The WoollyTron is our take on the zVex Mastotron

A heavy silicon fuzz and a variation of the zVex Woolly Mammoth. It can produce a wide sonic range from 8-bit sounds to complete wall-of-fuzz tones. There's alot of variation in the box of fuzz and you can dial in some very subtle...and very extreme fuzz!


  • RELAX/PUSH: introduces source impedance to the signal going into the circuit. When fully up, the signal goes in raw... when turned down, source impedance is added as needed to “soften” the input for active pickups.
  • FUZZ: This wide-range knob lets you set just how fuzzy your board gets.
  • PW: Pulse Width control. You can swing this from square wave on the left to narrow pulses on the right.
  • TONE: This shapes the treble without sacrificing the heavy subs.
  • VOL: Output volume.
  • SUBS Toggle: Lets you set how much sub content is in your fuzz. It’s pretty dramatic... huge, medium, and absolutely none. Try 1 with the tone turned down!

Note: Remember to socket any IC's and transistors.

Compares to: zVex Mastotron

Additional information

General Build Guide Five Cats Pedals - General Build Guide V1.1
Compares to zVex Mastotron
Build Docs WoollyTron – V1.0 – Build Docs
Interactive B.O.M WoollyTron – Interactive B.O.M (.zip download)
Schematic WoollyTron - V1.0 - Schematic
Transistor Finder
Mega Packs from Five Cats Pedals