The Abacus music computer module brings the legendary Buchla 257 and 281 synthesizers into your Eurorack system. With its array of exponential, logarithmic and linear functions, the Abacus unlocks limitless potential for sound design and modulation.

Craft Envelopes and LFOs

Shape sound over time with the Abacus. Create envelopes up to 25 minutes in length to modulate filter sweeps, amplitude and more. Or generate LFOs as fast as 1kHz to animate your patches. The Abacus puts precision control of modulation at your fingertips.

Manipulate Incoming Signals With Ease

Feed external control voltages into the Abacus to amplify, attenuate, integrate or invert. Add lag, slew or portamento effects to incoming CVs from your sequencer or keyboard. With the Abacus, you can warp and mutate modulation sources for totally unique effects.

Combine Multiple Control Voltages for Intricate Modulations

The Abacus lets you blend up to four CVs together. Mix and match LFOs, envelopes and external signals to design incredibly nuanced, complex modulations. Create slowly evolving textures or rhythmic, pulsing movement to bring your sounds to life.

Built to Integrate Into Any Eurorack Modular Synth System

Designed for Eurorack, the Abacus module fits seamlessly into your existing setup. Just connect the power cables and mount it in your case. Add the Abacus to your VCOs, VCFs and VCAs for advanced modulation possibilities. Unlock new dimensions of sound with this Buchla-inspired module.