N9EWO's Review on the Japan Victor Co. (JVC) R-S77 "Synthesizer Stereo Receiver"
(2 samples tested for this report)
Discontinued Receiver

Model : JVC R-S77 Synthesizer Stereo Receiver
Country of Manufacture : Japan
Serial Number of Test Sample # 1 (approx.) : 076078xx
Serial Number of Test Sample # 2 (approx.) : 106149xx

First a little history of my stereo receiver purchases over the years. All are "solid state" (sorry I'm NOT a tube / valve lover). Also I'm NOT a audiophile, so separates and or high end stuff and above are not my cup of tea. I prefer to have the tuner with the amplifier in the same cabinet and I'm sure some will cringe on that statement.

My very first receiver was a Realistic (Radio Shack) STA-64 in late 1976. ONLY receiver I ever owned that did NOT have tuner "digital" readout. Mine was a "Foster" Japan made sample (the later STA-64B model was made in Korea by a clone manufacture). A big 16 watts per channel output. But it was super fun being my first stereo receiver. It did have a FET front end so the FM tuner was decent (that I remember). 


In mid 1979 we upgraded to the Realistic STA-240. This featured a green LED "Digital Readout" display along with the analog dial. 60 watts per channel so this was a step up in that department. Just before synthesizer tuners so no memories (used a real frequency counter IC). Worked well enough and still featured a neat 5 LED signal strength meter. Lever switches were flimsy and construction only so-so (but OK). Another Japan made "Foster manufactured" product and was only on the market for less than a year. By 1981 we were ready for the leap into a receiver with a Digital Synthesized tuner with memories, also moving away from Radio Shack's products. After the STA-240 we acquired our first JVC R-S77 in early 1981.


Models after the R-S77 We Owned

Sony STR-AV320 we used around 1990 for a number of years. It sounded OK and did have at least some of the desired rich bass response for music (but could have been better). It used one of those Hybrid Amplifier IC's. Ran a bit hot due to 2 power supply transistors. Direct frequency entry keyboard which was nice. Remote control that used a motorized volume control (typical for Sony in this era). Overall was decent for what it was.


"Class D" Sony STR DE-185 Bomb !! Owned one of these back "non-surround" receivers in the 2000's in my learning / research stage. Was a very nice "looking" receiver with again direct entry frequency keyboard entry. But at less than 15 pounds weight, how can it be a 100 watts per channel receiver ? That's right it was a good old "Class D" disaster amplifier and near ZERO deep bass response (even with it's loudness function in use). It used a number of relays as well which is never a reliable thing. Went out of here in short order.


Also see the JVC R-X60 and R-8V models I cover later in this report.

Why Deal With an Old "Digital" Stereo Receiver Designed in 1980 ?? / JVC's "Super A" Amplifier Design

Ever wonder where the serious rich  deep "Bass" frequency response went with newer Stereo Receivers ? Sadly when the surround sound "home theater" craze hit in the late 80's so did the full range "Music" Class AB amplifiers used in receivers.  In order to cut manufacturing cost, the use of Class D amplifiers designs were (and still are) put in play. These amplifier designs have a higher distortion level, and require a much lighter power transformer (for reduced costs). This trend started to take hold as early as the mid 80's and by 1990 was the industry normal by all manufactures. The low end Bass response GREATLY suffered if not made non existent on purpose. Here all manufactures said for low end response to make use of those excessive (overkill) and high distortion sub-woofers. Of course using any sub-woofer is NOT suitable for listening to "Music" (at least in my book it's NOT).

Now these days even the "Loudness" button has disappeared. This helped to restore the "Bass" response at lower listening levels. So for listening to "Music" these Class D amplifier receivers are all totally worthless. You might say......"well I will just use a external EQ to recover the lost low end" ? You would think that would fix that , however these Class D amplifiers are NOT made to produce the rich low end Bass response , so the owner will probably destroy the amplifiers electronics in time as it struggles to produce some "low end" and if it does at all (if not the damaging the connected speakers with it) ??

Going back a bit in stereo amplifier history, around 1979 there was a push by a number of Japanese manufactures using a tricky way of reducing amplifier distortion using Class B efficiency with the highly preferred Class A linearity. This is done by dynamically varying the bias voltage of the output stages (no.....it's still not a true "Class A" Amplifier). Sony called this "Spontaneous Twin Drive", Hitachi : "Super Linear", Technics (Panasonic) : "New Class A" , among others. JVC used the name "Super A" and in late 1980 the R-S77 was the first "Digital Tuner" receiver in their lineup to make use of this circuit. It put the Total Harmonic Distortion (THD) at a creepy 0.005 % (with 60 watts per channel).

