Amp Crackles When Turned On??

[Jeff123]

When I turn my Champ on and wait for about 20 sec, it makes a small crackling sound which can be heard through the speaker. It isn't a loud crackle and it only crackles a few times upon power up, then it stops, it only seems to do it if the amp has been off for a long period of time, then turned on. Other then power up, the amp is so quiet I can't tell if it's on . Could this be a bad rectifier tube? I have a 12AX7 Telefunken, a JJ 6v6, and an old Westinghouse 5Y3 GT tube - (which has had its shares of falls and tumbles). Should I buy a new 5Y3?

Thanks for any help!

-Jeff

[Superchamp]

Try changing your tubes one by one to see if it goes away, it could be a noisy tube. I did that with my 5f2a clone which had the same problem as your champ, it had a JJ6v6 that was the culprit. Hope that's it, easy fix.

Rick

[Jeff123]

Thanks alot, im sure thats the problem, because if it was anything else, it would do it 24/7...it just does it on heat up, which leads me to believe it is a partially bad tube.

-Jeff

[brownnote]

Caps will do that too...sometimes decoupling caps will make a faint crackle/rumble when first powered up, especially if they are old, or less than premium quality.

If subbing new tubes doesn't remedy the condition, then I'd be looking at the filter caps, but probably wouldn't warrant a cap job from that symptom alone unless it was preventative maintenance.

[JoeV]

My money is on a bad power tube. I had an EL34 do that.

[LooseChange]

It crackles for a minute and stops. It never happens again unless the amp is cooled down. If the amp sounds great... Don't do a thing.

[Rawk]

It is fairly standard for new production valves to do this. This is why valve manufacturers recommend leaving the amp in standby for 1 minute at startup (if you complain about this problem to them).

Of course, you don't have a standby switch, but if it sounds good when it has warmed up, then my vote is to leave things as they are.