Quartz Optical Compressor

COMPRESSOR

EQUALIZER

The Quartz Optical Compressor is based on the Diamond CPR-1 Compressor and BCP-1 Bass Compressor, two vintage-inspired optical compressor pedals that share the same overall schematic. The original Diamond Compressor was released in 2005. Like other optical compressors, it used an optocoupler for dynamic gain reduction. But the tone control was something never seen before in a pedal: an adaptation of the “Tilt” control from the Quad Model 34 hi-fi preamps of the 1980s, which is similar in usage to the bass/treble pivot of the Big Muff tone control, but refined so that it has a truly flat frequency response in the middle. The Quartz is an adaptation of the original Diamond circuits that allows either the standard or bass version to be built. Our version also adds a third position to the frequency selector, which is a feature in the 2023 compact pedals but not the originals.