Perhaps a further question (to avoid using optical), if an HDMI out port was included on the S3 (as is included for input on the ZD3), would that allow IIS (I squared S) to be added to the HDMI output/input of both units, via firmware upgrade down the track?
So of course the ZD3 doesn't have XLR inputs, so if the S3 doesn't have USB output, for best fidelity when using the S3 and ZA3 amps, you're effectively making the ZD3 redundant in a full Fosi highest fidelity stack- until the S3 Lite is released?
Would seem to make a lot more sense to launch...