Turn your OP-1 Portable Synthesiser into a hand-cranked music box with the Crank Accessory from Teenage Engineering . Just mount it to the synthesiser’s blue knob and press Shift + Rec to activate the hand-crank recording (crank LFO) mode. You can now control the LFO speed with your hand to create a real vintage old-skool sound.
This accessory lets you tweak almost any parameter and crank the notes clockwise or counterclockwise (reverse recording) in real time. In addition, it can also be used with the Endless and Tombola sequencers.