The Buchla 267e combines both a Dual Uncertainty Source / Random Voltage Generator with a superb Two Channel Filter into single module.

Random voltages are one of the key elements of any West Coast synthesizer patch, designed to add non-linear random changes to your sequenced phrases and provide an unending source of “happy accidents”, the 267e packs two random voltage generators, which Buchla refer to as Uncertainty Sources.

The Uncertainty Sources provide three different types of noise outputs and two random voltage generators, with a variable bandwidth between 0.05Hz to 50hZ allowing for changes that are super slow and evolving to drastic audio rate modulation.

External CV and pulses can be applied to the inputs, pulses let the module produce stored random voltages in time with your sequence, and applying CV to the inputs let’s you modify the mixed output and the probability change rates for semi-control random and interesting results.

The second part of the module is a dual bandpass filter, with a super wide frequency sweep, a sweet resonance range with a vast array of harmonic sweet sports. Each filter features three modulation type, which are selectable using the green push button, the three models are amplitude, frequency and bandwidth, which each provides very different modulation flavours and results.

One thing to note is that the flat noise is normalled to the signal inputs of the filter sections, so it can be used for adding filtered noise effects to your patches should you wish.

The 267e puts two circuits into a single modules space that are crucial to any patch you might create, and since the 267 is preset compatible you can store and recall any of the modules settings on the fly using a preset manager.

The main features of the Buchla 267e Uncertainty Source / Dual Filter Module include

Dual function 200e module

Provides two random voltage generators

Two Band pass filters with three modulation states

Preset storage compatible