I wanted to post my experience here such that it might help others.
BeagleBone Black with generic “Sabrent” USB audio sound adapter from Amazon USA. Using whatever the June 2017 release is.
First issue: Win32 disk imager did not work. I am using Win 10 32 bit, (it’s an old computer). I switched to Etcher and that solved my first problem. Yes, I was using the 32 bit version of the imager, and it works for R-pi images so it’s not totally dead. But it did not work for Volumio on the BBB.
Second issue: The response on the UI was slow, and sometimes WEB radios did not decode and I got errors. Solution: I was originally using an old class 4, 8 Gig SD card. I switched to a 32 Gig Class 10 SD card, and the operation is much smoother with no errors. (that is the only change I made to solve the slowness issue.) I did not see any minimum requirements for SD cards, but it works much better with the faster / larger one, at least for me.
other notes: If you don’t know about the reboot or reset buttons on the BeagleBone Black, the may help you. You may (or may not) need to press the reboot button when you power up the Volumio on the BBB. In particular the first time you power up with Volumio.
LEDs: the power blue LED near the power connector is on solid. After the bootup sequence (which can take a while) the LED closest to the edge of the board in the set of 4 LEDs in a row flashes like a heartbeat.
I’m very happy with Volumio, but it took some tinkering for this Newbee to get it right.