This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Friday, November 20, 2015

MicTester's 1969 Fuzz Box

Her's a unique fuzz circuit from MicTester for your #FuzzFriday. Here's what he had to say about it:

Way back in 1969, I heard "Inna Gadda Da Vida" for the first time. I realized quickly after building some simple transistor stages that didn't work properly that "the" sound was coming from abused transistors! Experimentation over some weeks led to [this circuit]! Just two pots give an amazing range of distorted sounds and none of the components are critical. 

Please tweak away until you find the sound you want! Alter capacitors, change the transistors–experiment!

The original FSB thread with the schematic can be found here.


  1. To give an actual build report:

    The fuzz is buzzy and a little on the thin side. The Fuzz knob is more like a gate control than a regular gain knob. Except for a volume drop at the extreme counter-clockwise end, the volume and distortion don't change too much, making it easy to dial in how much gating you want.

    On the FSB thread, Nocentelli posted a modded version with 100nF coupling caps, a reworked volume control and a Fuzz Face-style gain control for Q2. I did try clipping in a 2k pot and a 22uF cap in series from Q2's emitter to ground. The gain control let me push the fuzz into more extreme territory, but doing this caused a low-level squeal until I dialed in the appropriate amount of gating. Turning up the gain also really brought out a percussive, scrape-y sound to the pick attack. I prefer the simplicity and ease of use of the original circuit, but the gain mod is worth trying.