Last night I was playing around with my Fender Champion 20. I'd bought the amp for portability and to have a counterpoint to my 5e3. I use several pedals with the Tweed Deluxe, among them a Joyo tremolo. I'd forgotten I'd plugged into the Champion through the pedal set, and at one point, I had the Champion's on-board tremolo effect working at the same time as I had the Joyo engaged. To my surprise, the two trem effects cycled through a pattern where they augmented each other, diminished each other, and finally cancelled each other out - and around and around again. It sounded alot like a leslie speeding up and slowing down! EUREKA!