I measured the Sutherland 20/20 with Stereophile's loan sample of the Audio Precision SYS2722 system (see the January 2008 "As We See It" and www.ap.com). Floating the unbalanced generator gave the lowest level of measured noise; although I tried connecting the chassis of the Audio Precision and the Sutherland with a separate wire, this didn't improve the signal/noise ratios.
But before I could test the Sutherland, I had to power it up, which had me scratching my head. Although each channel has its own 48V power supply—a single-ended, switch-mode wall wart…