tstabno

Thank you! With the advice provided here I have figured it out. Works great. Can't believe I was trying to accomplish this with 3.5mm Y cables, adapters, etc. I was also using the audio devices setting on the MacBook Pro. You need to use the sound settings on the MacBook Pro and direct the output to the Stomp XL. Thanks for the link to the apple support KB article.

Can the Stomp XL send audio out over the USB connection? I want to connect the Stomp XL USB to my MacBook Pro and have the Stomp XL audio heard out the 3.5" audio out in the MacBook Pro. I want to do this to simultaneously hear Stomp XL guitar and songs on the MacBook Pro to dial in guitar tones. I know that I can plug the MacBook Pro into the Return Aux/In on the Stomp XL and accomplish something similar but additional cables and Stomp blocks(send/return) are required.