I have a Denon 3311ci pushing 4 Definitive BP8s(200 watts each),1 CLR 2002(250 watts) and 2 Cerwin Vega 380SEs(405 watts each). It pushes 125 watts per channel and I know I'm not getting anywhere near my speakers full potential. I want to get a preamp but I am baffled at how that exactly works...