The 1978 redesign of the classic Big Muff, known as the “op-amp” EHX Big Muff Pi, was a significant departure from the original transistor-based circuit. Designed by Howard Davis, it aimed to achieve a similar sound to the Big Muff but utilized op-amps instead of transistor gain stages.

The Corvus Distortion / Sustainer is a clone of the 1977-1980 op-amp Big Muff Pi circuit. It was designed to replicate the sound of this version of the Big Muff, but it should be noted that the circuit itself is quite different from the earlier transistor-based version, apart from the tone control.

Originally, the Corvus was the only commercially-available version of the Big Muff for several years, and it was seen as a separate circuit due to its differences from the original. However, in 2017, Electro-Harmonix reissued this version of the Big Muff and officially named it the “Op-Amp Big Muff Pi.”

The Corvus is specifically based on the 1978 revision of the op-amp Big Muff, which introduced a “Tone Bypass” switch. This switch allows the tone stack to be fully bypassed, resulting in a more raw and aggressive sound.

The Corvus closely follows the 1978 circuit, with the addition of an optional modification to the gain control. This modification, conceived by Analogguru, converts the op-amp configuration into a variable gain stage. In the stock unit, the op-amp provides a fixed gain boost followed by a volume control. With the modification, the op-amp only amplifies the signal as much as necessary. However, the original version without the modification can also be built if desired.

Overall, the Corvus Distortion / Sustainer is a faithful adaptation of the 1978 op-amp Big Muff Pi circuit, with the option for a gain control modification for added versatility.

Summary created by AI from the original source.