Interesting indeed - if a firmware change can allow digital signals to be sent to zone 2 - maybe after conversion to analog - maybe we can hope for a similar improvement for the Tape Out signals; i.e., letting them also include stuff from digital audio inputs, after being DACed, of course. Or would this require a hardware change, maybe a wiring split-off just before the volume control? That would fix one of the 990's few shortcomings.