The distortion and S/N of modern D/A chips is much improved over that of 10 years ago.Yes, that may have improved with Delta Sigma, but they sound bland, and musically disconnected.
Proof is in what mahler123 heard in his above post compared to the old PS Digital Link MkIII.
We all know that amps can be vanishingly low in distortion just by dumping a s**t load of global feedback around them, and that totally stuffs up the sound. BUT HEY! IT MEASURES WELL!! so it must sound better?? not likely.
Compared to a little local feedback instead as Nelson Pass, Dan Agostino ect ect ect do.
Cheers George