, here's a closer look at this manufacturer whose reputation has only grown stronger over their years of activity.

Yamaha’s creator, Mr. Torakusu Yamaha, originally started out as a manufacturer of reed organs in 1887. Back in that era Yamaha’s name was originally the Nippon Gakki Company, Ltd – translating into full English as ‘Japan Musical Instrument Manufacturing Corporation’.  Yamaha’s intriguing and renowned logo features three tuning forks at alternating angles and still remains their corporation logo today.

After the Second World War, Yamaha’s factories were re-commissioned to also manufacture motorcycles for easier travelling in the cities, and at prices people could afford – something that Yamaha is still good at doing now in all of their ventures.  Their considerable lineup of high quality vintage amps, integrated systems, receivers, turntables and speaker systems remain some of the most desirable to own by serious audiophile collectors around the world.

Yamaha progressed to even more musical instruments, including superb pianos, vibraphones, woodwind instruments, string instruments and drum kits. As their reputation in the music industry grew and grew stronger, their technological abilities followed suit. In more recent years Yamaha ventured into the world of synthesizers and samplers, setting an example to their peers in the studio environment. However, as they gained ideas within the digital sector, Yamaha established themself as a superpower in the Hi-Fi world as they engineered superb examples of Hi-Fi products; they were one of the first corporations to build a CD Recorder in 1989.

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