This is video 3 of a 7 part series — El Capistan Sound on Sound looping tips. This video goes over Carrying Over Mode A and B sounds enter Sound on Sound mode.
The Single Tape Head machine consists of three different modes, A, B, and C (with C being Sound on Sound mode). Each of these modes are essentially one machine with three different settings. Each mode shares the same tape loop, and like a tape echo machine, the tape is a fixed length. When you enter Sound on Sound mode from modes A or B, the machine is already recording, and will play back anything previously recorded to the tape loop in modes A or B. So, if you had been playing a cool drone part in mode A or B, you can enter mode C and have that part available to loop over and add other parts.
Demo by Strymon's marketing guy Ethan Tufts (AKA indie artist State Shirt):
http://stateshirt.com