In my opinion, and from experience owning both at the same time, the Adcom GFP-750 and GFA-5802 match up together very well and have a natural synergy.
They have good bass, an excellent warm midrange with outstanding vocal reproduction, and a good smooth treble.
The only thing that seemed to be somewhat lacking from this combo was ultimate top-end extension and air, and overall speed. In some ways this combo really excels, however.
I feel that the Adcom combo would be somewhat warmer, more transparent, smoother, and would have better vocal reproduction than the Parasound combo.
From experience, with the HCA-3500 power amp and the P/LD-2000 preamp, the Parasounds are probably brighter, alittle more extended on top, and may have slightly better bass extension.
What do you like and dislike about the sound of the Parasound combo?