I have iFi Nano USB. I used it with 5V power output only to the Qutest, meaning not cleaning the USB data cable. In the few minutes I tried that, I heard no difference. Additionally though, I tried the iFi Nano USB on my Mojo once, for cleaning the USB lines. The result was horrific. The sound was so bright I didn't even run it more than a few seconds. No idea what that is all about, and maybe I did something wrong. However there's not really anything to get wrong. It might be something to do with the iFi re-clocking the signal, since Chord sent for data asynchronously. I have also heard other people say the same, that iFi on the USB data line is very bright. On the power only line I hear no difference with the 5V power with Qutest. Neither when I tried it on my Mojo ages ago, for just power.