Do you have an external interface with audio inputs? If so, use a mic in front of the speaker and send it in that way, as audio.

Yeah I know that doesn't address your question about the amp and usb..... but.... I always like to do things the way they work best and generally that's the simple, tried and true way.

Last edited by Guitarhacker; 11/15/19 06:07 AM.
You can find my music at:
www.herbhartley.com
Add nothing that adds nothing to the music.
You can make excuses or you can make progress but not both.

The magic you are looking for is in the work you are avoiding.