[robm321]

On my Antique Sound Lab AQ1001DT I have a channel that keeps going out.

I swaped tubes around the different channels and norrowed it down to one of the power tubes.

When I turn the amp on, everything works fine, then the channel with the (bad?) tube makes a popping sound and loses power (according to the bias level and my ears). The amp is about 1 1/2 years old and hasn't been used all that often. Is the tube beyond hope?

 

[tkam]

Sounds like the tube is dying but it might be worth checking out the tube pins and making sure they are clean. Could be some dirt or dust thats causing intermittent contact issues.

 

[fran]

If the fault only occurs with that tube, no matter where you put it then I'd say that tells you pretty much what you need to know. If the tube doesn't die in other sockets then it must be something to do with that socket/wiring to the socket. Like tkam says, make sure the connections are clean, but if you've been inserting/pulling tubes a bit then its likely that you kinda cleaned them up already.

Let us know how you get on - hopefully its just a tube - they look like KT88s?

Fran

 

[robm321]

Yeah, KT88s.

Thanks guys!

I'll try cleaning the connections. The tube is relatively young, so hopefully it is one of the pins, otherwise I'll just get a new one. Hmmm upgrade??

 

[sacd lover]

Quote:

Originally Posted by robm321 /img/forum/go_quote.gif On my Antique Sound Lab AQ1001DT I have a channel that keeps going out. I swaped tubes around the different channels and norrowed it down to one of the power tubes. When I turn the amp on, everything works fine, then the channel with the (bad?) tube makes a popping sound and loses power (according to the bias level and my ears). The amp is about 1 1/2 years old and hasn't been used all that often. Is the tube beyond hope?

The popping sounds like the tube is arching .... you want to get the tube out of there asap before you do damage the amp.

 

[Jahn]

absolutely. replace the tube, far cheaper than fixing an amp. the Melos must have been host to about 5 bad tubes since i got it - none the fault of the amp, other than it likes to eat tubes for breakfast as a general design thing.

 

[robm321]

Thanks Jahn and SACD lover for the warning.

I'll get another tube rather than perpetuate the problem.