I have been playing around using different music players and computers with my MDAC.
I have used an Intel atom based PC running Vortexbox (uses Logitec Media Server and Linux ALSA), a Windows 8.1 PC running JRiver and Foobar 2000 (both WASAPI) and a Raspberry Pi running Runeaudio (Arch Linux based). All pass the bit perfect test at 44.1kHz, 16 bit and 96kHz, 24 bit, with the original wav files and Flac encoded versions.
The Vortexbox and PC (both players) seem to sound the same to me, or at least, each time I think I've heard a difference, when I try again, it's gone! However, the Pi seems sound a little courser and less detailed. Given that all the set ups have passed the bit perfect test, this seems a little odd. It could of course be audiophile nervosa (the little £25 computer cannot be as good as the £200 atom or £400 PC and this prejudice manifests itself in a perceived difference in performance that is not actually there!), but I don't think so.
I understood that all bit perfect players should sound the same with an asynchronous DAC like the MDAC, but is this really correct?
Some companies allege that bit perfect players can sound different (e.g. JPlay:
http://www.jplay.eu), but are they just snake oil salesmen, like those who tell us that £100 USB cables are better than normal Maplin ones?
Could it be that there is some electrical noise (analogue) getting into the M-DAC from the Pi along the USB cable? I had this problem with a CDQ and solved it with a USB isolator board from Olimex.
Anyone any thoughts?