Sounds like a ground loop hum. probably 60hz. Look at all your grounds and make sure they are all referenced to the same point. This includes you antenna or cable. Try disconnecting them one at a time to see it the hum goes away. If you have two different grounds of slightly different values it can set up a current which generates the hum. Plug into a dedicated power receptacle or get a power conditioner whick you plug all of your equipment into so a common ground is guaranteed.
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Music system
Model 990/7500/Magnepan 1.6 QRs/Technics SL1200 MK2/Aperion S-12 Subwoofer/OWA3/Sony NS75H DVD
APC H15 Power Conditioner

TV System
Large Advent Loudspeakers/ Polk center/Monoprice surrounds/Panasonic Viera 42 inch/Onkyo HT-RC260/Sony BDP S590/Directv


Home Theater System
Onkyo PR-SC886/Outlaw 7125 Klipsch RF-82 L/R,RC-62 center, RB-35 SR/SL, BENQ HT1075, Outlaw LFM1-EX/OPPO BDP-83/Directv
Harmony ONE
Blue Jeans and Monoprice interconnects
APC H15 Power Conditioner