I assume the I2S input on the W4S DAC2 is meant to be used with the PS Audio Perfect Wave Transport, which AFAIK is the only "off the shelf" transport that transmits I2S via HDMI. It therefore seems to me that the W4S DAC2 by doing both asynch USB and I2S via HDMI is trying to be a one-box solution to compete with the Ayre QB-9/Wavelength USB DACS and the PS Audio Perfect Wave DAC at a fraction of the price ($1500 for the DAC2 vs. $2500 for the Ayre QB-9 and $3000 retail for the Perfect Wave DAC.) Whether the W4S DAC will pull off this trick remains to be seen (or, heard). I can see W4S matching the sound quality of the PW DAC since they have modded so many PS Audio Digital Link IIIs, but I am somewhat doubtful that their asynch USB solution will sound as good as that developed by Wavelength and licensed to Ayre, especially since W4S is being a little mysterious about how they developed or obtained their asynch USB technology. I do know that they did not license it from Ayre.