Mind you many "so called" audio experts discount this "Super A" scheme saying it makes the amplifier musically incorrect. I must say I find this to be "total rubbish" as least with the JVC R-S77 covered here. We have owned a number of NEW Stereo Receivers (no...not separates or high end) of the late 70's into the 2000's and must say it's one of the best stereo receivers my ears have ever experienced (if not the best) . Not the perfect situation mind you, but is better with the "Super A" than without. It's extremely clean and full sounding to OUR ears.

JVC refined this with the "Dynamic Super A" design around 1985. Was advertised for improved dynamic range over just Super A. The first JVC models to offer the "Dynamic Super A - GM Circuit" was the R-X500 , R-X400 and the R-X300 and were not reliable receivers with the first try on the new circuits. Widely known for amplifier failures with only light use from excessive heat stress (also first hand friends experiences of the R-X500 model). But after owning a bit later improved RX-8V receiver with this circuit we feel the rich Bass sound was not so great anymore (but it was still much better than later models after). It also used true Class A preamp's which still made for a very HOT running amplifier and prone to failure (more later on this).

The R-S77 has this desirable DEEP BASS, and with it's built in "wide range" 5 band EQ makes for a perfect mix with the right speakers. OK this is an IMPORTANT part of this of course (common sense) : One of course MUST use large enough "decent" speakers to experience this Deep Bass" trait. We use a pair of modern low cost but still excellent (now discontinued) "Pioneer S-H253B-K" 3 way "8 inch woofer" speakers that have a bit above average bass response. These speakers still do not have the "Classic Bass" sound with ANY Class D amplifier receiver we have tried, but are excellent with the JVC R-S77. 

Note: Even JVC's "Dynamic Super A" surround sound receivers made in the 1990's and beyond also suffered worse from the lack of rich low end. I do know from friends personal experiences that JVC's amplifier reliability was even worse of a problem in this era and even right to the end as they generally also ran super hot even at idle.    

So for the JVC R-S77

The JVC R-S77 Super A "Synthesizer Stereo Receiver" was released in late 1980 for a MSRP of $ 560. in the USA. It was the top of the JVC line receiver at the time. I remember purchasing my first one in early 1981 for about $ 500. street price. These were in great demand at that time and I had to be put on a waiting list at the local dealer. Took about a month to be able to fork down the big $$'s to obtain one. Made the BIG mistake of upgrading to the R-X60 a few years later (which was actually a huge downgrade as we cover below), and made even BIGGER mistake letting the R-S77 go. Of course making the purchase of TWO used ones a few decades later as used for this report.

Size of the R-S77 is around a large 4 5/8 x 18 3/4  x 15 inches and the weight is 23.8 pounds (10.8 kg). Yes its size was a bit odd and large even today. It's front panel is made of (fairly) thick "sliver" brushed aluminum. The wood colored painted metal shell and pressed wood side panels only existed with North American versions. In Europe and Asia it was sold in a "all silver" cabinet minus any wood side panels (so was a tad less of a beast and weight). Beautiful anodized THICK steel undercarriage and it's 2 trap doors for access for bottom access for the amplifier and tuner PC boards. Audio power output rated at 60 watts per channel. 2 real tape monitors (inputs and outputs) along with one "Aux" line level input. We cannot forget the "BIG" feature of a built in 5 Band Graphic Equalizer (what JVC called "SEA"), with the nice + and - 12 db range.

FM "Synthesized" tuner section features a FET front end (MOSFET mixer) and a 5 LED signal strength meter. The old school green "Locked" LED comes in handy for indicating if any given station is on frequency. I found the FM tuner is sensitive to impedance, so to achieve it's great sensitivity one must use the right antenna and feed line even with indoor antennas. There is a 75 ohm connection but is not via a F connector (binding post and a clamp). No dial strings to have to worry about breaking of course as it has none. I'm spoiled now, so no more analog tuning for me anyway. Sorry, our tests did not include any testing of the AM (MW) section.


We have 6 memory presets (6 for FM and 6 for MW) that work well with a nice large florescent display that features a very much needed 2 step dimmer button. Bright is way too intense for our eyes and location. It's large Fujitsu florescent displays have seem to have held up well over the years (your situation could vary). Neat part of the synthesizer tuner (and anywhere else in the receiver) is there are no noisy "problem prone" switching DC to DC converters in the R-S77 for the florescent display. You sure don't see that anymore. These days that is a cheap way out to provide other operational voltages at the cost of added circuit noise.

