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

Buchla 291 Dual Voltage Controlled Filter

This is the first module towards a Buchla 200 clone: The Buchla 291 dual voltage controlled filter. Using Mark Verbos’ PCB design (scroll down to “Buchla Bandpass Filter”) I made some minor adjustments and etched the PCB.

Buchla 291 - PCB based on design of Mark Verbos

After soldering the PCB I started designing the front panel in Front Panel Designer using a picture of the original front panel for reference.

Buchla 291 - Designing the front panel

I’m using 16mm Alpha pots for the front panel, banana jacks and 3.5 mm jacks. I had the basic layout pretty fast but tweaking until everything was right took a bit longer. To be absolutely sure everything would fit I decided to make a prototype front panel using scrap wood so I could see if everything would fit like I thought it would. I printed the design and drilled the wooden panel.

Buchla 291 - PCB and front panel prototype

Then I mounted the front panel components. The 3.5 mm audio jacks didn’t fit as the wood I used had a thickness of 5 mm and the jacks can only be mounted on panel with a maximum thickness of 2 mm.

Buchla 291 - Front panel prototype

And everything fits! Time to order a professionally silk screened front panel.

Buchla 291 - assembled prototype

To be continued…


5 responses to “Buchla 291 Dual Voltage Controlled Filter”

  1. Any chance for an FPD file for this filter?

  2. Hi,

    Where did you get that blue PCB?


      1. Gábor Kakuk avatar
        Gábor Kakuk

        Hi Andre,

        Thanks for the tip.
        Is it possible to contact you somhow?
        I’ve ordered this from Conrad Hungary, actually 2 times, but I’ve got the simple, natural brown version.
        I need at least one piece to finish my 112 clone 🙁

        1. Hi Gábor,

          Sorry to hear you’re getting the wrong PCB’s from Conrad. Unfortunately I do not have any blue PCBs left but I will have a look if I still have the original invoice to check the product number.
          If you want to e-mail me, use the e-mail address on the About Me page…