TipTop Audio

Buchla Model 266t Source Of Uncertainty


TipTop Audio has teamed up with Buchla to revive Don Buchla’s classic 200 series modules, converting them into Eurorack format.

The Buchla Model 266t provides a general source of musical unpredictability


  • Quantized Random Voltage:
  • - Pulse Input activates a random stepped voltage at the Output
  • - The knob osets the varying number of steps from setting 1 to setting 6
  • - CV Input controls the number of steps
  • - n+1 is more locally scaled in the 5V range
  • - 2^n is more equally distributed over a 10V range
  • Stored Random Voltage:
  • - Pulse Input activates a random stepped voltage at the CV Outputs
  • - The left CV Output is an evenly distributed random voltage
  • - The right CV Output has a potentiometer and CV input to determine the random voltage distribution.
  • - CV In affects the “curve” distribution of the right CV Output
  • - The knob osets the “curve” distribution of the right CV Output.
  • Fully counterclockwise skews in favor of lower voltages. The middle is a bell curve distribution and clockwise skews toward higher voltages.
  • Fluctuating Random Voltages:
  • - CV Input controls the probable rate of random voltage change
  • - Knob osets the probable rate change from slow 0.05hz to 50hz
  • - CV Output of voltages with LED indicating the fluctuation rate
  • Integrator:
  • - Input is looking for discrete or stepped voltages
  • - The knob proportionally smooths out the incoming voltage from 0.01 (no smoothing) to 10 (dramatic smoothing, glissandi)
  • - CV Input controls the smoothing potentiometer
  • - TR1 is a trimmer on the back of the module, it adjust the range of the Integrator
  • Sample and Hold:
  • - Pulse Input samples the voltage at the CV Input
  • - Pulse “alt” divides the incoming pulse into alternating pulse outputs
  • - CV Input for periodic, continuous or fluctuating voltages
  • - CV Output of the complete voltages
  • - CV Output “alt” divides the voltages into alternating outputs (great for ping pong effects)


  • Width: 24 HP
  • Depth: 25mm
  • Power: +12V 150mA / -12V 100mA