Does anyone have a suggestion on how to check bit accuracy on this thing?
[1] Playback a WAV from your PC through a known bit-perfect soundcard's coax out. Feed the coax out into the digital format converter's (DFC) coax input and route the DFC's optical out to your NJB3. Transfer the recorded file from your NJB3 back to your PC and run a bit comparison between the original WAV and the recorded WAV using a tool like
EAC's WAV Compare.
Note: EAC's WAV Compare only works in 44.1kHz, so run the test at 44.1kHz.
[2] Record through your UA5's analog inputs and feed the two digital outputs - optical and coax - to different devices. Feed the optical output to a known bit-perfect device (device 1) . Simultaneously feed the coax out into the DFC's coax input and route the DFC's optical out to your NJB3. Transfer device 1's recording through a known bit-perfect soundcard onto your PC, transfer the NJB3 recording to your PC, and perform
EAC's WAV Compare.
FWIW, I think the first option is an easier and better method.