Sunday, April 7, 2013


I guess it was only a matter of time before someone (in this case,  Robbie McDonald) translated Don Buchla's elegantly screwy electrical ode to unpredictability to the Eurorack format.  Its design is exactly the same as Buchla's,  but of course eighth inch cable inputs/outputs are featured throughout (no bananas).    I could certainly use an explanation here,  but in the randomness sweepstakes why not throw caution to the wind? For those who cherish chance,  the West Coast Random Source is available at Brooklyn's very dependable brick and mortar modular synth outlet,  CONTROL.

A clarification from Robbie McDonald:

The module is a 100% clone of the original Buchla 200 series,  266 Source of Uncertainty.

The schematics, sans the obsolete parts, were put to pcb in eurorack format by fellow wiggler Roman Filippov. Roman did all of the hard work, I just built the module from the pcbs he created. I had two of them,  but felt that I only needed one. 
With that being said, Don never created a users manual for the 266 but those two sections are pretty straight forward.

The Integrator is a simple Glide/Portamento circuit. You run cv into it and it smooths out the variations in the signal. 

The sample and hold grabs the voltage of a continuously varying signal and holds (locks, freezes) its value at a constant level until the next pulse arrives. Once the pulse arrives the varying signal is again locked into place. 
For the S&H run a pulse or gate into the "pulse in", put a envelope generator or one of the "fluctuating random voltages" into the "c.v. in", and run the c.v. out into 1v/oct of an oscillator. Boom, hours of stepped randomness! 


  1. This looks like a straight up clone of the Buchla 266. I don't think that this goes any further than that.

  2. Many thanks to both of you for your responses to my post.

  3. i would like to have one too. where could i get the pcb's, components, faceplate and stuff?
    will it be available as a kit?
    dou you plan to clone other buchla modules?
    i would be interested in buying diy kits.