Here's an all ready wacky circuit made a touch wackier by Gwion of Holy Island Audio Effects in Wales. The main tweak they've added is... AN EFFECTS LOOP - so you can cram even MORE craziness into the noisy fuzzed out repeats this thing is known for.
I'm an admirer of Gwion's work, and have also drawn up a layout for a three oscillator drone synth that Gwion came up with that is quite evil. That one can be found on the Dirtbox Layouts blog.
The only modification I made to the Holy Island schematic was to the power supply: I used a 1n5817 protection diode in series with the 9v instead of a 1n4001 in parallel. Everything else is as it is on Gwion's schematic - which is really only a tweaked version of the Casper Electronics EchoBender. Which is a PT2399-based delay+noise design that, as far as I can tell, has been kicking around the DIY building community for over a decade.
Oh! I also changed the labeling of one parameter. The part of the circuit labeled "wet" on the schematic is called "efx" on my stripboard drawing. I gag a little when folks use the word 'wet' in reference to reverbs and delays. Sorry, I'm neurotic and weird. It can't be helped.
Someone on Dirtbox asked if I had drawn this up after I mentioned it in the comments of another post. Aside from sending this to Gwion, I realized that I hadn't shown it to anyone else... OR built it up yet. So this drawing is still UNVERIFIED.
The switch wiring is a little different from the traditional ways of connecting a 3PDT in true bypass. Gwion has the effect loop send fully grounded with the extra connection to lug three of the stomp switch.
ALSO: I feel I need to clarify the wiring on the switched send and return jacks on the effects loop. If you are using the "Cliff" style mono jacks there will be 4 lugs on each of the two jacks that need to be connected. All of the sleeve jacks (next to the jack nut) need to be connected to ground. There is a pad labeled on the board for that. You can just daisy-chain link all of them together then run one wire to that pad on the board. However - the tip lug connections are a little less obvious. The lugs that are connected to the large metal pieces on the top of the jacks are the ones that get wired to the board. They are the lugs that will be in contact when you insert the 1/4" cables for whatever pedal you want to put in the effects loop. The lugs that are on the other side of the jack are the ones that get wired to each other (referred to as "send N" and "return N"). The idea is that they will form a direct 'through' connection when there is no pedal inserted in the effects loop.
Feel free to comment and tell me how I have screwed this up! Here's the original schematic from Holy Island:
