If you are having a conversation with an electrical engineer about the internal implementation of the AX8, probably not but that level of rigor usually doesn't need to apply when talking among musicians. Not to get even more mired in the details but, as Rex brought up, things get hairy when you try to compare a digital signal to an analog signal and I suspect given its effect on SPDIF that the OUT1 level is actually a calculation done before it hits that DAC. That said, the DAC and associated circuitry will convert the digital samples in a manner where 0 dBfs will hit some predictable peak voltage and my experience is that you get the strongest pro line level compatible signal with the OUT1 knob set to max. That's why I keep using the qualifier "reasonable". On analog gear, that knob would probably be a passive attenuator and people looking for "unity gain" would be looking for the answer "set it to max".
