[Stephen_Ri]

Dear Head-Fi members,

I have for some time had a problem with my Xian-Sheng 708B amp: noise, along with music, is coming out of the left channel. Not a steady white noise, but erratic, loud static which is fairly constant after the amp has been on about fifteen minutes. I already bought a replacement JAN 6922s, but the problem is not helped. With my old 6922s, the left one took a while to kick in (that channel did not play music, that is)--maybe ten minutes--and, of course, it still crackled after kicking in. I wonder if, during the time that channel was not playing music, something elsewhere in the circuit became overloaded. But I know little of electronics. Any ideas as to the source of this crackling would be greatly appreciated.

Stephen

 

[dcheming]

Have you replaced the 6N3 since you've been having this problem?

 

[derek8555]

Could be oxidization on the legs of the tubes or the lack of preventing it ...you can take off the tubes and rub the legs with alcohol, see if that helps.

EDIT: I also see that you are using computer as source. So try turning everything off including your computer and only leave the amp on and see if it persists, just to rule out the possibility of power contamination.

 

[Stephen_Ri]

dcheming, no I have not replaced the 6N3.

Derek, yes, I have cleaned the legs with a deoxit/lube equivalent. And have ensured against the power contamination.

Does it look like I should try buying a new 6N3, then? Might that lead to only one channel being affected?

Thanks for your suggestions so far

Stephen

 

[dcheming]

Quote:

Originally Posted by Stephen_Ri /img/forum/go_quote.gif Does it look like I should try buying a new 6N3, then? Might that lead to only one channel being affected?

The 6N3 is a dual triode tube and it acts as the gain stage for both channels, so if one of the triodes inside has gone bad it would only affect that channel. The fact that replacing the 6922s didn't fix the problem further points to the 6N3.

 

[Stephen_Ri]

The 6N3 seems to have fixed the problem. Thanks dcheming and derek for your help.

Stephen