Sansui AU-9500 vs. Sansui Seven

There are a few notes on the weird Elna CS series caps in the big cap thread, but not much else. The amp has extremely low THD at low power levels and this should be confirmed along with the signature of the noise to identify any transistor issues. Like many amps, the bias pots should be replaced if you want reliability. Clean the relay too.

Thanks Conrad. I will start by getting my hands on the service manual.
 
There are a few notes on the weird Elna CS series caps in the big cap thread, but not much else. The amp has extremely low THD at low power levels and this should be confirmed along with the signature of the noise to identify any transistor issues. Like many amps, the bias pots should be replaced if you want reliability. Clean the relay too.

I replaced the relay as well, first port of call.....did the bias pots, gave it a good birthday....
 
Well, I guess that's why the world needs more than one amp design. Now, if anybody has an unwanted spare 9500, feel free to ship it to my living room!
 
@davstev so what was your verdict? If you didn't get the 9500 I think you'd be just as happy with your Seven

I have the 9500 here! The seller auditioned it with a crappy tuner as the source, no CD player or Phono, because he was moving, or had sold them off. So, it was a basic audition, mostly to show that it was in fact working, which is was. I eagerly got it home. I tied it into my system. There is no sound. No really. I am stumped. But there's no sound. Everything is hooked up right, it powers up, the relay clicks in, and there is no sound. I have quadruple checked for stupidity in hookup errors.

I can very very very very faintly hear the CD I am trying to play, almost inaudible, in my speakers. So this verifies that something is trying to get through...

I will follow up soon once this is resolved.
 
The controls can get pretty nasty and may need several DeOxit treatments. Work all switches and controls multiple times and see if you get a hint of a signal. Make sure nobody stole the pre-out/pwr-in jumpers on the rear!
 
I know you checked the usual "stupidity errors" as you say, but since I hear music at faint volume too when the two far right switches ("tape to tape monitor" and "tape reprint") are NOT at center position on my AU-9500, I thought I would mention it ¯\_(ツ)_/¯
 
The controls can get pretty nasty and may need several DeOxit treatments. Work all switches and controls multiple times and see if you get a hint of a signal. Make sure nobody stole the pre-out/pwr-in jumpers on the rear!

Jumpers are there. Getting the deoxit out.
 
I know you checked the usual "stupidity errors" as you say, but since I hear music at faint volume too when the two far right switches ("tape to tape monitor" and "tape reprint") are NOT at center position on my AU-9500, I thought I would mention it ¯\_(ツ)_/¯

Thanks for the tip, unfortunately not so simple.

I am wondering if it might be an internal fuse.
 
Sansui AU 9500

Hi David

Please turn the volume down and make sure the Tape Monitor lever is set on SOURCE, and then turn volume up again. Are you using AUX for your CD input?
Regards.

Marc
 
Hi David

Please turn the volume down and make sure the Tape Monitor lever is set on SOURCE, and then turn volume up again. Are you using AUX for your CD input?
Regards.

Marc

I will give it a shot when I get home after work. Thanks for the suggestion but I am not sure I understand the logic behind this possible solution.

Nevertheless, I try it.

Thanks.
 
I was going to say jumper's in the back as I've done that before. Strange, it's got to be something simple as it worked when it was demo'ed. Good luck
 
It worked with a Tuner plugged into the Tuner inputs? - try connecting the CD player to the Tuner inputs?
 
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It worked with a Tuner plugged into the Tuner unputs? - try connecting the CD player to the Tuner inputs?

Worked at his house, with a tuner in the tuner inputs.

Came home...carefully....then...

Didn't work with a CD player in the tuner inputs.

Didn't work with a phono in the phono in.

tried different speaker outputs (A, B)

DID NOT transmit signal from preamp out to a power amp in on another trusty reciever (tried both speakers or headphones)...this seems like a clue.

Thing to note: extremely faint signal heard through speakers when i crank the 9500 to 12 o'clock on the dial. (and...Speakers are totally fine- tested just to be sure.)

If preamp is shot for some reason (fuse, or other), would any trace of signal come through in any way?

David
 
Internal coupling of trace signals is pretty common, so I wouldn't take anything from it. It sounds like some issue with the tone board or wiring. Probably not too difficult to fix.
 
Internal coupling of trace signals is pretty common, so I wouldn't take anything from it. It sounds like some issue with the tone board or wiring. Probably not too difficult to fix.

Tone Board, or wiring. Noted, thanks.

Can you elaborate on the wiring posiblility?

Thanks,
David
 
Tone Board, or wiring. Noted, thanks.

Can you elaborate on the wiring posiblility?

Thanks,
David

I'm just thinking a power wire or ground broke. First thing one usually does on the bench is make sure the circuit has power! Sometimes I've forgotten to do this and wasted a remarkable amount of time wondering where the signals are. :scratch2:
 
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