I have a great Nakamichi A/V unit (AV 8) I got on the cheap - I have been able to get very good sound going from my MacBook Pro via Toslink from the headphone jack, for a direct signal. I had been looking into DACs like the V90-DAC to give another big boost, though. But I had always been confused about processing/re-processing of signal. If I'm going straight out of the USB to the V90, say, my understanding is that the signal is only processed once it gets to the V90. But if I go out of the V90 into the Nakamichi, I understand that I would want an analog bypass option (to bypass that unit's reprocessing of the signal) which I think maybe I can get, but am not sure, nor how I would do it. Anyone know if there is a true analog bypass option on this kind of old higher-end A/V unit, and how to utilize it? It has optical inputs and RCA inputs.