('73-'78)  *90 WPC in stereo (after recap)  $1600

This Marantz 4270 receiver has been professionally *serviced, recapped and restored in May 2026.  Included are the service & testing data sheets, before & after photos along with the old parts.

Labeled as a quad/stereo model, by simply flipping the switch on the back into 2-channel mode, the receiver pumps out a conservative 90 watts per channel after the recap.  It should be noted that the specs for the 4270 in 2 channel mode are comparable to (and may actually surpass) the specs for the Marantz 2270.

*Services performed in April 2006 included a complete disassembly for an intensive restoration as follows:
All switches and controls cleaned
Replaced meter and dial lamps with frosted "Cool White" LEDs
Replaced old vellum with new 220GSM / 147lb vellum  
Replaced AUX indicator lamp 
Replaced dial string 
Replaced all electrolytic capacitors on the PE01 Buffer Board 
Replaced all electrolytic capacitors on the PM01 B.T.L. Board
Replaced all electrolytic capacitors on the P400 Phono Amp Board
Replaced all electrolytic capacitors on the P800 Power Supply Board
Rebuild the P700 Power Amp Boards (x2)
Replaced all electrolytic capacitors
Test and re-thermal of output transistors
Replaced main electrolytic filter capacitors
Re-align FM front end / adjust MPX Oscillator
DC offset and bias adjusted to factory specs 
Executed final audio adjustments and performance data sheets

The Marantz 4270 is a very collectable and classic stereo receiver that (after the recap and restoration) now pushes out a minimum of 90 watts RMS per channel into 8 ohms in stereo.  At about 40 lbs, this unit is fairly heavy.  It also has a really neat feature that's called Vari-Matrix Synthesis. This allows the receiver to “synthesize” an amazing 4-channel like sound from any 2-channel (stereo) material.

NOTE:  this receiver comes with the original factory walnut veneer-on-metal case.  As shown in one of the photos and available as an option at a very affordable cost of $250, you can choose one of our hand-built, solid walnut covers that have their own unique walnut grain, no two will look alike.  They are approximately 5/8" thick on the top and sides.  No screws, they fit snug to fit over the metal case already on the unit.   This also allows easy access for service when necessary.  Please note these are NOT cases, they are snug fitting covers that fit right onto the unit.

Essential specs (after recap)
Power output: 90 WPC into 8 ohms (stereo)
                        30 WPC into 8 ohms (quad) 
THD: 0.15
Dimensions: 17.25"W x 5.5"H x 14.5"D
Weight: 41 lbs

receiver ('72-'78) 100 WPC (recapped / restored)   $1900

This Marantz 4300 receiver has been well taken care of and was professionally *serviced and restored in July 2024.  Included are the original owner's and service manuals along with all the service & testing data sheets; all the old parts are included as well.
Labeled as a quad/stereo model, by simply flipping the switch on the back into 2-channel mode, the receiver pumps out a conservative 100 watts per channel.

The service included a complete disassembly for an intensive restoration that included:

~replaced power switch S009
~replace main filter capacitors with upgraded ones
~replace fuse with correct fast blow type
~replace all dial and meter lamps with cool white frosted LED along with CD/AUX and stereo indicators
~right rear channel - Loose screw on H715 collector/heatsink. Installed 2 missing screws holding PCBA to heatsink
~left Rear channel - Smoked R741, Output transistor H004 shorted E to B. Replaced R741 and H001 thru 004 on left channel (outputs MUST be matched for proper operation in Stereo x2 mode)
~diagnosed to HE07 Tone Amp output coupling capacitor - 22uf 25v electrolytic capacitor reading high resistive/open~bias and DC offset 
~all pots, switches, inputs and outputs were chemically cleaned and fully tested.~new lamps and fuses
~replaced power switch S009
~replace fuse with correct fast blow type
~replace all dial and meter lamps with cool white frosted LED along with CD/AUX and stereo indicators
~right rear channel - Loose screw on H715 collector/heatsink. Installed 2 missing screws holding PCBA to heatsink
~service data sheets included.

The Marantz 4300 is a very collectable and classic stereo receiver that pushes out a minimum of 100 watts RMS per channel into 8 ohms in two channel mode.  The original retail price was about $1000.  At about 60 lbs , this unit is fairly heavy.

