Fulltone OCD V2

Fulltone OCD V2

From Wikipedia:

The Fulltone OCD
In 2004, Fulltone released the Obsessive Compulsive Drive (OCD), a hard-clipping, op amp-based overdrive that took design cues from both the Tube Screamer-based Voodoo Labs Overdrive and the MXR Distortion+, with an “open” sound and enough headroom to mimmick a driven tube amp.[56] Dubbed by Music Radar a “game-changing” design, the OCD further established Fulltone’s prominence in the boutique market while gaining fans like Billy Gibbons, Paul Gilbert, Eric Johnson, Peter Frampton, and Don Felder.[56][57]

The OCD has gone through multiple iterations, with changes from versions 1.1 to 1.7 being generally subtle alterations of the pedal’s EQ response. Version 2 brought more noticeable changes, with a new output buffer and JFET transistor input stage, and the option to use a new type of switching, enhanced bypass, instead of true bypass.[57] After the first iteration, the drive pot’s value was also increased for a more “dramatic” distortion, while an asymmetric germanium diode was later added to shift the character of the clipping.[57] All versions of the OCD feature an HP/LP toggle switch, which stands for “high-peak/low-peak” but is often incorrectly thought to mean “high-pass/low-pass.”[57] HP mode adds distortion and presence, as well as a more pointed midrange, while LP mode maintains the amp’s character.[58]