The Halo Deluxe Distortion/Sustainer is based on the Cornish P-1, an adaptation of the EHX Big Muff Pi V2 (Ram’s Head) with two transistor buffers added to the front of the circuit to reduce noise and improve the signal isolation.
The P-1 started life as a circuit called the “Custom Fuzz” designed for David Gilmour in 1976 as part of his integrated pedalboard. It was a part-for-part clone of Gilmour’s favorite Big Muff with high-quality transistor buffers added. It was known as the Custom Fuzz all the way up until 2006, when it was renamed to the P-1 to better indicate its relationship to the P-2.
The P-2 (and its sister circuit, the G-2) are also largely Big Muff clones, but the major difference is the tone control. The original BMP bass/treble panning control is responsible for its signature mid-scoop. The P-2 and G-2 replace this control with a standard treble-cut control, which significantly changes the voicing. The P-1 leaves the tone section intact.
Broadly speaking, the Halo Deluxe is a hybrid of our Cygnus and Halo projects. The core circuit is a standard Big Muff, to which we’ve added the Cornish buffers and the true bypass slide switch. The Halo Deluxe also includes the midrange switch from the original Halo. We have kept the part numbering the same for the core circuit, so you can use our spreadsheet to build a Cornish-buffered deluxe version of your favorite Big Muff.