I would change source to a dedicated CD player such as Parasound CDC1500 I got mine new at auction for about $350 it use the Burr/Brown chipset that has become so popular. As for the Dac in your Pioneer or the Marantz, I would choose the one that you like the sound of better. After all its your ears that need to be satisfied in the end. I do agree with the others that the speakers are the most important. Have fun and happy listening.