The Ncore NC1200 Class D amps were the first I heard that sounded anywhere close to as good through a passive preamp as through an active or buffered preamp. With the D-Sonic you may meet your goals without a preamp. If you already own the preamp I would definitely try it both ways.
BTW, if your source is a computer, you can do room correction through your player, probably as a plug-in.
BTW, if your source is a computer, you can do room correction through your player, probably as a plug-in.