DC3 problems

[geenads]

I got a DC3 a couple of months ago and am having the following problem. I noticed my tone and volume dropped out while gigging. Looked at the back of the amp and noticed the 2 Power tubes farthest from the guitar input jack were glowing bright orange. Replaced all the power tubes with new JJs... same thing happened again last night... same tubes (the ones farthest left when looking at the tubes) glowing bright orange.. if i turn the amp on standby for a few seconds and switch it back it seems to clear up the problem (at least temporarily) any suggestions??
thanks.. (first post)

 

[plumptone]

Sorry to hear about the issues with the DC-3. I have had tube issues with mine too. I tried very hard to follow the various recommendations I was receiving in trying to figure out the problem by a process of elimination (i.e., replacing the tubes one by one.) The fastest way to figure out if it's really a tube problem is to replace all your tubes - the 84s and the AX7s. Don't forget one of the 12AX7s is also a phase splitter/driver. After I did that all my tube issues went away. Be forewarned - this amp runs HOT, and if you are playing with any regularity be prepared to change your power tubes at least every six months. Once it's working though, you'll be glad you spent the $ on a relatively simple fix. I hope that's all it is, because the DC-3 is a really great amp.

 

[geenads]

thanks for the response, guess that's my next step...until then i'll keep an eye out to see if it is only happening on either the lead, rhythm or both channels. on the heat problem.. i've heard some people blowing a fan to keep the amp cool.. thoughts?
g..

 

[Monsta-Tone]

You have Bias problems. It sounds like your amp needs to go to the doctor.

It is possible that you got a bad tube in your new set. I would try this 1st, but it is unlikely.

I would think that your Bias Supply has either a bad connection (cold solder joint), or a failed component.

If trying new Power Tubes again doesn't fix it, take it to a good tech.

These amps can be a pain to work on. A poor quality tech will cause more problems than he is worth, and can cost you more in the end if he blows something up.

The solder tabs on the board are very small, and the board is a huge pain to remove.

I have an Amp Repair business, and I would almost prefer to have Mesa work on my DC-2 so I don't have to fight it.