Undocumented tip : If one moves a jumper on the right side of the tuner synthesizer board to it's other socket on North American versions (only do when off of course), one can tune in finer 50 kHz steps on FM. However here the MW-AM band is forced at 9 kHz steps only. It will also tune down lower to 87.5 MHz (only 87.9 MHz and 200 kHz steps in the USA position). We can't forget one other feature JVC included on many of it's stereo receivers in this era, the neat dual 16 Green LED power meters. It also runs generally COOL. Only a tad of excessive heat from a power supply regulator transistor and that is it.

Excellent ergonomics, layout of all mechanical type buttons and controls is superb. There are no noisy microprocessors lurking about in this receiver either. However as JVC did in the late 70 and into the mid 80's, they loved that "No Knob" design on stereo receivers and made use of "slider" controls. Of course the R-S77 has just that for it's Volume and Balance controls. These have a L-O-N-G travel area and work adequately including equal left and right levels in adjustment (also are very well made). These (and the 5 EQ sliders) needed to be PROPERLY cleaned and lubricated during restoration and more on that subject next.

You might ask, does it have a remote control ?? You have to remember the R-S77 was designed in 1979 or....so NO of course it does not.

WARNING : I will NOT be held responsible for any information that is listed here. ALL DONE AT YOUR OWN RISK !

Sample 2 Was Not Working As Received / What To Do (only IF you dare, this is for folks who have some Electronic Experience) ??

Alas the acquired "number two" R-S77 used sample was not working right when received. The left channel was indifferent (that is was flat sounding) aside from very intermittent output. Dirty switches and controls were of course part of the problem here (and can be expected being as old it is). However the main and very common bug in it's old age of this model are the solder connections with the EQ pots to it's PC board can go sour. For sure as soon as we ever so lightly touched the EQ PC board, it came back to life. So we needed to remove this board and re-solder all of these slider pot control connections. Mind you the electronics were all good in this sample (...whew !). For any sample that has been abused in it's lifetime it could very well need more TLC and parts (if available). I have seen comments around the internet that it's LONG "ON-OFF" power switch can become nonoperational in these with age, and that is a weird custom part with a second switch on the end (no problems experienced with both test samples). 

Important note on what to use to PROPERLY clean the switches and slider controls : For all of the mechanical switches we used Caig D-5 Deoxit (spray can type). Only way we found to get spray into these switches was from the front, so it was a MUST to remove the front METAL Bezel. It only has 5 screws, in fact the entire R-S77 is easy to work on. We needed to do this anyway for removal and service of the EQ board. You will have to carefully remove the small pre-amp board which sits in front of the EQ board that also plugs into it, plus the headphone jack to get it out. The EQ board has 6 total screws holding it in. It was a bit daunting to get it back in place but with a bit of patience was not a problem.


When one PROPERLY uses the D-5 for cleaning of the mechanical switches (not so easy to do as you should use the high setting on the spray can to be sure it gets in there via it's very small openings) , expect considerable over spray. So just let it run out of the bottom and in a few hours will dry away (be sure and work these switches well right after spraying). We cleaned up the leftover-overspray in the main clean up later. IMPORTANT : We did NOT (and was not required) clean any of the upper right and tuner memory buttons/switches nor the up and down TAC tuner buttons.

FYI : Service Manual for the JVC R-S77 can be downloaded on the excellent "Hi-Fi Engine" web site here (registration is required, but is free).

Important : One does NOT want to use Caig D-5 in ANY of the slider pots. It contains a solvent and will wash away the virgin lubricant (dry it out) and will lead to failure of the control. Caig "Fader Lube F5" (spray can version is fine but also comes in a less messy but more pricey liquid bottle version) is what you want to use here. If you must have that slightly restricted feel of the slider, Caig also sells "Fader Grease" (used after Fader Lube). But don't use too much of it and is a bit on the pricey side too.

As an alternative to the "Fader Lube", one can make do using Deoxit D100L as well (as suggested by Caig). This version of Deoxit has no solvent and has additional lubricant. This is what we did and worked great. Instead of spraying, we used a flattened Q-Tip and applied it right onto the slider pot tracks (much less clean up of course). Also see the links at the bottom of this review for additional information on this.

When doing the main cleanup, be sure and clean the headphone jack. With the test sample it was near non operational being extremely DIRTY. Appears it was never used in it's life before (until me) ? Take note it's ground connection is made via the mounting hole and nut of the jack (clean around it as well). Also be sure and make sure all PC board screws are tight (these can shrink with age and bad grounds), properly clean the main output speaker relay (it's the only relay in it), and also check and PROPERLY adjust the idle bias current on both channels via the service manual instructions. It is bound to be off a bit after so many years. WARNING : As it goes with ANY vintage receiver or electronics in general, electrolytic capacitors are always prone for failure with age. When in doubt, change them out !!


