Sanui AU-Alpha907 Limited - IN DA HOUSE!!!

[mjs1]

Yes czubsi. Hyperion is right. We have no access to these manuals and limited access to the late Japanese market Sansuis but would love to learn more about them. I certainly would pay for these manuals if you would offer them. Or, if you are feeling generous and have the time, post them in Digital Docs.

In any event, perhaps you can answer some questions about these amplifiers. For example, why is there a combined manual for the Alpha 907 Limited, a MOS amplifier, and the 907 XR which, I believe, is not? Are the topologies that similar?

The chronologic evolution of the MOS series was the X111 MOS Vintage (1985), the Alpha 907i MOS Limited (1987), the X1111 MOS Vintage (1988), and the Alpha 907 Limited (1994). How do these topologies compare? In particular, besides being a Limited model which suggest better finish and parts, is the design of the 907 Limited that different from the X1111?

I cannot understand the the reason, aside from a marketing tactic, for the AU 07 Anniversary (1996, 450,000 yen). Beautiful finish, more expensive parts but if you compare its specifications to those of the Alpha 907 MR (1995, 250,000 yen) or the 907 NRA (1998, 300,000 yen) it seems to come up short in comparison. I believe you yourself rated the 07 anniversary below the Alpha 907 Limited (1994, 410,00 yen), the 907MR, and the 907 NRA.

Finally, what difference have you noted between the sound of a MOS and conventional transistor late model Sansuis?

Please expound. Sansui aficionados need to know. Thank you.

Marc

 

[pete_mac]

White ravens ...

There are a number of very dedicated, hardcore Sansui enthusiasts who would benefit enormously from sharing some of those manuals, particularly where repairs or servicing is necessary.

I hope you're able to share them (even on a limited or conditional basis) to help keep more Sansuis alive and in good working order.

It would be a shame to keep them locked away where they can't be used for the purpose that Sansui's original engineers had intended.

 

[czubsi]

...

 

[czubsi]

...

 

[czubsi]

...

 

[czubsi]

...

 

[Kale]

Wow czubsi!! You really have some papers and pictures what are very interesting
Maybe it will better if you start a new thread so called "Sansui Alpha Amplifiers - things what you maybe didnt know" or something similar...

 

[pete_mac]

pete mac

Official service of Sansui closed (June 2014). Sansui never has provided instruction alpha series !!! I got them, provided that they do not share ...

That's such a shame. Service manuals are available for most of the earlier alpha models, but just not the later stuff. Given that Sansui no longer exist (apart from being a 'brand name for sale' for whitegoods and cheap electronic devices) I can't begin to fathom why they would not want this information shared with enthusiasts to help keep these lovely amps working in tip-top condition. By requesting this, they are effectively consigning many amps to the scrap-heap in future (or, at the very least, making life VERY difficult and complex for technicians).

 

[czubsi]

...

 

[czubsi]

...

 

[Kale]

Czubsi, first of all I wish to thanks for sharing those interesting pictures, but I really must say something about yours previous post....

The important thing is here what you gave a word not to share those Service Manuals, and I can understand this. I have some very rare Sansui materials too, and I promised too to not share, and I didn’t… But please don’t say that those amplifiers are simple like a cake. You said that you fixed 911DG repaired, 907 and 907 XR MR just only with voltmeter? OK, how you tested those amplifier to be sure they are fixed? By listening? If yes, you did only a half job.
To do a good service job, at lease you MUST have a oscilloscope (good one with 100MHz), ton generator, true RMS audio voltmeter (dual channel) and distortion meter. That is must have, the next thing what is good to have audio spectrum analyzer… but having just only a volt meter is not enough.

Another, if yours words are true, that those amplifiers are very simple, so that every amateur can fix them, why Sansui made those service manuals? If that is a true, Sansui could made one or two service manuals for complete Alpha series, but not, they made a single service manual for every single model! In those service manuals are test points, test voltages, the lists parts used in amplifier, and the most important complete adjusting procedure which is not simple!!! Alpha series amplifiers has x – balanced circuits, and you should know parameters to adjust hot, cold and gnd DC offset, plus bias setting hot, bias setting cold, ant that all on the both channel!

I am not an engineer too, but I am not like you, if I don’t have a service documentation, I would not going to go into some complex service job on some amplifier, some simple service testing I would do, but not something more.

And finally, don’t understand me on the wrong way, but counting how much some models have a RIKEN resistors, and just looking the power of main transformer is not serious (I tried to be gentle) and by looking just only those two things, say what amplifier is good and what is not good… hm…

So, please don’t say that every amateur can fix those amplifier, maybe you're just lucky….
And finally if you don’t need a Service Manuals, why you get those??

I have some experience with restoration big Alpha amplifiers, so don’t think that I'm talking about those things without experience…

 

[Hyperion]

Excellent post Kale.

 

[rasenthiran]

Agree with kale,Not everyone are capable to doing this and some also fear that it can damage the equipment if its done wrong. I personally prefer someone who has the good knowledge to handle my stuff rather then regretting later.
Pete intention was very good,having this service manual helps a lot people to repair and reuse the sansui amplifier which has been abondan or faulty. I personally downloaded few service manual attached in AK and gave it to my technician to get it repaired which helps a lot. The first word some old technician will ask is "Do you have a service manual for this units" and this few people does not have access to internet and knowledge on how to use a computer. I personally feel sharing this will increase the number of users who feels and hears the great sansui amplifier sound rather then just dumped it because it is faulty.

 

[mjs1]

For a moment let's discuss sound, not manuals, appearance, cost, power,
or build, not that I don't think that these are important.

czubsi may have the most experience here.


Do any of these late model Sansuis sound differently? Does the 07 anniversary sound better than the 907 Limited, MR, NRA, or XR? Are these all about the same soundwise or does one stand out?

John (skippy124), have you had a chance to listen to the 907 Limited and compare it to your other amps?

czubsi, which have you listened to, which have you kept, which one is your favorite and why?

I don't mean to be bossy but when and where else will we have a chance to discuss the sound of these magnificent amplifiers?

Regards to all.

Marc

 

[Hyperion]

Good to get this thread back on-track - I would also be interested to hear any responses to the 'how do they sound' request posted above. :yes:

 

[stereofun]

Agreed here. By the end of the day it is all about the sound, performance and the aesthetics.

...................................................

P.s Those secret manuals - Was that a grandmothers dying wish or a corporate bulletin that went out 20 years ago from a long gone company ? After all everyone here shares their time and knowledge.

 

[Hyperion]

Agreed here. By the end of the day it is all about the sound, performance and the aesthetics.

...................................................

P.s Those secret manuals - Was that a grandmothers dying wish or a corporate bulletin that went out 20 years ago from a long gone company ? After all everyone here shares their time and knowledge.

Apparently a promise made by czubsi to Mr. Kuramochi, a representative of Sansui, and we have to have respect for that promise. Although I am of the opinion that whatever prompted the request for the manuals NOT to be shared is now defunct. The Sansui company is no more, and whatever intellectual property is contained in the manuals (circuit design) can be obtained elsewhere if anyone wanted to. However the service manuals themselves are unique, and very valuable to this community, and indeed anyone with one of these special amplifiers who wants to repair it properly. As rasenthiran alluded to - the lack of a service manual can be the sole reason why something gets put in the recycling.

Back to those listening impressions from anyone who can...

 

[czubsi]

...

 

[Kale]

Czubsi, now I see we are different worlds. Now I am going out of this kind of discussion. Really, I don’t need it…

 

[czubsi]

...