Keeley Electronics Bubble Tron Dynamic Flanger Phaser

$199, robertkeeley.com

The Bubble Tron combines several “vintage effect classics that never were” in one stompbox. Inspired by the sounds of Frank Zappa, the pedal packs filter, sample and hold, dyna flange and dyna phase effects, accessed via three modes: filter, phase and flange. The dynamic flanger and phaser respond to pick attack, which starts and stops the effect; the phaser also offers a more typical LFO-based swirl. Kicking in the filter, meanwhile, engages keyboard-like sounds and allows players to control its different ramps or set it to a more random nature using shape and sensitivity knobs.