kittycasterFX Groovy Wizard Fuzz Driver

Hey groovy guitar wizards! I thought I’d share some insight into what I was trying to do when coming up with the Groovy Wizard Fuzz Driver.

Trying to make a fuzz really work has been a puzzle I’ve been trying to solve for years. I wanted something that allowed my guitar to really soar. Before I ever got into designing pedals I had a ‘70s Marshall JMP50 and bought a germanium fuzz face clone thinking I’d be in instant Hendrix-land. Nope. I plugged in and it somehow sounded thin yet flubby at the same time. I was plugged into the top left input of my four-input Marshall. I tried using the normal channel but that just sounded dark and woolly. Then I tried jumpering the channels and it was better but still not all that epic to me.
Years later, after I learned how to read schematics, I understood what was happening - the fuzz face pedal produced a lot of low end and the input of the Super Lead was acting like a severe high-pass filter, chopping off all that low end, creating a nasty, pinched sound. A lot of what I know about pedal circuits is from studying amp schematics, particularly all the various flavors of the classic Marshall circuits from the ‘60s and ‘70s. On the amp side, I realized what I needed was a shared-cathode input as opposed to the split-cathode input on my amp. The shared-cathode arrangement allowed all the low end of the fuzz to get through as opposed to how the split-cathode circuit chopped off all the frequencies below 720hz. Ok cool, but what about the fuzz? I messed around with various two transistor arrangements through the years but it wasn’t until I started seriously working on what would become the Groovy Wizard that I really deep-dived into the problem. My goal was not necessarily to make a clone of anything but to find a circuit that I could sculpt to my vision. I didn’t care about making the circuit exactly how it was in 1968 or whatever, I just wanted to be able to voice something that would sound and respond the way I heard it in my mind.

I ended up making a list of all the fuzz problems I wanted to try to solve. Here’s that list! —

• “The fuzz sounds great when I’m playing by myself but when I play with the band I get lost in the mix.”

• “The fuzz doesn’t work with a wah in the front. It barely wahs and it starts oscillating uncontrollably. It doesn’t like buffered pedals in front either - it makes my sound super harsh and thin. Yuck. It’s just too picky about where it is in the chain.”

• “The fuzz only works with single coils like on a Strat. My Les Paul sounds like mud through it. And forget about the neck pickup.”

• “The fuzz is too compressed and masks my guitar and amp with a smeared sound. And there’s not enough output on it to be loud enough. I just want that soaring lead tone, dammit!”

• “The fuzz is great for lead but completely unusable for rhythm. Chords sound like a mess and palm-mute style playing doesn’t work.”

• “I need my fuzz to have that magical clean-up from my guitar’s volume knob.”

• “My fuzz cleans up from my guitar’s volume knob but it cleans up too dark. Or too bright. I wish I could adjust that.”

• “I want the harmonic richness a fuzz can provide but I don’t want to lose the nuance of my guitar and amp.”

• “I want a fuzz that can sound great into a clean amp as well as a cranked, overdriven amp.”

• “Where’s my picking attack?!! Why does the fuzz have to blur the picking attack?!”

• “I like my dirt pedal but it only has one setting on the controls that sounds good. Why do they even bother putting knobs on it?”

• “I dream of a fuzz pedal that has a super wide gain range from clean boost, to perfect overdrive, and all the way to massive fuzz. And it has just the right controls on it to allow me to dial it in to my rig. Why has no one done that yet?!”

Yeah, quite a list, right? How many of these problems have you encountered? So why do we even bother with fuzz? Because we know there’s magic lurking in there if it could only be dialed in right - the beautiful harmonics, the responsiveness, the soaring lead tones, the organic goodness when it melts into your amp’s overdrive.

I started experimenting with a two-transistor circuit that utilized a PNP and NPN transistor. The basics of this circuit appears to have its origins in the mic preamp section of a mid-‘60s Helios console. And then it had been repurposed into a fuzz that is associated with Hendrix. I never really cared for that incarnation of the circuit though but I started messing around with it on the breadboard and after a couple months of experimentation it started coming together. One could argue that all a fuzz pedal is is a poorly biased amplifier stage with too much gain. I could certainly see by studying the mic pre version of this circuit, which was obviously designed to be clean and punchy and transparent. So I started with it like that and then I tweaked it and tweaked it until I knew what every parameter did, what each bias point did, what each bypass cap did. I probably spent a year and a half or more tuning it and fine-tuning it and fine-tuning it some more until I felt like I’d solved all the problems listed above. I tried different transistor combinations and played with the biasing. Then I tried another transistor combination, etc. etc. until I thought I had the right combination. I tested it with every guitar and amp I could get my hands on to make sure it could bring the magic with everything. I can confidently say that the Groovy Wizard circuit solves every bullet point I listed above! I call it a “fuzz driver” because it works like a good overdrive with the harmonics of a fuzz. Or maybe you could say it’s a great fuzz with the tightness of an overdrive. I think I succeeded in coming up with something that works with almost any rig and will enhance any playing style.

I never claimed to invent the wheel but I did try to make a better one!

Howard