Help. My Peavey Classic 50 Seems to be Broken...

[jonwdowns]

hello. i just bought a used peavey classic 50 (4 x 10). when i play the amp for more than 10 minutes, it's starts making this terrible sound. It happens very suddenly...i'll be playing and then WAAAAAAAHHHHHHHH, it just starts making this loud buzzing sound and my guitar can not be heard at all. if turn the amp off, and let it relax for a bit, i am able to turn the amp on and use it for another 10 minutes or so...then it happens again. and so on.

is this tube related? is something loose? did i buy a lemon? please help me if you can.

thanks,
jon.

 

[Major Tom]

From your description, it is very possible that it is a tube, they are prone to heat-related failure, and it seems like it takes approx 10 minutes for them to get to their full operating temperature.
First, take each tube out and re-seat it in its socket to make sure you have good connections.
Get a 12ax7 preamp tube, try in each position to see if the problem goes away, if not you can do the same thing with each of the 4 power tubes.
If you can't get rid of it with tube swap, it could be either another component with a heat up problem, or a broken solder joint. Next time it does that, try shaking or pounding on it with the heel of your hand (ok, not too hard). if it goes away, or cuts in and out with the pounding, it is probably a broken solder joint.

 

[Bass Freak]

sounds like a tube to me







freak

 

[Henri Devill]

I had something similar happen with a Marshall Jubilee half stack...Dirty tube sockets if I remember


Don

 

[64Firebird]

My old Fender amp does that when the channel I'm not playing through isn't turned down all the way.