NAD M50 Digital Music Player, M51 DAC, M52 Music Vault

Further Information: 

Stereophile review

Summing up
If you're looking for a 21st-century digital audio source and don't want to have too close a relationship with your computer, NAD's Masters Series M50, in combination with a first-rate D/A processor like NAD's own Masters Series M51, will be all you need. While the M50 can be used both with an NAS drive on the network to which it is connected and a generic USB-connected drive, the matching Masters Series M52 Music Vault is the icing on the cake. Yes, the M52 is more expensive than a home-brewed solution, but it matches the M50's and M51's styling, it's completely quiet, and, most important, its RAID 5 array guarantees that a hard-drive failure will not mean losing your music library.

Sound quality: M51
A word on the Masters Series M51 Direct Digital D/A processor would therefore be in order, given that I've been using it as one of my references since summer 2013. Jon Iverson had enthused about the M51 in his July 2012 review, concluding that he preferred DACs "that reveal as much as possible about what was captured on the tape or in the digits, and couldn't care less about adding a rose-coloured tint to dodgy digital sound. In this regard, the NAD M51 succeeds with a wonderfully detailed and revealing sound best described as honest, with a friendly smile." My own experience of the M51 (my sample was serial no. H33M5103771; his was H1XM5101162), driven by the M50 and M52, echoes Jon's. It is transparent to recorded detail without the sound becoming, in that classic phrase, "ruthlessly revealing."