Pretty much a stock Rat with two additional switches. The clipping switch selects between the stock silicons and a assymetric MOSFET/Shottky pair. A Earlier units is supposed to have a 1N270 germanium diode in place of the Shottky The Fat switch toggles between stock mode and Fat mode by adding a 6,8uF cap at one of the RC filters and a cap to ground at the gate of the output buffer.
....and a demo by MR. Ian Sheridan.
