Thanks Brian, the thought has occured to me that I am getting power into my RCA's somehow, but I can't for the life of my figure out how.

I do have a + and - pin for all 4 channels and I personally wired them directly into RCA's which obviously then feed to the amps.

The baffling part for me is why the 2nd amplifier would have any impact -- again, everything works terrific when only the single 4 channel amp is connected, but as soon as the 2nd amp gets in the equation, either through the pass throughs or wired directly, I get trouble. But even then, it is only if all 4 channels of RCA are used - if I use any 2 then things work fine.

I don't suppose you know a good amp repair place in Massachusetts?

d-