Everything is on the same phase; I made sure of that when wiring. I've taken that grounding course at CEDIA as well; and for the extent that I wanted to troubleshoot a DVD player I'm content to "cheat" on it until I rewire the system when I purchase a new amp.

At about the same time I solved one other ground loop problem on a satellite coax line (mistakenly grounded in two places), and for all I know that may have solved the DVD problem as well.