50 Caliber + Gain Problem

I just bought a 50 cal + head online. After using the lead channel, set for high gain, for about 10 minutes, the gain pretty much shuts down and it goes to a moderate/light overdrive. Plus, both channels are noisy. From searching through this forum, i thought that it was a preamp tube problem, so i put in some new mesa 12ax7s in v1,v2 and v3. It didn't fix the problem. The gain was great while it lasted.

Any ideas?

Check power tubes and V-5, if not that, take it to a local amp tech... Could need new caps at the very least.

brianm99 said:

I just bought a 50 cal + head online. After using the lead channel, set for high gain, for about 10 minutes, the gain pretty much shuts down and it goes to a moderate/light overdrive. Plus, both channels are noisy. From searching through this forum, i thought that it was a preamp tube problem, so i put in some new mesa 12ax7s in v1,v2 and v3. It didn't fix the problem. The gain was great while it lasted.

Any ideas?

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ALWAYS re-tube a newly purchased used amp with all NEW tubes. This will likely take care of your noise issue and gain issue. It will cost over a 100.00 but it is well worth it.

My DC-3 was having the same issue when I bought it. Turned out to be a bad P/I tube V6 (Mesa Chinese) that also took out the power tubes in the process.

I learned a long time ago to NEVER trust the tubes in a used amp. Unless they are something NOS and special, just re-tube the whole shebang and save yourself some headache.

Try cleaning the tube sockets and pots with DeOxit, or even a cheaper electronics tuner spray that you can get at Radio Shack. Take the tubes out when they are cool, obviously.