need some advice regarding my Sansui AU-X501 amp

Chriz

New Member
Hi there. I just bought this old Sansui AU-X501 amplifier and it sounds great! But... after about 27/30 minutes the "protector" -connected to the powerswitch- sets in and stops the sound... Then it switches on again and keeps on playing for a wile, then the protector takes over again and so on... This happens also when I don't play any music but just leave the amp on. I am sure that my speakers are connected the right way, and they are for sure powerful enough. I 've been using Sansui for like 20 years, and never had this problem. Before taking it to the repair shop, is there anyone out there who can tell me what (most likely) the problem is, or has an idear what might be wrong? Hope it 's a minor problem... Thanx!

Chriz
 
Here are some causes for flashing
protect light:

1. DC on the output caused by fault in the output stage.

2. Shorted transistor in the protection circuit, either in the output
stage or relay drive/protection circuit.

3. Open capacitor in the protection circuit causing false tripping of
the protection circuit.

4. Open or high value emitter resistor.

By the way, your model isnt THAT old- it has the newer Sansui logo. Do you use the Source Direct switch on it?

B/F
 
Thank you for your quick reply! I 'll keep the options in mind. And yeah, I realize that, compared to the amps on this board, my amp ain't THAT old, but it seems old enough to me, specially now, when it don't works properly... But I'm sure it 'll work out fine. The repair department of the store where I bought the amp just went on vacation for about two weeks... I wanted to know what kind of problem it could be, what to expect, if it is easy to fix and so on... So I ended up on this board. I 'll write your information down, and take it to the store when I bring the amp. My ears are good enough, still, but I'm not very technical myself, so... Thanx again, and I let you know what the problem was when I get the amp back. (By the way: I still have this Sansui AU-D33 amplifier wich I bought in '84/85, there's something wrong with the volumeknob, but it 'll get me through I suppose...) Greets!
 
Oh, I forgot to mention that I don't use the source direct switch on it, when I do, is that better? Another thing that does'nt seem to work is the subsonic button, what's the function of that?...
 
The Source Direct, when activated, sends the signal through fewer circuits so there is (theoretically) better sound quality- the idea being the less circuitry a signal goes thru, the less chance there is for the signal to have noise & distortion and thus be more "pure". In the case of the AU-X501, when you use the Source Direct switch, you bypass the muting circuit, subsonic filter, and balance control.

The subsonic filter attenuates low frequencies (16 Hz) to block out any type of noise/distortion such as could be produced from playing warped records. If you arent using a turntable, then you can ignore it.

B/F
 
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