i am running 2 amps in stereo. one is a vox ac30 and the other is the marshall dsl 100h. when i am in the clean channel on the dsl i am in phase with both amps. when i select the ultra gain or 2nd channel on the dsl it goes out of phase with the ac30. sounds great with both amps except for this issue. i have inverted the phase on the speaker lead to use the lead channel with the vox so in doing that i have confirmed the phase issue.

just fyi, ive been playing for 40 years and have been a recording enginner for 35 and studio designer.. i know about phase.

any thoughts on what this might be?

love the amp btw.