Thanks very much for your detailed reply and listening test ranking.
Just to be clear, I am not at all looking for a USB DAC. My outboard Dodson makes me very happy and we have found it hard to beat for quite some time. What I am honing in on is an USB>S/PDIF converter (don't care or mind if it has DA/AD functions or not) that:
a) Does not require drivers other than Apple's OS X Core Audio to function;
b) Does not upsample everything to 48khz (as a number of products using a certain TI series of USB chips do)
c) Will pass 24/96 data.
It would also be nice if the unit did not take its power from the USB bus, and had coax S/PDIF to start with. However, if I find one that meets criteria "a-c" above I intend to buy and send it to Steve at Empirical for some of the numerous mods like he has done on the Transit, so he can add the outboard power and coax-out if not already so equipped.
(For those just joining this thread, the reported trouble with the M-Audio units--Transit and Audiophile USB--is that the drivers they provide for Mac OS X supposedly don't stack up well in ultimate systems--see reports eleswhere.)
So edumke, while I plan to telephone Edirol and ESI/Ego Sys. next week, the last questions I guess I have for you are:
1) Does the Edirol UA-25 REQUIRE the use of their drivers or are they optional, say for accessing certain configuration features?
2) Did you choose the UA-25 over the similar UA-5 for some reason? As mentioned before, the UA-5 has an outboard power supply and a coax S/PDIF output, so surely that connection should be better than the Toslink.
3) The Waveterminal has my interest, but does not appear to pass 24/96. Some of the units that don't are using the chipset that outputs everything as 48khz (and leaving it to a cheap unit to do the non-whole-number conversion from 44.1>48khz is not desireable). Since you used the Waveterminal into your McIntosh Labs external DAC, did it (your DAC) give you any indication as to the sample rate it was locking onto? That would save opening up the little case and would be the definitive answer for all of us seeking a solution like me.
Thanks again to all.
ALEX
