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Sansui, and Beyond
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yeoldestereo
Reply with quote  #1 
From time to time I write reviews on vintage audio components. Listen below is a review of the Sansui AU 7700 that is in the works. Feel free to post your responses.
 
REVIEW:
 
This Sansui AU 7700 was a recent acquistion on some other gear here. And I have to admit this is one fine sounding integrated power amplifier, putting out 54 WRMS into an 8 ohm load. It is powering some 87dB speakers with total ease and authority to room shaking levels.

It has been years since I have had a Sansui Integrated here and this one has been a total delight to live with. The Sansui AU 7700 was produced from 1974 to 1976 and was listed at $399.95 during those years. While not the most powerful integrated in the Sansui line up, it more than fit the bill for a wide majority of hi-fi mavens.

As was the common practice of the time the Sansui AU 7700 was fitted with a wide complement of controls.

From the front panel top row is the speaker selector switch that has on,A,B,and A + B, Tone Controls Bass, Midrange,Treble. Bi Directional Tape dubbing for two tape decks, Selector switch for Phono 1 and 2, Tuner and Aux 1 and 2.

Bottom row consist of Power Switch, headphone input and bass and treble turnover frequency switches hi and low filter with two settings each,as well as Tone Defeat switch with two settings, Loudness two settings, bass and bass/treble. Mute with -15 and -30 dB settings and Mode switch for Stereo, Reverse and Mono. The Volume/Balance control is near center of unit with a power on LED above it.

Rear Panel consists of all the inputs required of the front panel and speaker connections. Also has a switch to separate the amp from the preamp(nice touch there). In additon there is a selector for setting ohm loading for phono cartridges.

All in all a most impressive integrated amp for the time and there is little today in this format that can exceed the venerable AU 7700, except the mega buck integrateds. And most of the mega buck integrateds do not have a phono section or a headphone input! You would think so do to their lofty price points.

Having had this powered 24/7 now for several weeks, it continues to impress with its outright musical signature. Which has caught me somewhat off guard. As jaded as I am now, near 50 years into this hobby, I am still having a hard time believing how good this piece really is. For what I gave for this as a trade in value, I now feel a wee bit of guilt. I did give more than book, because of the pristine condition it was in from a cosmetic point of view, knowing I may have to service the internals, led me to offer what I did as a trade. Although I could tell that the owner was very meticulus about the unit and gear he got from me. This one had been definitely cared for over the years.

It has been tested as an amp and as a preamp as it is separable. The preamp section is quite good and very quiet and mated well with the Musical Design D 140 power amp I have here. No it doesn't have the outright transparency of a stand alone preamp. With that being said it is not a major dissappointment to use as a preamp. The overall signature is on the warm side, with just a trace of grain, but has separation and detail in spades, with great presence. The power amp section is typical of this era using darlingtons in a push pull configuration. Four of these used for each channel. As warm as this amp runs it is highly biased in Class A, although the rear heat sinks can only take about 1 or 2 watts of Class A. The power side of the Au 7700 is a delight to listen to, have not experienced any listener fatique, it just sits there and plays music and like the preamp its signature is on the warm side.
What I have found out about the tone controls is rather amazing. They are gently contured in their slopes and offer the correct amount of bias without being intrusive, same goes for the frequency turnover settings as well. At last someone designed useful tone controls, that do not over compensate and blast you out of the chair.

The Mute control is a total joy to use. Anyone using a fairly current CD Player has noticed the amount of gain these newer units put out. But with the Sansui AU 7700 with its two position Mute control of -15dB or -30dB, puts the gain of a CD Player to a more than manageable level and lets one use the Volume Control at higher levels.

For us analog mavens the Mode Control allows us to set for Stereo, Reverse and Mono. The Mono setting is useful to me as I have a lot of vinyl in Mono. Nice touch there. I also have re-discovered my headphones that I long ago put up as much of the newer gear does not have a headphone input. It is indeed nice to kick back late at night and not disturb anyone and listen to the Signet TK 22 headphones that I have had for years now. A joy renewed with the AU 7700, that feature alone may tempt me to hang on to this unit.
The overall fit and finish of the AU 7700 is superb and I find no fault with. Full metal case, no plastic here, nice weight at 28 pounds and is easy to move and set up. It is not a back breaker. I have had plenty of back breakers, this is a pleasant surprise for once. This is a well crafted integrated amp.
Listed Below Is the Music Used For Evaluation.