A Very Bad Decision : The JVC R-X60


In around 1983 the JVC R-X line appeared on the market (R-X40, R-X44 {later}, R-X60 and the R-X80). All looked very pretty and I purchased a R-X60 model for an expected upgrade (shown above). This was a very BAD decision and turned out to be severe downgrade. It sounded good enough (but yes it was lacking a bit of the R-S77's deep bass I will admit) and decent FM tuner with a pretty STEREO icon in the smaller florescent display.

But the real severe problem with the JVC "R-X60" (and all models in this series) was with the much lower quality slide volume control. Not only was the travel area much shorter and extremely STIFF, the extremely long shaft made for near impossible fine adjustment. To make matters even worse the Left and Right channels were off, so one was forced to fiddle with the Balance control to offset that. This difference varied as one turned it up as well (so constant fiddling with the balance control).  It became very frustrating in short order !! The top of the line R-X80 used a motor assisted volume control and hopefully was not an issue here (model not tested) ?

The general quality of construction that the R-S77 had all but gone too. Thick metal chassis was a thing of the past, also what was up with that idea of the cheap plastic cover on the headphone jack ?? The JVC magic was fading into the sunset fast with these slightly later models in our view and it never returned again even with the more decent RX-8V a few years later  !! 

JVC RX-8V "Dynamic Super A"

Just before we grabbed two used R-S77's, we acquired a nice condition JVC RX-8V model in the early 2000's. This advanced featured receiver boasted 3 microprocessors and the later "Dynamic Super A" amplifier (with the GM circuit).  It sounds much better over ANY Class D stuff , however the amplifier SUPER DEEP Bass response are somewhat restricted when compared to the R-S77 (but not by much). The 7 band EQ is all electronic adjustments with memories and "Spectrum Display". Is very nice, but still lacks the lower range of the older model as the EQ range is only + - 10 db range instead of + - 12 on the R-S77 (could this be some of the reason why ??). However the vertical "Class A" pre-amplifier board runs quite hot. Uses 3 of those fuse bulbs in sockets to light up the 3 LCD's (12 volt bulbs). The slider volume control was gone by this era, again using electronic adjustments just as with the EQ settings.

The stellar performance item with the RX-8V's is it's FM tuner section. It has one of the BEST (if not the best) performing FM tuners we have EVER encountered within a stereo receiver. QSC circuit or not with EXCELLENT sensitivity / selectivity and extremely low noise. It has a MPX blend / quieting circuit that is engaged automatically on weak signals, called QSC or "quieting slope circuit". It works extremely well to eliminate noise on weak stations and without reducing sound quality at all.

Downside is it also suffers from a tuner bug that plagues most of these series models by now (RX-5, RX-7, RX-8, RX-9). The cheap plastic murata trimmer capacitors fail (just like with the JRC NRD-545 Communications Receiver). So we had to replace these 2 to 10 pf value (5 of them : TC 101,102,103,104,105) with high quality ceramic ones and then do a total realignment. Service manual for similar RX-9 we found on the excellent Hi-Fi engine web site, the RX-8 uses the same tuner board. Once the repair was done it was a huge surprise on it's superb FM performance. JVC used a rats nests if ribbon cables attached with some ill conceived sockets in this receiver (as JVC did with many models these days). These connections are also notorious for being problematic and should all be checked for proper contacts. The older R-S77 uses none of these ribbon cable sockets.


Final Word : The JVC R-S77 is Worth Restoring for Very Nice "MUSIC" Stereo Receiver (if you can locate one in good condition)

If you appreciate listening to music that contains the rich "bass" sound you remember from decades ago (with the right speakers) the JVC R-S77 is a excellent choice plus the modern side of a nice digital tuner / memory presets with a generally cool operating amplifier. As long as ALL the electronics work properly and has not been severely abused, we feel the JVC R-S77 Stereo Receiver is an excellent candidate for restoration even in it's old age. JVC made quite a number of these in it's early 80's production, so used ones are still fairly easy to obtain. As with all used / vintage electronics, condition and operation can vary greatly when one finds one. I have seen some samples that look to have been thrown off a NUMBER of cliffs. So hunt carefully....enjoy !

Dave N9EWO
© N9EWO, all rights reserved
Ver 4.0

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Links / References (all Subject To Change Without Notice)

"Classic Receiver's" - R-S77 Review (May 2020)

Hi-Fi Engine (Great Source for Manuals)

How can 30-year-old stereo receivers sound better than new ones ?

Receiver Shoot-Out: Vintage vs. High-Tech

"Audio Power Amplifier Design" by Douglas Self , 5th Edition 2013 (JVC Section)

When do I use DeoxIT FaderLube?

Vintage Audio System Maintenance

JVC Dynamic Super-A and Gm Circuits

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Discontinued Product

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