I am currently running a RedBear MK-60 All Tube Lead Amplifier (Mesa 6L6) through a Marshall MG 412. My problem is this:

While playing on the high gain channel, my tone will randomly switch to clean, and take a drastic cut in volume. After a period of this, the distortion will slowly come back along with the volume. Then after a while of playing the sound will become clean again. My clean channel is a completely seperate input. The only channel switching I have on this input is High gain to mid gain. Any ideas as to what my problem is?
how long have you had the amp, and when was the last time you changed the tubes?
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it sounds like a tube issue, but it could also be a number of other things.

really, i don't know.

so i'm not much help.
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