In contrast to the last two projects, this effect is just as good—if not even more impressive—when driven by instruments that output a “hotter” signal. Try it with the Cigar-Box Synthesizer (Chapter 17) or any old electric guitar you have handy—even consider using a preamp between your instrument and the Fuzztone; the hotter the signal coming in, the gnarlier the signal coming out.
Two simple modifications include changing the clipping diodes (as discussed in Step 4) and adding a power indicator LED by replacing the small SPST power switch with a DPST switch and adding the LED circuit from the Dirt-Cheap Amp (Chapter 12). Or, you might consider trading in the cheap RadioShack DPDT switch and candy tin case for a more impressive stomp box enclosure (as discussed in On Enclosures in Supplies). A good place to find those heavy-duty enclosures and stomp switches is Small Bear Electronics (http://www.smallbearelec.com/). Alternatively, search online for a small enclosure or project box made by Velleman Incorporated or Hammond Manufacturing. Likewise, Small Bear always has the fat, iconic push-on/push-off DPDT stomp switches (look in the “Stock List” section of their website under “Switches, Relays”).