DC 3 volume

[ritterj1]

My Mesa Boogie DC-3 recently began dropping the volume unexpectedly -not by a huge factor - but enough to be noticed and a real pain during a gig. I have never replaced the tubes on this amp - never done any work on it at all. Checked it with two different guitars - still, drops volume - and then it comes back - 10- 15 seconds...any tips would be helpful!
thanks
jeff

 

[fdesalvo]

Ahhh, its your tubes.

 

[LHanson]

If not the tubes, try putting a patch cord across the effects loop. Sometimes, the part of the effects loop jack that shorts out the loop when it is not in use gets bad/dirty, and has to be replaced/cleaned.

 

[wolfgang6505]

I'm interested in hearing how this shakes out if it's not your tubes. But it probably is your tubes.

 

[plumptone]

Fellow DC-3 user here. It's the tubes. Start with the power tubes - get 4 brand new, and if that doesn't do it, move on to the pre-amp tubes. If you are the original owner and the tubes have never been replaced, you are probably going to have to replace them all...BUT...you are going to freak when you hear how good the amp sounds with all new glass. You'll hear it the way it sounded the day you brought it home, and remember the way it made you feel all those years ago! Good luck.

 

[TPM]

I don't have a DC-3, but I've got a Studio Series (pre-cursor to the Studio .22--2 EL84, 5 12AX7) and I've been having the same problem...I've taken it to a couple of places (including Mesa Boogie in Hollywood) and no one can figure it out...not sure if they tried new power tubes though. Frustrating as hell...just this sudden random slight drop in volume. Going to try new tubes and see what happens, I'm anxious to see how it turns out for you. Good luck.

Tom

 

[cvansickle]

It's your tubes failing, but not because they are bad. It's because your filter caps are not storing power, so they're making the tubes work too hard and as a result they are dying. Get the amp to tech and have your filter caps replaced. I had this problem witha DC-5, and I've heard of other DC-5 and DC-10 users reporting this problem too.

 

[geenads]

Did u check if your tubes were glowing or anything when the volume drops out?? I had a similiar problem with my DC 3... Two of the tubes on the left hand side (as u look at them in the back) were glowing bright orange. I changed out my power tubes with new, matched quad of JJ's and still had the problem. Had an Amp tech take a look and he found a cracked resister. He replaced it, I put my new JJ's back in and still the same problem. Then I replaced the newer JJ on the far left hand side with an older replacement tube and haven't had a problem yet... maybe it was a combo between the cracked resister and a bad "new" tube... Unfortunately, I'm probably giving up sound quality having a odd, older tube in the mix. I think i'll just get some matched Mesa 84's and see what happens.