This will be available in about six weeks.
Frank
Well if this is what is required in order to test it against the mentioned DACs, I hope they wait for it.
I wish the test was a little broader. They might be using a Mac Pro if the choices are USB/optical (I know because that is what I got). The way that electronic->optical is implemented inside the Mac could be compared to the way it is done inside, say, a Squeezebox, since one is probably better than the other. I (literally) put my money on the squeezebox, but that was mainly because I needed an interface to the collection and it's good to have a backup DAC anyway... plus the fact that it can output in optical and coax in decoupled parallel which makes it a breeze to do A/B testing of outboard DACs.
The USB test is going to be
interesting. The computer has to make the first sourcing there, RAM->USB. I have it on good off-the-record word that a Mac does not like to do this conversion, and that most other computers do not particularly like it, either since it hits the CPU harder than other methods (ethernet is light as a feather on that). However it is probably totally OK on this test since the testers are certainly not going to be doing other stuff on the computer during the test (i.e. no web browsing).
[off topic]
Now imagine that you are not an audiophile, but a computer phile (cyberphile?!). If somebody gives you an alternative between a data bus that hits the CPU 1000% (say) harder than another data bus, he might feel the same as if we are to compare a speaker cable that is run over by a bus to one that is not.
[/off topic]