I was just checking out some separte combos and was astonished that all most all of the pre amp/processor costs more than a full blown a/v receivers e.g. Yamaha 2400/Denon 3805. Why is that ? I'm searching for a not too expensive solution to drive the power hungry 4 ohms Polk Lsi. Whats the down side of using a slightly lower model Denon as a preprocessor and feed it to a multichannel power amplifier ? Also I'd appreciate suggestions and comments on a 7 channel power amp for less than $1500.