I just received my Axiom 1000 7 channel amp and I'm having issues with it. The only sound I get out of my 7 channel system is a loud hum. I'm using RCA inputs, front speakers are connected to channels 1 and 2, side surrounds connected to 3 and 4, rear surround connected to 5 and 6, and center channel has one connector on channel 7. Any ideas on what is going on with my amp????