Hello, I have a Spring Chicken w/Dwell. When I turn the control knob back to the lowest setting it starts to feedback, and grows in volume until I move the knob clockwise about 1/4 inch. Makes no difference where the dwell control is set. Also happens if I unplug the input from an audio source, which tells me that it requires no audio signal to start the feedback. My old regular SC did not do this. Anyone? Thanks all.