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, April 28, 2017

Hornby Skewes Zonk Machine

The Zonk Machine was one of the many British fuzz boxes that came out in the mid-60s. Like the Tone Bender Mk II it was designed to compete with, it also was featured 3 germanium transistors but offered more of a boost and slight oscillation (in a good way). This is a positive ground effect so unless you use a charge pump or can make it work with NPN germanium transistors you can't daisy chain it with other negative ground pedals. If you are going the NPN route, be sure to rotate the polarized caps an the diode 180º. Here's the schematic for reference.


  1. I etched fuzz centrals zonk machine and changed 3 components to make a mark 1 tone

  2. verified today! I used pot b500k like a bias instead 470k from base Q2. Q2 should have 100 - 150 hfe. I tried silicon Q2 with 160,220,800 hfe, they all working bad. So i used all germanium mp38a. Similar to demo!

  3. today i found old this is PCB, & built Bender MK1. All PNP soviet:Q1-mp42b hfe=60, Q2-mp39 Hfe- 130, Q2-Mp20b Hfe-115. Scheme: