I wanted to learn about the theory of vocoders so what better idea to build one by my own?
This is actually quite a reproduction of the vocoder published in 1980 in the German Elektor magazine. They worked at that time very close together with ETI and it seemed more interesting to me that the Elrad or Paia DIY projects.
I have actually redrawn all the PCB layouts as the originals were nowhere to find as a good scan.
Here’s a link to the French version of the original Elektor Vocoder article, I did not find a German or English version but since my French is pretty good, this really did not matter.
Another link to a dedicated Elektor Vocoder site, this time in German.
I also built the voiced-unvoiced detector which Elektor added somewhat later in an addendum article to the vocoder.
I personally think that the intelligibility is pretty good and quite accurate but it is also depending on the carrier signal you feed in. Compared to a Roland VP330 Vocoder plus, the Roland seems much creamier and smoother, the Elektor more analytical.
One day when I find a bit of time I will redo the frontpanel graphics which I made with clear self adhesive dymo prints and change them against some Lazertran printed decals which will probably look better.
Sound examples yet to be added