LP's

Bob James - Hands Down (Columbia FC 38067)
Hiroshima - Self Titled - (Arista MFSL1-525)
John Coltrane - Blue Train - (Blue Note BST 81577)
Wes Montgomery - Bumpin' - (Verve V6-8625)
Rickie Lee Jones - Self Titled - (Warner BSK 3296)
Wynton Marsalis - Live Blues Alley - (Columbia PC2-40675)
Eric Gale - Forecast - (KUDU Records KU 11)(CTI Records)
Kenny Burrell & Grover Washington Jr - (Blue Note BT 85106)
Earl Klugh - Finger Painting - (Blue Note MFSL 1-025)
Larry Carlton - Friends - (Warner 23834-1)
Sadao Watanabe - Autumn Blow - (Inner City IC 6064)
Doobie Brothers - Minute by Minute - (Warner BSK 3193)
Santana - Zebop - (Columbia FC37158)
Pat Metheny Group - American Garage - (ECM 1-1155)
Frederick Fennel - Cleveland Symphonic Winds - (Telarc 5038)
Paul Desmond/Jim Hall - Complete Recordings - Mosaic(MR6-120)
Time Out - Dave Brubeck Quartet (Columbia CS 8192)
Paul Desmond - Self Titled (Artist House AH - 2)

CD's

Ben Webster At The Renaissance (Contemporary Records OJCCD-390-2)
The Royal Ballet Gala Performances (Classic Compact Discs CDSCD 6065) 
Jurassic Park Motion Picture Soundtrack (MCAD 10859)
We Get Requests - The Oscar Peterson Trio (Verve 810047-2)
You Won't Forget Me - Shirley Horn (Verve 847482-2) 
On Every Street - Dire Straits (Warner Brothers 26680-2)
Trio Jeepy - Branford Marsalis (Columbia CK44199)
Paris Jazz Concert - Louis Armstrong (RTE 1001-2)
Braveheart Motion Picture Soundtrack - London Symphony Orchestra (London LC0171)
Patriot Games Motion Picture Soundtrack (RCA 07863 66051-2) 
Highlights From The Plugged Nickel - Miles Davis (Columbia CK 67377)
Private Investigations Best Of Dire Straits (HDCD) - Dire Straits (Warner Bros 49891-2)
Straight Up - Bob James Trio (Warner Bros 945956-2)
Land Of Giants - McCoy Tyner (Telarc 83576)
New York Reunion - McCoy Tyner (Chesky 5173324)
Gladiator Motion Picture Soundtrack(Decca 2894670942)
Copland - Appalachian Spring (Telarc CD 80078)
F. Fennell - Holst Suites (Telarc 80038)
Tchaikovsky - 1812 Overture (Telarc 80041)
John Williams - American Journey (Sony 89364)
Bizet - Carmen (Telarc 80048)
Live At Sweet Basil - McCoy Tyner Trio (Evidence ECD 22106-2) 

Associated Components Used With Au 7700:

Goldring GR 1.2 Turntable w/Rega RB 250 Tonearm w/Goldring Electra phono cartridge.

Polk XM Satelliate Tuner

Audio Analogue Paganini CD Player.

Sony Mini Disc Deck Model 480.

Alon Model 1 Speakers w/Black Orpheus Cables.

Belkin PF 60 Surge and Filter Protection.

Musical Design D 140 power amp

Musical Concepts Interconnects.

At its opening price the AU 7700 sold for $399.95 and when adjusted for inflation to today this unit would carry a retail price of $1,298.99. There are quite a few integrateds in the arena at the $1,300.00 mark today. And a good many have passed through here. Such as the Musical Fidelity, Audio Analogue, Music Hall, Creek, and a few others that escape memory at the moment. While not to disparage any of those units, I feel that the AU 7700 can more than hold its own with those and at its used value now the comparison is a moot point. With that being said the Classe, Krell, Sim Audio, Bryston, Levinson, and Coda are overall superior in sonic signature to the AU 7700. And they should at their price point in the pre-owned market. But keep in mind that many of the newer units do not have a phono section on board. Something to consider if you remain in analog.

The only integrated amp on hand to compare the AU 7700 with, is the venerable NAD 3020A, which remains a bench mark of integrated amps and has been for 28 years, based upon price/performance ratio. After in depth listening tests with both units it is a very difficult choice between the two. However, and I never,ever thought that the NAD 3020A could be bested. At this point I am giving the nod to the AU 7700, based upon its added flexibility. The sonic signature of both amps is way to close of a call to say which one has an edge over the other. Both will drive difficult loads and both far exceed published specifications far into their service life.

The Sansui AU 7700 was produced during the stereo wars of 1967 through 1983 or so. At this time each manufacturer was pushing the design envelope each year. It is no wonder that so many of these products have endured over the years and remain in service. High End they were not and cannot be compared in that area. But for a vast majority of hi - fi mavens equipment such as this became the basis to move further upstream in the hobby, or remain quite contented with the Sansui they have. Founder of Sansui was, Mr Kosaku Kikuchi. He was eventually forced to step down by the bankers, in 1975, as he would not compromise his products. He firmly beieved that the customer of Sansui set the standard. He always was committed to producing the best product in its class and the product lived or died by consumer response. By 1980 the decline of Sansui was evident by cost cutting measures to achieve bottom line profits. Now Sansui is only a ghost of its former glory. But in their golden years Sansui was no doubt a hall mark of hi-fi manufacturers.

