The amps power supply is expecting AC which oscillates its signal at 60 hz. DC does not oscillate and may affect the amp because it adds noise to the circuit and some of the components respond differently to DC current vice AC current. I have seen AC get into a DC circuit because it can induce a current in wire but how DC gets into an AC circuit is beyond my electrical experience. EEMan may be better able to explain since I think he is an electrical engineer.
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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