The Protolith CMOS Distortion is a guitar pedal that is based on the Mad Professor Stone Grey Distortion circuit. The Stone Grey Distortion was originally derived from a distortion circuit called the “CMOS Driver” from a Japanese electronics book published in the 1980s. The circuit has been tweaked and modified over the years, but the final Stone Grey circuit still strongly resembles the CMOS Driver.

The Protolith retains the same circuit as the Stone Grey Distortion without any modifications or changes. It uses cascaded CMOS stages alongside traditional diode clipping to achieve its high-gain drive sound. The pedal has a significant amount of low cut, which gives it a tight and focused tone when used with certain types of amps and playing styles.

However, some players may find the Stone Grey Distortion to be too thin sounding. To address this, Mad Professor released the Custom Shop “Modernized Mod” in 2020. This modification adds 3 parallel parts on the solder side of the PCB to increase bass frequencies and gain, making the pedal more suitable for players who prefer a fuller sound.

The Protolith, being based on the original Stone Grey Distortion circuit, does not include the Modernized Mod. It is a faithful reproduction of the high-gain drive circuit designed by Bjorn Juhl and first released in 2011.

Summary created by AI from the original source.