Here we go. I received this cable a couple months back. I made an impressions post a few days after I got it, detailing both USB as a standard, and my current experience with it. I received a little bit of backlash, both for a small clerical error I made, and some stating that the only thing I should have said was that cables don't change sound.
My blurb regarding USB said essentially that, that it was unlikely that any cable, but particularly a USB cable, would change sound. However, it is not my job to simply say what follows based on the construction of USB cables. My job is to actually listen, and from that, determine whether or not I can hear a difference. So, that's exactly what I did.
My testing setup consisted of the following: my computer as the source, with the Purist Audio Design cable running to one OLDAC, and a cheaper, standard USB cable (actually the one that came with the OLDAC) running to another OLDAC. From there, the same brand of RCA cable was run from both OLDACs into an A/B RCA switcher (this one, in particular), and then into my Neurochrome HP-1. I then had a friend of mine switch the RCA cables that went into the switcher such that I did not know which OLDAC was which state of the switcher (A or B). I then put on a test track, and listened, switching occasionally, attempting to determine which cable was which. I repeated this procedure 75 times, as I think that is a reasonable sample size to determine whether or not I could truly tell the difference between just two USB cables, especially two with an ~$1895 difference in price between them.
I'd like to thank Jude at JDS Labs for providing me an extra OLDAC to use for the purpose of this review, as he had no incentive to, aside from attempting to inform a market on a product that was not even his own. It was incredibly generous of him, as I did not have the extra cash laying around to purchase a second DAC that I would not use aside from for this review.
The results of this test are shown below, with a correct identification being identifying the Purist Audio Design cable.
Per this test, I correctly identified the Purist Audio Design cable only 52% of the time. That is sufficiently within the margin of reasonable error for me to confidently say that I could realistically determine no difference between the two cables, as it was mostly guesswork from my internal perspective. I'm sure that if I remembered more of a statistics course I took a few years ago that I could substantiate that.
Now I'm going to editorialize a little bit. I am firmly of the belief that if a product costs as much as this product does ($1900, just to reiterate), it needs to make a night-and-day difference when compared to a cheaper version of the same product. The simple reality is that, to my ears, there is no difference between this product and one of significantly lower price. It's hard for me to internally justify the reality that anyone would spend this much for a product that, when blind-tested in the most scientific way I can imagine, makes zero discernible difference to the listener in an audio chain.
This product was provided to me for review by Purist Audio Design. I am not being paid by anyone to write this review, to endorse the product reviewed, or for the content that I put in the review.