Question with single rectifier amp

Hey, I bought a mesa single rectifier amp and cab setup second hand from the local guitar shop in my city. When I am playing after a few minutes or so the volume will cut out to almost nothing then after a little bit it will come back to full power. I tried changing my power tubes and switched them from the 6l6's that were in there originally to some el34s. everything was matched up right with the tubes as far as i know. Anyways, im wondering what would cause this, i brought it to the guitar shop and they didnt have the problem. could it be my cabinet?

thanks in advance.

Welcome to The Board.

Could be a preamp tube, specifically a position used as a cathode follower. Best to use JJ's, Chinese, or any NOS in those spots.

Have a read here:
http://forum.grailtone.com/viewtopic.php?f=4&t=25102&start=19

Dom

Do check the cables and jacks, it might be an easy fix.

My single rec was doing something similar around a month ago and it was the preamp tubes that needed to be changed. I put a new set in and the problem is gone. I ordered the recommended tubes from Doug's Tubes and it sounds great. I had the Russian Mesa 12AX7's in there before. I read several posts on the board about Doug's Tubes and decided to try it out and am glad I did. Good luck with the problem man.

Here is the link:
http://www.dougstubes.com/guitar-amp-tube-kits/mesa/mesa-boogie-double-rectifier-tube-kit-204.html

actually i got it fixed, but not by replacing the preamps. i had my fx mix dial at max, i took it off and the problems went away

That's cool that it was a simple fix! Glad to hear that....