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Halo (Legacy)

Based On
EHX® Big Muff Pi
Effect Type
Distortion / Sustainer, Fuzz
Build Difficulty
Project Summary
One of the most classic guitar effects of all time, its sound falls somewhere between a distortion effect and a fuzz with an incredibly long sustain.

Legacy PCB

Designed for the 1590B enclosure with side-mounted jacks, which some builders prefer. Bypass PCB (optional) sold separately.


In stock

Updated Version

The same circuit, but updated for the 125B enclosure format for a more streamlined build. The bypass switch PCB is integrated.


In stock

Project overview

There’s no shortage of PCB offerings for a Big Muff, but I’ve tried to make a board that could be used to build any variation or clone out there as well as incorporating a number of mod options. Here are a few of the features:

  • Optional “Presence” or midrange control (more info at AMZ). If you choose not to use this control, the Tone pot has two possible orientations so you can still have a symmetrical control layout.
  • Extra pads for clipping diodes, allowing you to easily use LEDs or just about anything else
  • Choice between two different gain recovery/output stages: “classic” or JFET (like in the BJFE Fire Red Fuzz)
  • Space for large 1uf film caps where appropriate, allowing you to build any historical variant of the BMP