@jimob ,
I am a little disappointed in Denafrips sending you a review that says,
ll DACs are not created equal, especially when it comes to dealing with noise, jitter and USB. For example, the Holo Audio May DAC (see review) was run through its measured paces by John Atkinson at Stereophile where he found, “In almost every way, the HoloAudio May (Level 3) is the best-measuring D/A processor I have encountered”. According to GoldenSound’s measurements and his interpretation thereof, the May DAC’s FIFO buffer did a great job of rejecting word-clock jitter. I would assume, based on its measured performance and my listening impressions, that the Holo May DAC may not need a DDC like the IRIS since it does such a great job with USB all on its own. [footnote 2]
Almost every USB DAC made today, from probably $25 and up, is asynchronous. That means that the USB data transfer is independent of the DAC clocking. Virtually every USB DAC will have a buffer/fifo now. That the reviewer is not aware of this is shocking, but I am not surprised.
Denafrips collects and distributes these reviews just like everyone else, and gladly sends them to anyone who will listen. They appear to make great products, but they are counting on the uneducated consumer (and reviewer) as much as anyone.