I have been running in the XDA-1 into my system and so far hear a notable, but expected, improvement as compared to the analog mini output out of my Mac Mini. The unit is connected via balanced to the preamp and USB to the Mini. I have noted one gripe being that the USB connection only supports 16/48 as the maximum resolution. It has been noted previously that there may be a proprietary driver that may extend further resolution options via USB. I am hoping that this is or could be posted on Emotiva's support site.
I know I can run the optical mini to gain the resolution, but it had mentioned that drivers had been able to resolve the matter and it would certainly be nice.
Later this week should be the real test of the XDA-1 as it will go toe to toe with the Martantz SA-11S1 on red book. The Marantz will feed the digital data and also feed its analog balanced to the Pass Labs units.