EH Switchblade to Harmonic Jerkulator (Redux)

A request for interesting fuzz pedals on an online forum made me suggest a number of circuits. The Harmonic Jerkulator was chosen. I took a commission and built a version of Tim Escobedo's circuit (with silicon transistors and no clipping diodes) into an EH Switchblade pedal. I think it was a success, from treble boost to chunky, gated-fuzz.



It's not going to make all guitarists sound like Steve Albini, but it has a character unlike many other fuzzes and overdrives that is fun to play. I was not trying to recreate the original Harmonic Percolator (by Interfax), but to make a pedal which could give a range of tones that would have impact when used live, and would deliver useful shelving (without needing to use extra EQ) when used in a studio.

It creates plenty of hiss and rumble, and even had traces of radio ghost voices in some settings; It does a great job of distorting that is not done by digital plug-ins.

Recycling towards fuzz...

I have recently acquired some equipment from a plaster/dirt filled storage room after a recent stage area refurbishment. From the wreckage I got two chunky boxes covered in AV sockets. The enclosures were battered, and their contents a spaghetti-episode mess. I took a while to separate it all, and now I have a want to design a distortion circuit with XLR connections - A vocal muff maybe? From some old VHS gear I've also found some small transformers, diodes, and such - Maybe get an Octaver of some sort in the mix?

I imagine this could be a project with many iterations...updates as I find time.

FET Booster / Vox Tonebender Tribute

Another two circuits I found online - tweaked to have the dodgy kind of character I like.

FET Booster
This is based on Donald Tillman's circuit (read his article, "An FET Preamp Cable"). I tried four different FETs before choosing the one which produced the most interesting grit when cranked up full.

Vox Tonebender Tribute 1
Based on a layout by Richard Boop. I've tried a variety of PNPs; they're socketed as I haven't settled on a pair yet. They're all producing bright, high gain, silicon fuzz so far, which I like. The original specified germanium transistors (SFT363/SFT337).

I changed capacitor values from the originals a little on each build. I've played them through two different practice amps and they both do different jobs. The FET booster is good for clipped rhythm work and the Tonebender does heavy riffs and solo wailing well.