This is pretty much the one thread that shows up when googling if the Benchmark Dac1 USB will work with USB from a RaspberryPi, and there is a previous comment it doesn’t, however it DOES work straight out of the box, I simply selected it in the list of DACs (Benchmark Dac 1 turned up when it was connected), and turned off i2s and voilà, sound! USB is limited to 96kbit/s / 24bit (USB 1.1 bandwidth), lower than spdif @195kbits/s. As if anyone could tell the difference?
Name: Benchmark Dac 1 USB
Receiver: no idea
DAC: Analog Devices AD1853 (according to Stereophile)
Async: I think so
Working with Volumio: YES
Tested Versions and Platforms: My RPi is a B model B+ v1.2
Harware Mixer on Volumio: NO
HW Mixer string: n/a
Comments: according to specs, the spdif/ RCA input is transformer coupled, so if one picks up spdif HAT, it doesn’t need to be transformer coupled.
Buying Link: discontinued (but well worth picking up used! Still sounds GREAT 2018, and I am using it in a high end system.)