RoonBridge on Raspberry PI 2

@Steve_C @RBM how did you update Raspbian Jessie Lite to default to USB output? I am having a similar problem with a RPi2 running RoonBridge on Jessie Lite using a Quad Vena DAC.

Both the RPi2 and Quad appear in Roon’s audio settings, but when selecting the Quad or the RPi2 as a Zone, the Pi only outputs to the 3.5mm jack instead of USB (I haven’t tested the HDMI).

Any help on updating the RPi2 to output to USB audio would be appreciated.