chuckjaywalk wrote:
A clone of the EA Parallel Universe fuzz box. Very much fun.
Nice build. Did mine on vero a while back, it's a staple on my board, but I had a problem with it recently when I enlarged my setup.
Heads up; (Recent discovery, yesterday actually), this pedal is very input load dependant insofar as the oscillating is concerned. If you plug your guitar directly into it, turn on the oscillation, it should start to self-oscillate when the gain pot is almost maxed.
But, if you place this pedal in a complex chain, with a buffer (or buffers) in front of it, it won't see that typical guitar pickup load, and the pedal will often times fail to give that self-oscillation effect when you max the gain. The entire nature of the pedal changes, and it becomes really mushy.
My solution was to put an AMZ pickup simulator at the input to the circuit. Like this;
The toggle switch emulates either a single coil, or humbucker, the pot fine tunes the load (different pickup outputs), and the cap emulates the cable capacitance. 330pF is generally what you'll get from a 10' cable, so this is adjustable to taste. Since I always use 20' cables myself, I used a 1000pF (0.001uF) cap here.
Now, it doesn't matter where, and in what kind of chain I put this pedal now, it will always react and sound the same. I have 2 buffers before it, 40' of cable in between, and a buffer after it. It sounds and reacts exactly the same there, or if I use it direct between a guitar and an amp, no matter. I highly recommend the add-on, if big step-ups are envisioned. You could even use a rotary switch, with different caps, to emulate different cable lengths. Overkill, sure, but it all depends on your needs.
Complete article on the AMZ Pickup Simulator circuit is here;
http://www.muzique.com/lab/pickups.htm