[Pierre] over on the Pure Data mailing list has a proof-of-concept working that uses the Raspi as a guitar effects processor ... tutorials and verified USB audio interfaces later.

This USB audio interface from the Austria-based ... with an XLR microphone input and a Hi-Z input for a keyboard or guitar. The interface has most of the tools you need to capture voices and ...

Furthermore, the routing options make it a powerful recording tool. Use it as a USB/MIDI guitar audio interface, sending your signal to the DAW via the multi-channel routing. “It’s even ...