I have published an extremely simple circuit which allows adjustable distortion to be applied to signals - could be useful addition to basic Theremins with no tone control.. Can accept any input levels and is almost unity gain (gain decreases slightly as distortion is increased), so one could plug it into the output of your theremin (or other instrument).
Simple distorter on Element-14 (http://www.element-14.com/community/docs/DOC-25403)
Fred.
Simple distorter on Element-14 (http://www.element-14.com/community/docs/DOC-25403)
Fred.