Drawmer OC-1 500 Series Optical Compressor

The Drawmer OC-1 is a fully featured optical compressor designed to bring rack-mount precision and character into the 500 series format. Its optical gain cell delivers soft-knee feedback compression with a smooth, programme-dependent response that maintains transparency while adding warmth and cohesion. Uncommon for a single-slot module, the OC-1 provides 21-position precision detented controls across all parameters including threshold, ratio, attack, release, input and output gain, plus wet/dry mix for parallel compression. Comprehensive metering displays gain reduction and switchable input or output levels on the VU meter, while hard-wire bypass ensures completely transparent signal routing when disengaged.

The BIG and AIR modes, borrowed from Drawmer's acclaimed 1973 compressor, reshape the sidechain's frequency response to preserve low-end punch and high-frequency detail. BIG reduces sidechain sensitivity to bass content, preventing unwanted pumping from dominant low frequencies. AIR preserves top-end clarity that compression typically dulls, maintaining articulation on vocals and natural sparkle on acoustic sources. PGM mode introduces adaptive release behaviour, engaging a second slower release time that responds to programme material above threshold to reduce artifacts during heavy gain reduction. The CRUSH saturation circuit adds harmonic richness that varies with input level, thickening low end and adding midrange presence. Stereo linking via pin 6 of the 500 series chassis synchronises threshold, ratio, BIG, AIR and gain reduction metering across adjacent modules.

Features

• Optical soft-knee feedback compression with smooth programme-dependent response
• 21-position detented controls for threshold, ratio, attack, release and gain
• BIG mode reduces sidechain low-frequency sensitivity to preserve bass energy
• AIR mode maintains high-frequency detail and transparency during compression
• PGM mode adds adaptive slower release to reduce pumping artifacts
• CRUSH harmonic saturation circuit for analogue warmth and tonal richness
• Wet/Dry mix control enables parallel compression within the module
• Stereo linking via 500 series pin 6 for multi-channel operation