After installing my Rotel RMB1095/RSP1066 combo, I immediately noticed a loud hum, which many of you here correctly identified as cable-induced (thanks to everyone for the help). I have an analog cable feed going to a ReplayTV 4160, and a DirectTV feed going to a Sony SAT-B55 receiver, which is connected to the ReplayTV via RCA (analog) cables and an S-video cable. When I disconnected the analog cable feed, the hum went away-even with DirectTV connected as described. However, over the past two days, the hum has come back (with cable still disconnected)-only now, it goes away when I disconnect the satellite feed. Does this make any sense? I'm not too sharp on the electrons, but if the hum is a result of different grounds for the amp (house current) and the offending device (cable or satellite), shouldn't it always be there? Can it come and go as described? Or is it a gremlin?