The Lester G from Electro-Harmonix is a pedal that emulates the classic sound of a rotary speaker in a compact stompbox enclosure. It features true stereo 1/4" output jacks, an independent compressor, a tube-emulated overdrive section, and three different modes: Slow, Fast, and Break.
Fast mode gives you that twirling tremolo sound, while Slow mode provides a chorale effect. Quickly tap on the Speed/Break footswitch to alternate between the two, with the rate of change determined by the pedal's acceleration knob. However, hold down the Speed/Break footswitch, and you'll halt either setting, thereby setting off Break mode—that welcome relief-from-tension trick often used by Hammond organ players when they're holding down sustained chords. In any mode, a balance knob allows you to blend the lows of the emulated rotor with the highs of the simulated horn, effectively offering you the choice between darker and brighter timbres.