The 4300 has a really neat feature that's called Vari-Matrix Synthesis. This allows the receiver to “synthesize” an amazing 4-channel like sound from any 2-channel (stereo) material.

(mid 70's) 35 WPC  $1000

In very good cosmetic condition, fully serviced and operating perfectly, this Marantz 2235B receiver is really not much different from the 2235 except for cosmetic tweaks.  It comes with the factory metal case.  (As shown in the photos, one of our solid walnut covers is available at extra cost.)

Services included:
~DC offset and bias adjusted to factory specs 
~new indicator lamps
~replaced meter and dial lamps with new cool white LEDs (smoother blue appearance)
~new vellum installed
~all inputs/outputs/switches and controls are in perfect operating condition

After upgrading the lamps with the new style of frosted "cool white" LED's those blue numerals and VU meters look so good on this 2235B.  It's pretty well known by now that the 22 series of Marantz is certainly one of the best receiver lines ever made.

Basic specs:
Power output: 35 watts per channel into 8Ω (stereo)
Frequency response: 20Hz to 20kHz
Total harmonic distortion: 0.25%
Dimensions: 17.4"W x 5.5"H x 14"D
Weight: 24 lbs

('78-'80) 55 WPC  @ 8 / 60 WPC @ 4    $500

In very good cosmetic condition, fully serviced and tested, this Technics SA-500 has been partially recapped; the power board was the main focus for the recap.  

As the late 70's were becoming a slice of heaven for HiFi lovers, the market was bursting with fine receivers and the Technics SA-500 was one of those great mid-range designs . Not only does it perform well but it has the looks to go with it.  

As did other manufacturers in the late 70's, Technics was also getting ready to drop the analog receivers and move into the digital age but they did it in small steps (nobody wanted to shock the buyers with an overnight switch from analog to digital.)  The SA-500 was considered a hybrid because it featured digital power meters even though it was still an analog unit.

Made from late '78 to '80, it's rated very conservatively at about 55 watts per channel at 8 ohms and 60 WPC at 4 ohms.  That's good news about the 4 ohm power, it tells you the SA-500 is not afraid of running difficult 4 ohm loads.

As mentioned above, the SA-500's power level meters are digital LEDs which you can adjust via the power display button.  However, the signal and tuning strength meters are analog.

The balanced layout of the knobs and switches along with the white dial face make the Technics SA-500 a clean and sophisticated looking unit. The knobs are done nicely with a brushed aluminum top and sides with a polished accent line along the outer top edge. 

Thanks to having all new lamps installed, the SA-500 looks really mesmerizing when lit up in the evening.  This is a great receiver for anybody. Search the net and you'll be hard pressed to find anyone that dislikes this receiver. 

Essential specs:
Power output: 55 watts per channel into 8Ω (stereo)
Frequency response: 10Hz to 40kHz
THD: 0.04%
Speaker load impedance: 4 ohms minimum
Dimensions: 19"W x 6.5"H x 13"D
Weight: 26 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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('71-'73) 26 WPC  $350   *(wood cover not included)

Obtained from the original owner, this Sansui Model 2000A receiver has been completely disassembled, fully serviced and thoroughly tested.  All the dial and meter lamps have been replaced. 

NOTE: as seen in the photos, one of our optional custom-built, solid wood covers is available at an additional cost of $250

Can it really be over 50 years old?   Forget its age...it's now in excellent condition and completely functional.  Like it's often said, "they don't make 'em like this anymore". 

The Sansui 2000A was one of Sansui's earliest solid-state receivers. Although the later models were slightly improved versions, the 2000A really didn’t have any issues that required improvement.  At the time of its release in the early 70's, most of the speaker technology was built around the tube powered amps & receivers that were the norm.  Sansui was so passionate about the design of this model that a lot of owners say the 2000A still retains most of the warmth that naturally came from tubes.

It’s a very solid receiver with a clean silver faceplate, and blackout dial glass.  The interior build and exterior design of this Sansui 2000A is the true definition of "pure classy vintage HiFi".

Essential specs:
Power output: 26 watts per channel into 8Ω (stereo)
Frequency response: 20Hz to 40kHz
THD: 0.8%
Speaker load impedance: minimum 4 ohms
Dimensions: 18"W x 6"H x 13"D
Weight:  29 lbs

About Sansui...
Sansui was founded in 1947 in Tokyo, Japan.  Started as a transformer manufacturer, Sansui produced various audio products for more than fifty years.  In its heyday, (somewhere between the late '70’s and the mid-'80’s) Sansui was a well known brand all over the world.

