Carvin Amp misbehaving.

[tbonesullivan]

Ok, so I will admit that my Carvin MTS combo doesn't see nearly as much use as it should since I got my Carvin V3M and Mesa DC-5. I've been using it lately, and it has started to make a strange noise, for 5-10 seconds, a tiny bit after I turn it on off standby. The sound doesn't come back once it's gone, and only seems to happen when it is still "warming up". It sounds like a dirty pot or connection, but it is not affected at all by the controls, what channel I have it on, or whether anything is actually plugged into the amplifier.

So far, I have used contact cleaner on all the jacks, and all the tube sockets and tubes. Next up is swapping out all the preamp and power tubes to see if the problem goes away.

Any other suggestions? If changing out the tubes doesn't do it, I'll probably have to take it in. It's not a particularly complicated amp so my tech should be able to fix it easily, but that's an extra expense I'd like to avoid if possible.

[HAMERMAN]

I would open it up and look for a cracked solder joint - most likely in close proximity to a tube.

[tbonesullivan]

Update: Swapped out all the preamp tubes, and I did not have an issues this time. I will use these preamp tubes for a week or so, and then slowly start re-introducing the old tubes. Hopefully I can pinpoint a bad tube. Much better than wondering what the hell is wrong with it.

If it comes back, then I'll try the power tubes. Certainly hope it isn't those, they cost a bunch more than preamp tubes.

[Montelovesco]

Goog luck! Had a similar problem with my v3m... Carvins seem to be strange... 

[gorch]

That's what I like with analog equipment of all sorts. They breeze!

[tbonesullivan]

I swapped out all the preamp tubes, and I did not have an issues this time. I will use these preamp tubes for a week or so, and then slowly start re-introducing the old tubes. Hopefully I can pinpoint a bad tube. Much better than wondering what the hell is wrong with it.  It only seems to happen while the amp is warming up.

I did have it open when I cleaned the tube sockets and everything, and I checked the connections with the power tubes. I didn't see any lifted, cracked, or dull solder joins.