This is video 4 of a 7 part series — El Capistan Sound on Sound looping tips. This video goes over Controlling Audio Degradation.
The Sound on Sound mode acts just like a tape loop acts when using an Echoplex. Each pass of the loop is played back and then re-recorded to the tape. This will cause regenerative tape saturation and audio degradation with each loop cycle. You have total control over this severity of the audio degradation using the tape/tone controls.
Demo by Strymon's marketing guy Ethan Tufts (AKA indie artist State Shirt):
http://stateshirt.com