When I had my 1050 a similar sub hum problem occurred. If my sub and 1050 were on there was at times quite a loud humming coming from the sub. Strangely it was the worst in the morning; then quieted down later on; but still there. I tried different circuits, cheater plugs and power bar filters. To no avail. Then my 1050 died. I replaced it with a Panasonic digital amp. The problem has gone. No more annoying hum.