Reckless Vibe

An original vibe pedal: four all-pass phase stages and a sinusoidal low-frequency oscillator, all built on transconductance amplifiers.

The vibe has long been a favourite effect here. After owning several vibe pedals, from the Uni-Vibe reissues to the Rotovibe, and building the Tri-Vibe from runoffgroove, the next step was to design one from scratch.

The circuit. Four all-pass phase stages built on LM13700 transconductance amplifiers. The LFO is OTA-based too: a true sinusoidal quadrature oscillator, whose speed is set through a BJT exponential converter. A blend control sets the mix of dry and shifted signal. Pre-emphasis and de-emphasis around the OTA stages keep their hiss down, an idea credited to runoffgroove's Tri-Vibe. Getting the OTA quadrature oscillator to behave took a lot of tweaking.

The first build, in 2017, fitted a 1590DD enclosure. Revision E brought a smaller PCB and an expression-pedal input for controlling the speed with your foot.