Keeley Electronics Holy Fuzz

  • By Phillip Dodge @tonereport
  • April 26, 2017


As the story goes, once upon a time (2014 to be exact), Robert Keeley stumbled upon a stash of ‘86 Matsushita germanium transistors that were perfectly suited for use in a MKIII Tone Bender circuit. Rather than just do a straight clone, Robert and Craighton added a defeatable gate control to the circuit and legend was born. They built them. They sold them. And that was the end of our story—that is, until Keeley discovered a new clutch of Mullard OC75s and set about to rebirth this white rhino of a fuzz: The Holy Fuzz.

Complete Control

With controls for Volume, Fuzz, Tone, and Gate, the Holy Fuzz seems pretty straight forward. And on some level, it is. The potentiometer for the Gate control incorporates a switch that removes it from the circuit when it’s rotated fully counterclockwise. In this position, you get nothing short of a really fantastic MKIII Tone Bender.

Bender but Better

I’ve played some pretty fantastic MKIII Tone Benders over the years. They’ve all sounded amazing at various settings, but none have sounded amazing at every setting. Some get really hissy when you fully crank up the Fuzz control. Some get impossibly dark and muddy when you dial the Fuzz back too low. And most have tone controls with just a few sweet spots. 

The Holy Fuzz is one of the few I’ve met that sounds great with just about any mix of control settings. Sure it’s a little dark and weak at low Fuzz settings, but the Tone control has just enough bite and snarl to create a funky and useable tone. And speaking of the Tone control, it’s great throughout the range. It feels close to neutral at noon and generates a full frequency response that is great for classic rock riffs. As you increase the control it cuts some lows and boosts highs and mids added the perfectly amount of pick attack and grit. It never gets shrill. And with high tone control settings, you can roll off the volume on your guitar and get clean(ish) without too much loss of highs. Rolled below noon, the tones get dark and muted. And it’s here where you can create some of those weird intermodulation distortions that make Tone Benders so weird and wonderful. And don’t worry, the Holy Fuzz has plenty of output to work as a lead boost or simply punish the front end of your amp.  

Bender Gets Bent

The story of the Gate control on the Holy Fuzz is that Craighton and Robert were circuit bending (poking around the circuit on a breadboard and just experimenting with component placement) when they found the location for the Gate. No one knows whether it was genius, luck, or divine intervention, but we do know it worked. Clicking the Gate into the circuit creates a whole new pedal. Counter-clockwise settings of the Gate control create ripping Velcro tones, sputtery note decay, and cool upper octave and ring modulator artifacts—all of which can be further tweaked via pickup position, as well as guitar volume and tone controls. Moving the Gate beyond noon creates crazy sputters and flat out broken tones. My favorite setting was the following: Volume at 2:00, Tone at 11:00, Fuzz at 11:00, and Gate at 2:00. The sound reminds me a little of a Univox Super Fuzz but with the low-octaves of an MXR Blue Box, at least with the volume on my guitar fully up. As I ease off the volume, notes and chords decay into a pseudo tremolo but with weird crackles and groans. Broken tones never sounded so good.

What We Like: The Holy Fuzz offers excellent MKIII tones in a (generally) affordable package with some great crazier fuzz tones to boot.

Concerns: My only concern is that once again, Keeley is building less than 100 of these bad boys.