The missing link... Despite the fact I was able to reach more or less of a Sound Quality parity between the CCA and a USB output from a PC into a quality USB->SPDIF converter the differences were still there, the CCA was still fuzzier around higher frequency details and not as airy. Enter the iFi SPDIF iPurifier. Got one today in the mail and the improvements while not in your face are immediately apparent, the fuzziness is gone and the sound while still a bit different is as good if not better than that from the USB source. Blame the jittery output on the CCA. Now, whether or not it will have as much of an effect in your system will depend on the jitter sensitivity of the optical input of your DAC. DACs with built-in ASRC, Schiit DACs of multi-bit variety, and Delta-Sigma DACs to a lesser degree are not very likely to reveal a very noticeable improvement, but my Parasound D/AC 1000 doesn't have all those niceties and this is definitely a good investment. I'm basically confirming an earlier report from Sonic who is no longer here, so the discovery credit goes to him, but as this is very relevant to CCA having it as a part of this discussion will hopefully be useful to others.