"krrrrrrrrrr......." noise in Sansui Amp


New Member
Aug 11, 2009
Hello Audio people
I have a 150 watts Sansui Amp of the 1980's ( 75 RMS per channel) . It sounds great. Except for the the mild "Krrrrrrrrrrr..........." noise it makes when I place my ears close to the tweeters. The noise is not audible when there is music playing, but when there is no source connected to the Amp, I can hear this mild noise. The Amp power cord is two pin and hence there is no grounding. I tried to ground the metal body of the AMP , but that didn't help. Can you please provide a solution and advice the root cause of this problem. Thanks.
Fair warning, man...

I have a old Sansui AU-4400 (from the 70s I think). Had the same problem - low "krrrrrr" noise for a while on one channel. Then later it started to rise to an extremely loud continuous crackling noise. Even if I turned the volume control down to 0 and disconnected inputs, the noise level stayed the same. Sometimes it would go away, but it always came back. Gave it to a local electronics guy who said, looking doubtful, that he'd fixed it. When I asked him for the cause, he mumbled something about "bad output transistor" and couldn't clarify.

Weirdly, some days later, it started the crackle again. But when I turned off the amp and turned it on again later, silence. It's now been more'n eight years, and the crackle hasn't returned :confused: yet :yahoo:

Seems to've been the power amp stage, because it's unaffected by input signal or preamp controls.

Anyone out there know for sure?

- Chris
This noise could also be due to a dry soldering on the board of the amplifier, get it checked by a technician and he will be able to fix that for you.
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