Like you, I went from a Pioneer Elite AVR powered by separate amps and had OK 2-channel sound. When I replaced my Pioneer Elite AVR with a Marantz AV7702 home theater preamp, I was shocked at the difference. The sound was much more life-like with a better overall balance from the highs and lows. One thing I always felt I missed with my Pioneer Elite AVR was mid to low bass with my Magnepan IIIa speakers. Once the Marantz AV7702 was put into the chain, it was like my Magnepans were a completely different speaker. More mid and low bass with clearer mids and highs.