Amp problems

[Spivonious]

Playing my El Diablo tonight and notice that it occassionally would lose volume for a few seconds and then fade back up to normal. I bought it about 1.5 years ago and it's been getting a weekly heavy workout for about 2 hours at high volumes for the past few months. Still has all of the original tubes.

Took a look at the power tubes and there is what looks like dust or some other particulate matter sitting inside of the tubes up at the tip (it's a combo so the tubes are upside-down). I want to say I've noticed a little bit of a looser sound the past few weeks, but it might be my imagination.

Does this sound like a textbook "power tubes on the way out" situation?

[Spivonious]

Been Googling...is it a capacitor problem?

edit - looked at the tubes again. The power tube with the crumbs in it looks like a piece is loose when comparing it to the other power tube.

[chrisolson]

I'm not an amp expert, but it sounds like you might have ID'd the problem.

[VitaminG]

I've had a similar problem with a couple of amps, and Pete (and others here) have suggested cleaning out the loop jacks. Spray some contact cleaner into the jacks, work a plug in and out (be firm but gentle ) and see if the problem continues. Has worked for me so far.

[Spivonious]

The loop jacks theory makes sense to me, but there's nothing currently in the loop, so shouldn't it be completely bypassed?

It's probably time to get new power tubes in there anyway, so I'm going to retube and see if it goes away. The amp also supports 6L6 tubes, so I might try switching over to see if I like the sound better.

[VitaminG]

Pete suggested it when I mentioned that the only way I could stop the problem was jumpering the loop. I've since had another amp start the same thing, and the loop jack thing fixed it again.

[Spivonious]

Okay, weird thing: I had band practice last night and had no problems at all. Maybe it's related to the 30W/60W switch. I usually run 30W at home. In this amp it's not just a power reduction, it also switches from Pentode(60W) to Triode(30W). Maybe the tubes don't like being in Triode mode.

I've emailed Genz Benz and am looking for some tubes too. It came with Rubys, but it doesn't seem like I can order directly from them. What is a good Ruby reseller?