The Jen KPS-900 Phase Shifter is a vintage guitar pedal known for its unique, swirling phasing effect. Unlike other phase shifters of its time, the KPS-900 uses a CD4007 chip instead of JFETs, eliminating the need for transistor matching. This design choice makes the pedal more accessible and easier to build.

The pedal’s tone is often described as having a “Hendrix/Gilmour/Uni-Vibe-like” quality, with a distinctive “swirling” effect. The Jen KPS-900 Phase Shifter has gained a cult following among guitarists and pedal enthusiasts, with many seeking out original units or attempting to build their own versions based on available schematics.

KPS 900 Phase Shifter