The name “Sansui” means “Mountain and Water.”  The implicit appreciation of “Sansui” goes back more than a thousand years to the ancient China.  That was black ink drawings which depict nature, such as trees, rocks, and streams.

 A Japanese Zen monk named Sesshu who was eager to learn this technique went to China during the Ming dynasty period.  After several years, he came back to Japan and developed his own version of the “Sansui” drawing.  Sesshu tried to mix his Zen philosophy into the simplicity of the “Sansui” drawing.  He passed away at the age of 83 in 1503 leaving many masterpieces and left fundamental influences on Japanese culture.  The meaning of strength and simplicity in black and white is far beyond the level of just drawing techniques.   Almost all ancient Japanese culture has been somehow influenced by this philosophy.

When the founders of the transformer company named their company as Sansui, they must have thought about the philosophy of “Sansui” drawings, and its fundamental meanings; strength and simplicity of black ink drawing on white paper for the purpose of depicting nature mixing with the value of  life.

After Sansui retreated from the U.S. market in the late '80’s, they still kept producing some masterpieces under the “Alpha series” until 2001 when Sansui closed the corporate headquarters in Shin-Yokohama.  The irony is that Sansui may have peaked its reputation in the tube gear era with AU-111, followed by the incredible array of solid state equipment, and lost its presence in high end audiophile right after reviving the AU-111 as the "AU-111 Vintage" in 1999.

Alas, as all good things must come to an end, their Japanese website as a HiFi-manufacturer was last updated in January 2014 as they went out of business that same year. Sansui's sales had shriveled to just $270,000 by 2010. In Japan, the 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.

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('78-'80) 22 WPC    $300

Obtained locally from 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

(1980) 60 WPC  $500

In excellent cosmetic condition, fully bench *serviced and tested, this Yamaha CR-840 is simply beautiful, elegant and well-designed.  it's dark Brazilian hardwood veneer case is stunning!  

*Servicing included:
~disassembly of unit for chemical treatment of all pots & switches with Deoxit Gold and/or Faderlube
~DC offset and bias adjusted
~a complete set of brand new lamps with emerald green covers
~All inputs & outputs tested to perform perfectly
~knobs, switches and case were cleaned and now present as like new

Something unique to Yamaha is when speaking of 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."the muting and OST systems operated flawlessly" Stereo Review said, and more "The harmonic distortion of the CR-840 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.

In summing up their reaction to the CR-840, Stereo review said, "Suffice it to say that Yamaha makes it possible for a moderate-price receiver to provide performance that would have been unimaginable only a short time ago."
We have to agree that the CR-840 is certainly one stellar example in Yamaha's fine line of receivers.

Basic specs:
Power output: 60 watts per channel into 8Ω (stereo)
Frequency response: 20Hz to 20kHz
THD: 0.01%
Speaker load impedance: 4 ohms minimum
Dimensions: 21"W x 6.5"H x 15"D
Weight: 30 lbs

('76-'78) 32 WPC   $400

One of our personal favorite receivers to ever come from Yamaha....this CR-450 is in pristine cosmetic and operating condition.  The CR-450 was part of the excellent "CR" design series from Yamaha.  The CR-450 replaced the earlier CR-400. The entire lineup was just flat out gorgeous.  Besides our usual intensive bench servicing that includes all pots / switches / bias and new diodes on the board that controls the lighting. 

The conservative rating of 32 watts per channel into 8 ohms was  more robust than the later CR-420.  Power output is actually closer to 35 WPC and the output into 4 ohms is about 38 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 CR-450, 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-450 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-450, 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 section is also impressive.  Essentially, the Yamaha CR-450 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.   The teak veneer case is flawless and the brushed aluminum faceplate is literally mint!

