DIY Audio Projects – Designing….

I’ve been working on some DIY audio projects for some time now that are finally far enough down the line, that I wanted to share them.

One of the more interesting projects ( and difficult…. ) is restoring some old designs, like the Moog Minimoog Model D circuits, from scratch, using new and readily available parts, yet still keeping as close as possible to all of the aspects of the original designs that made it sound “good”.

Luckily I have a very clever and resourceful friend ( whom also happens to be a brilliant photographer: talsit ) who is currently doing a lot of this DIY type stuff, and hence, I have a lot of very good help.

The first piece of work I had to do was source the original circuit diagrams, which I found here: fantasyjackpalance

Next, I had to source the parts, or, at least, extremely appropriate equivalents, which I’ve managed to do with the following supplier ( whom are also incidentally Australian, which is quite useful since I live in Sydney 😉 ): element14

Then I used LTSpice to simulate these circuits, and make any necessary improvements to them including accounting for changing the component types, or fixing poor performance based on circuit measurements.  Here is a screenshot of the VCF ( voltage controlled filter ) design I’ve been recently adapting to build ( quite a few of you will notice the unmistakable topology of this circuit, and notice it’s a Low Pass 24dB transistor ladder filter from the Minimoog Model D ) along with a simulation that exercises a bunch of different resonance values:

From there a transpose this schematic into Eagle:

Then from there I piece together a board layout for the parts:

And the next step is to actually build these projects.

Stay tuned, more to come soon….

3 thoughts on “DIY Audio Projects – Designing….”

  1. Hi there I know you did the eagle mini moog vcf a long time ago but it’d be so cool if I could get the eagle file to mess with.

    I have a synth blog and if I came up with something useful from the files would give you a shout out.


  2. Can I please get a copy of your eagle files for the mini mood d filter, I’d love to mess around with it. Specifically I am trying to incorporate a that array for the ladder.

    1. Hi Charlie,

      I’m not releasing any of my Eagle files because they are:
      a.) untested and
      b.) they’ve taken me countless hours to make
      and I’m not yet ready to give them away for free considering how much time they took me to make.

      Happy to help you make your own, however.

      What issue are you having with yours?

      Thanks for the interest!

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