The purpose of this review is quite simple - value is where you find it, regardless of date of production. In my opinion this venerable peformer would be at home in a wide variety of systems today, be it your main system or a secondary system. And like anything bought pre-owned make sure of the seller and condition of the product. If you need the complete specifications of this unit visit http://www.classicsansui.net/ where you will find posted a complete original sales brochures of the AU 7700.

While researching this unit, I was totally unaware of the continued interest in Sansui gear, and the almost cult like status these products have to this day. It is a universal world wide following, with several dedicated web sites, blogs and references. Truly amazing when you stop to think about it. Here it is some 35 years since these products were new, and they still command the attention of a world wide audience. And the Sansui Tuners is a whole topic unto itself, with its own audience.

End Review
 
Hope you enjoy the review. It has been a pleasure to revisit this stellar offering from Sansui. Although this review is in its genesis phase. Meaningful posts will be appreciated.
Rudy
Reply with quote  #2 

You´re so absolutely right and true in what you said about he AU 7700. I saw this fine piece of engineering the first time, when I was with the German Airforce stationed  in the U.S. I felt immediately in love and bought it together with the tuner TU 5500. This was in 1975 and - believe it or not- both units are still working perfectly alright to my full pleasure.

Last year I got some minor problems and brought  it for repair to a small HiFi-Shop, pretty close to my home town. The shop-owner (an elderly electronic engineer) went comletely over it und turned it into an fully renovated and perfect working amplifier. It took him about 6 months to do so, but the results were fantastic. It´s like new - optically and technically -  and he told me the following: “Go ahead and enjoy this wonderful unit for another 30 years.” And that´s what I´m intending to do, but I´m quite sure, the AU 7700 will survive me easily.

 

Thanks and best regards,

 

Rudy

Browneyez
Reply with quote  #3 
Just recently purchased an old AU-7700 from a antique hifi shop in Singapore. The shop owner almost showed me the door when I tried to bargain, perhaps he thought that someone more deserving should be getting the amp.

The amp is beautiful and in reasonably good condition. The previous owner obviously had been taking good care of it. However, Aux-2 is no longer working and the left/right balance seems a bit off as well. Is there anything i can do about it?

But it sounds absolutely wonderful! I am even using it now over my 6-months old Creek Amp, which is definitely not an easy pushover.

Cannot believe the richness of the music and the amount of details that this amplifier can produced. Sax, violins and erhu sounds full-bodied even when just a single note was being played.

I would really like to restore it if possible. Please advise if there are any schematic or blue print which i can refer to easily?

Thanks in advance

Brown
BeatleFred
Reply with quote  #4 
Thanks for taking the time to post your review of the amp.
 
As for the other person in need of the service manual, available here:
 
http://www.obsincst.com/servlet/Detail?no=73

B/F
Browneyez
Reply with quote  #5 
Finally decided to sent the AU-7700 to a tech for a look into the AUX-2.

He managed to fix that but the poor amp came back with intermittent distortion in the left channel *horrors*

Initial suspicions that a shorted transistor was the cause turned out to be unfounded, just a loose connection to the driver circuit board!

I may need some help with the bias adjustment though, the service manual indicates measure 45+- 10mA across F01 and F02? Where is F01 and F02??

Keeper
Reply with quote  #6 
Quote:
Originally Posted by Browneyez
Finally decided to sent the AU-7700 to a tech for a look into the AUX-2.

He managed to fix that but the poor amp came back with intermittent distortion in the left channel *horrors*

Initial suspicions that a shorted transistor was the cause turned out to be unfounded, just a loose connection to the driver circuit board!

I may need some help with the bias adjustment though, the service manual indicates measure 45+- 10mA across F01 and F02? Where is F01 and F02??

There are two versions of AU-7700, with and without QA Fuses.
The procedure is described in the service manual. Take a look again. (Same page)
Jim Showker
Reply with quote  #7 
I have an AU7700 that a friend found in a dumpster and gave to me about 10 years ago.   It had been treated roughly and had a whole bunch of little niggling problems that prevented it from working reliably.   I finally got it all sorted out recently.   I would have to agree, a wonderful little amp that plays so big compared to its 54 watt spec.  The comparison with the NAD 3020 is spot on.

Jim
Browneyez
Reply with quote  #8 

First of all, I would like to say a big thank you all everyone who had helped. I had opened out the bottom of the AU-7700, located the board as well as the F01 and F02. Apparently, it is just two holes in the PCB board where I can poke through to measure the ampere. (I hope I am right though!)

