I have a Yamaha A/V and am trying to add a basic Stereo Receiver Amplifier to power the outdoor sub. Currently I have RCA's from the Yamaha Pre Out Fronts to the amp's amp in. Working, but is this correct or could it be done differently (better)? Will join 4 outdoor Paradigm's and a piezo under water pool speaker. That speaker also has a seperate amp. House is 7.1. Looking for a Denon/Mythos system if anyone knows one for sale.