Thank you all for your responses. I have tried another USB cable and two more computers and unfortunately the same problem. Michael has emailed me to send the unit back for replacement which I will do. Other than the USB problem, it looks great and the sound quality over optical to my HD 800 is...

I have received DACMini today. The sound quality is great over optical and coax, but unfortunately I have a problem with USB. I have tried it with several computers running Windows 7, Vista and XP and on all computers I get a "This USB  device cannot be recognized". DACMini is shown as "Unknown...