Audiolab M-Dac

Hello anyone using M-Dac ? Please share your experience here, Thanks.
My current setup using Window XP with JRiver Jukebox USB to MDac to Quad 405 to P3ESR.

The MDac always have flushing buffer (4)...(3).... off and on, mostly every media that I played, is quite annoying, sound distorted whenever flushing buffer happened, according to John Westlake the designer, it's got to do with the PC USB power not stable and also the media bit stream not stable, I am cracking my head to solve this issue now....

You guys experienced this ? Please help me, Thanks.

Thanks for viewing.......this subject consider closed.
I have traded in this disappointed M-Dac with Wadia 151 PowerDAC mini.