I make films, photographs and electronic music. I build electronic musical instruments

Mutant 259 timbre / modulation index

Mutant 259 timbre/modulation index PCB v06I’ve been working a while on the timbre section of the Buchla 259 and this week I spent a couple of evenings finishing the PCB design. This is how it looks now.

The PCB is the same size as the 258J oscillator and the power connectors are on the same location which makes for easy power wiring when stacking the PCBs.

The board contains the 259 timbre section and two 292C VCAs that function as  modulation index section. An additional TL074 configured as 4 non-inverting opamps were also added.

Together with two 258J oscillators I’m planning on building a “mutant complex waveform generator” with it, inspired by the Buchla 259 complex waveform generator. The block diagram is shown below.

Mutant Complex Waveform Generator - block diagramThe signal from the modulation oscillator is fed into the modulation index where you can select the modulation destinations. Timbre can be modulated and the principal oscillator can be FM or AM modulated.

This should provide some very interesting and varied sonic possibilities.



4 responses to “Mutant 259 timbre / modulation index”

  1. Hi. First of all, good job! If everything sounds as godd as it looks… .Is there any chance you publish this mutant 259 PCB? Is it for sale somewhere?.
    Thanks, and please keep up your good work.

  2. Hi Nicolas,

    Yes, the PCB will be for sale when it’s finished and tested. I will post more info in the DIY Music Tech forum on Muffwiggler when it’s ready.

  3. Benjamin O'Mahoney avatar
    Benjamin O’Mahoney


    Wow, amazing work on all the Buchlaesque designs. Please put me down for some PCBs. I am following at Muffwigglers… Will you include complete 258/259 mutant design? I saw your 258ish pcb said Mutant.. Can’t wait to hear more!

    1. Hi Benjamin,

      My PCB will contain the mutant timbre section, 2 VCA’s and a modulation index which enables you to route signals in certain ways. The VCO’s I plan to use with this PCB are two 258j VCOs but you can use any VCO you want.

      More info soon as I expect the new prototype PCB next week…

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