OP-1 as Midi and tape record

Hi everyone. I know I’ve read a work around before and apologize for posting but can’t seem to find the answer. I’m using my op-1 as a Midi controller for GarageBand on iOS. I want to record GarageBand back to tape. I’ve been able to get op-1 to trigger GarageBand but it also triggers the internal sound. Turning down the volume turns down both GarageBand and the op-1. Is there a way to use the op-1 as the midi controller, connect the iPhone into Audio in and record GarageBand without triggering an internal sound ? Thank you!

Lift some silence off an empty part of the tape and drop it into the sampler synth engine.

This worked great! Thank you!!