FX20 Phasor

Two original-issue FX20s,
from 1982 (left, with 'foam' treadle) and 1984

The FX20 Phasor was one of the original ten DOD FX-series pedals that debuted in 1982, essentially replacing the Phasor 490 in DOD's product line. Like the 490, the FX20 was a four-stage phasor with four OTA chips, while the FX20 also featured additional circuitry to support silent FET switching. Compared to other phase shifters, the FX20's circuit was more closely related to the Electro-Harmonix Small Stone, which used 3080 OTA chips, rather than the MXR Phase 90 or the Boss PH-1, both of which used FET resistance to vary the phase. The FX20 remained in production until mid-1985, when it was replaced by the FX20B (which featured a six-stage regenerative phase circuit).

home * FX index * America's pedal? * field guide * serial no. info * FX literature
what's new? * FX tech info * links *disclaimer/legal/contact us