Anything I have read seems to say I do not need a USB driver on a MAC, that the MAC will automatically load the correct USB driver, and this will be identified as USB 1.0. There is a USB 2.0 driver on the downloads section of this website, and that is for Windows.
But, smack in the middle of the “How to build a music server” article (http://www.psaudio.com/ps_how/how-to-build-a-music-server/) is a picture which shows “Audio Output Device: PSAudio USB 2.0”.
I am trying & failing to get my MacMini-JRiver to output DSD to my DS, and other DSD capable DACs (Benchmark DAC2HGC) via USB. I do have a copy of Bitperfect installed also.