“The Uni-Vibe was an excellent alternative to a Leslie and became a mainstay for Jimi Hendrix”: Everything you need to know about modulation, from Leslie emulators and chorus pedals to bucket-brigade chips and phasers

Boss CE-1 Chorus Ensemble.

In our recent feature on tremolo, we described how a valve can be configured to create a low-frequency oscillator (LFO) that can modulate amplitude.

You can’t actually hear the oscillator itself, merely the effect it has, and that effect isn’t restricted to tremolo. In addition to amplitude, an LFO can be used to modulate pitch, frequency response, phase and delay – and that leads us onto vibrato, chorus, flangers and phasers.