Another vote for the M51. My source components are the NAD M50 (which is also incredible), a HD cable box and BD/DVD player. First and foremost, the DAC sounds wonderful. Very organic sounding and lots of detail. I also really like it as a volume control. I'm using it to control a Plinius SA-103 and it makes me wonder whether I need a line stage. The amount of inputs are also a big plus. I've not seen another device like this. NAD hit a home-run with this piece.
