Every component channel is reversed when one switches the channels at the speaker cables, but Mitchb may want to try exchanging the speaker cable that runs from left amp channel to left speaker with the one the runs righ amp/right speaker to eliminate the speaker cables as the culpret. Of course that only applies if he switched channels via speaker cables at the amp end. IME, its a good idea after switching channels, for whatever you are testing, to let it settle for while before making conclusions. Good luck
Hales forever,
Hales forever,