I have build my first synthesizer end off the 70’s out of a kit which was based on the schematics from Elektor, a German DIY electronics magazine. This synthesizer was called “Elektor Formant”. This was way before the Internet gave us access to so many resources. Nearly everything has to be ordered via mail order. Or bought in shops if you was lucky enough to life nearby. The only resources then were some magazines or rare books. While life went on the building stopped. The synthesizer was stored away in a closet.
Some five years ago I started to restore my original Elektor Formant and got it working. Over the last years I build a lot of more modules from other sources first on strip-board and now on PCB. Mostly my own designs inspired by many fellow SDIY builders. I have done some bigger projects like Shakuhachi to Synthesizer which enables the Shakuhachi player to steer the synthesizer from the flute, or a 24 Band Vocoder.