HaloDistortion / Sustainer

From the vendor

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.

The Halo Distortion/Sustainer is a recreation of the Electro-Harmonix Big Muff Pi, first released in 1969. Originally marketed as a “harmonic distortion sustain”, it has been lumped together with fuzz effects, although it’s a very different animal than classic fuzz effects like a Fuzz Face or a Tone Bender.

While the overall circuit has barely changed in 50+ years, Electro-Harmonix was notorious for changing the part values on a whim without advertising the new versions as being different than previous ones. There are around 20 notable variants and many more minor variations within those, with nearly every part in the circuit being tweaked at some point or another.

The Big Muff is a very easy build and there aren’t a lot of things that can be messed up. The transistors don’t need to be biased or sorted by gain, and there are no rare or specialized parts. It’s endlessly tweakable, and you can replicate dozens of different variants by substituting a few parts. For this reason, it’s one of the most popular builds in the DIY community, and has become something of a rite of passage for those getting into the hobby. It’s also a great way to experiment and learn how simple audio circuits work because almost any part substitution will have an audible effect.

The Halo project is a faithful recreation of the Big Muff, allowing any standard variant to be built. The kit is available in the four most popular versions: Triangle, Violet Ram’s Head, Gilmour, and Civil War. Each of these is described in the “Kit Variants” section below, or on page 10 of the kit build document.

If you’re sourcing your own parts, we created a versions spreadsheet that compiles all the notable variants so you can easily see which parts to substitute for any of them.

The Halo project includes one modification to the original circuit: a midrange switch that allows for the stock mid-scoop tone, a flat midrange response, or boosted midrange. In the mid-scoop setting, it’s 100% identical to the Big Muff circuit, but the switch allows two extra modes if you find that it’s getting lost in the mix.