SPECS:
Power output: 32 watts per channel into 8 ohms
Frequency response: 20Hz to 20kHz
THD: 0.05%
Speaker load impedance: 4Ω (minimum)
Dimensions: 13.1"D x 6.5"H x 18.3"W
Weight: 21 lbs

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stereo receiver / preamp ('77-'81)  $300

In excellent cosmetic condition and fully operational, this is a sweet little Advent 300 stereo receiver.  The super sensitive tuner has been recalibrated along with a partial recap of the phono stage. At first glance, it's not exactly a barn-burner since it's rated at "only" 15 watts per channel.  However, as per our choice, its primary duty (at Flat Rock HiFi) is to serve as an excellent standalone preamp.  This choice allows for the excellent performance of the *phono preamp stage to do its thing.
*Note:  The phono preamp alone is why most people purchase this receiver. There were so many technical improvements in it that Holman delivered a paper on it for the Audio Engineering Society. The Model 300 proved to be a low noise and low distortion receiver with an affordable price point.

If it were possible to devise a performance-to-appearance ratio for audio products, those of Advent Corporation would, in all likelihood, be strong contenders for top honors during the vintage era (and beyond). It's not that they don't look good, but that there has been no attempt to make them into sculptures. The value (and thus the cost) has been put inside the box and is directed at your ears and not necessarily your eyes. And, typically, the resulting sound has been very good. This is the tradition that the 300 springs from and was meant to advance; and as far as most true audiophiles are concerned, the advance had been made.

Classic Receivers website:
"Released around 1977 the Advent 300 receiver was an interesting piece of equipment. It was built to meet an affordable price point which meant that the build quality was not up to high end audio standards. However, the phono preamp stage was designed by Tom Holman of LucasFilm THX fame and is one of the better phono preamps in existence. It can hold its own even today. As you can see its design is not traditional as it does not have a long horizontal dial face but rather a geared rotary knob for tuning. It only produces 15 watts of power per channel and only has an FM tuner. The tuner gets mixed reviews with some loving it and others less enthusiastic."

Stereophile magazine (J. Gordon Holt, December, 1977)
"This receiver (Advent 300) includes a rather respectable little tuner, almost comparable to the Dyna FM-5 in performance, a 15 WPC power amplifier of passable quality, and a preamplifier section that in some ways gives some of the costliest preamps a run for their money...for the audio perfectionist who can't afford a Class A-recommended preamp, this may or may not be the ideal second-best choice...the Advent 300 is not the pot of gold at the end of the rainbow for a perfectionist, but if we were working our way there we would choose it over anything else under $300 as the most listenable stop-off on the way."

High Fidelity magazine (March 1977)
"The design of Advent's 300 is, over-all, economical and without frills. Advent's announced intention with the 300 is to make a receiver that, within its power capability, sounds as good as anything available at any price. While we cannot substantiate that claim-it is, after all, a partially subjective one we cannot dismiss it as untenable either. And that, considering the price of the product, constitutes a remarkable accomplishment."

Specs:
~One pair each of inputs for Tape, Phono, Aux.
~Switchable tuner muting.
~Tape monitor.
~Headphone output.
~Speaker switches. Mono or A+B stereo.
~Selector, volume/loudness (switchable), balance, bass, treble, AC, one switched AC outlet, DC power supply outlet (for Advent microphone preamp).
~Maximum output power: 15 WPC
~Dimensions: 15.75"W x 3.5"H x 10.5"D 


Back story:  By now (hopefully), anyone involved in the world of vintage HiFi knows that Advent was founded by audio visionary, Henry Kloss, after he left KLH in the late '60s. Kloss had a huge impact on the affordable loudspeaker category and his products have been part of the vintage audio landscape for decades.  Mr Kloss passed away in 2002.   

Advent decided in the '70s to enter the audio receiver category and the Model 300 was introduced into the market after 3 years of research trying to perfect a receiver that, as the catalog states, “most people will value under real listening conditions at home at a price well within the lower half of the current range.”   Designing any piece of audio hardware is a challenge, but it takes a very competent designer to engineer a more affordable piece of equipment that sounds good and is reliable. A lower retail price means cheaper parts and construction quality, but Advent created something rather worthwhile.   They did eliminate the AM tuner section, but then added an auxiliary input and a brand new *phono preamp designed by their Chief Electrical Engineer, Tomlinson Holman.   

If you love movies, his name should be immediately recognizable. Holman designed the very capable Holman Pre-amplifier, but he changed the movie experience as we know it with the invention of Lucasfilm THX.   Fast forward to 2023 and you would have found him at Apple developing products like the Apple AirPods Pro and leading the development of their other audio products and streaming technology. He also won an Oscar in 2001 for Scientific and Technical Achievement.   He is one of the most respected sound engineers in the world and tens of millions of people use his products every single day. 

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