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Cepheus Amp Overdrive

Based On
Cornish CC-1/GC-1
Effect Type
Build Difficulty
Project Summary
An original design by the legendary Pete Cornish featuring two soft-clipping stages followed by a 3-band EQ for a natural and tweakable crunchy overdriven tone.
Cepheus Amp Overdrive printed circuit board

Printed Circuit Board

What's included?
PCB only. Build instructions and parts list can be viewed or downloaded from this page.


In stock

Complete Kit

Not yet available.
Kits are developed based on interest, so if you’d like to see one for this project, let us know.
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Project overview

The Cepheus Amp Overdrive is adapted from the Pete Cornish CC-1, traced by Aion FX in 2020, and the GC-1 which we traced in 2023. The GC-1 claimed to be an original circuit, but we found it to be identical to the CC-1 other than changes in component values.

Cornish pedals are best known for being extremely expensive. There are two reasons for this. First, the build quality and reliability is unmatched. Second, the mysterious nature of them, partially due to the fact that the circuit is obscured and partially because of the A-list of clients such as David Gilmour, Brian May and Pete Townshend.

Like the OC-1 Optical Compressor, the CC-1 is a fully original circuit that’s not based on anything else. It’s designed primarily with op-amps, beginning with two feedback clipping stages, each with resistors in series with the diodes to soften the effect. The two-stage stacked clipping gives a very amp-like feel that responds naturally to playing dynamics or increased input signal levels.

After the clipping section, there’s a three-band active tone control adapted from manufacturer application notes (see figure 7 on this page), essentially a Baxandall with an extra band for midrange. There is also a gain boost so the output level can be compensated if the tone controls are cut.

The Cepheus is a faithful reproduction of the CC-1/GC-1 circuit, but with one major addition: an internal slide switch allowing the pedal to be used in true-bypass mode instead of buffered bypass. As with the Klon KTR, the buffered mode is “almost always better”, but with this feature, you can determine for yourself.