And the good news is after all these years, the bias current seems Ok! 0.01mA

Lolz, so at least now i know for sure that my amplifier is producing the kind of music that it was designed to do thirty years ago.

And it is really beautiful and wonderful sounds that this amp can do!

Now I am just hoping to find a matching TU-7700




 
Keeper
Reply with quote  #9 
Quote:
Originally Posted by Browneyez

First of all, I would like to say a big thank you all everyone who had helped. I had opened out the bottom of the AU-7700, located the board as well as the F01 and F02. Apparently, it is just two holes in the PCB board where I can poke through to measure the ampere. (I hope I am right though!)

And the good news is after all these years, the bias current seems Ok! 0.01mA

Lolz, so at least now i know for sure that my amplifier is producing the kind of music that it was designed to do thirty years ago.

And it is really beautiful and wonderful sounds that this amp can do!

Now I am just hoping to find a matching TU-7700




 


Bias 0.01mA ?  no no no Correct figure is 45mA

Normally checked by DMM in place of Quick Acting Fuse. In your case you have to check the same current between the red voltage wire and the PCB.
It seems that you dont have the service manual where you can see how to connect as well as the explanation (see attached text)

Attached Images
Click image for larger version - Name: AU7700Bias.jpg, Views: 203, Size: 60.88 KB 

Browneyez
Reply with quote  #10 
Quote:
Originally Posted by Keeper
Quote:
Originally Posted by Browneyez

First of all, I would like to say a big thank you all everyone who had helped. I had opened out the bottom of the AU-7700, located the board as well as the F01 and F02. Apparently, it is just two holes in the PCB board where I can poke through to measure the ampere. (I hope I am right though!)

And the good news is after all these years, the bias current seems Ok! 0.01mA

Lolz, so at least now i know for sure that my amplifier is producing the kind of music that it was designed to do thirty years ago.

And it is really beautiful and wonderful sounds that this amp can do!

Now I am just hoping to find a matching TU-7700




 


Bias 0.01mA ?  no no no Correct figure is 45mA

Normally checked by DMM in place of Quick Acting Fuse. In your case you have to check the same current between the red voltage wire and the PCB.
It seems that you dont have the service manual where you can see how to connect as well as the explanation (see attached text)


Oops...sorry I've got a typo there. The bias current was 45mA + 0.01mA.
Thanks for all the help. Perhaps I should attach some photos so others can better refer in the future

It seems like I have gotten the Sansui fever as well.

I found, and managed to listen to, the very rare Sansui AU-X1 recently here in Singapore.....and my goodness......it is certainty one of the best amplifiers that I have heard for all time


BeatleFred
Reply with quote  #11 

You mentioned the AU-X1, hmmmmm......   There is one available on Ebay now.  The seller was willing to sell it to me for a bit less than his asking price, but I declined.
 
The problem with the AU-X1 is that its a ticking time bomb. I am referring to the known Oscillation/instability issues it has. It would be great to have an AU-X1 if I knew for sure it would'nt blow up, but no seller can or would make that guarantee, so I wont take the chance of spending good money to buy one and then feel uneasy that it could suddenly go Poof at any time, and I can wave goodbye to those original Sanken transistors and all the other destroyed components on the driver board. It would then take alot of time and effort for someone with the expertise to fix it and make sure it remains stable.
 
No Thanks, Ive been there, done that.  I'll stick with the BA-5000 anyday, or B-2301

Browneyez
Reply with quote  #12 
Hi hi BeatleFred,

I just bought the AU-X1. According to the seller, it has been ticking for the past 27 years, and I can see he have been taking excellent care of it. So I hope it will continue to tick for the next 30 years? Hopefully the european version is much more stable.

And it is sounding really really good so far!

Good luck with your search for the BA-F1!

You don't happen to have the AU-X1 service manual and owner manual do you? Could you be kind enough to email me?

Thanks in advance!
BeatleFred
Reply with quote  #13 
Well, if you already bought it, I wish you good luck and hope that it continues to work properly.  You mentioned its 27 years old. Did you check the serial # in the back to confirm its an '82?  I ask because, most AU-X1's Ive seen are either '79 or '80. I wasnt sure if Sansui was still making the AU-X1 past '81.
 
I do have the manuals, brochure, etc..., but I dont have time the extra time to scan all that inforamtion and email it.  If you need it right away, you can order it on this site- see the homepage link.
 
I can send you a xerx copy I have in the postal mail, but in fairness to other people Ive made copies for in the past, as well as myself when I bought it,  I would charge for the copy and postage cost.
 
B/F
 
Louis
Reply with quote  #14 
Hi, I'm new on this forum. I'll just bought a sansui au 7700, this sound is amazing! But I notice that the knob on selector is kind of static and also tone switches are distorted too.I do have a contact but im afraid to damages the amp. Pls help! Thks
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