A triple envelope follower project

The 230D Triple Envelope Follower is designed to replicate the functionality of the Buchla 230A module using modern construction techniques and readily available parts. It is primarily based on the original circuit designed by Don Buchla, with the following additions/alterations: 

  • Proper current limiting implemented for pulse output LEDs, increasing LED life and preventing crosstalk between channels
  • Pulse/gate output voltages adjusted to 10V/5V
  • Pulse outputs are buffered, protecting the passive pulse generation network from the effects of loading when stacking one output to multiple destinations
  • Pulse outputs are designed to allow stacking of multiple outputs to a single input, whilst also being able to drive a floating input low.

The repository contains:

  • KiCad project files
  • Schematic and build/calibration notes as PDF files
  • Bill of Materials in ODS and PDF format
  • Interactive webpage for matching BOM items to PCB locations

The 230D is designed to be suitable for hand assembly, but it is not recommended as a “learn surface mount” starting point. You should at a minimum have a temperature controlled soldering iron with a reasonably fine point and good quality solder 0.5mm diameter or finer. Some form of magnification may be beneficial for placing and inspecting the SOT-363 packages.

Full documentation is available from https://www.github.com/DunningtonAudio/230D

Boards can be purchased here, and front panels can be purchased here.

Front side of PCB –


Rear side of PCB –


Example of populated board –


Example of completed unit –


Notes –

  • PCBs are supplied bare (other components must be sourced)
  • No warrenty is given nor implied