I'm wondering where the hobby stands with improvements in asynch USB converters. When I acquired the microRendu I was using a Gustard U12 with the Aries mini. However in comparing it to the like XMOS chip driven iFi Nano which uses battery or USB power with the microRendu it became apparent that the AC powered Gustard U12 had less low volume clarity and some bass defects. Anyone found a non AC powered asynch USB converter that works well with the micro Rendu, better than iFi Nano?