Under the label kassutronics I create original circuits for modular musical synthesizers and other do-it-yourself sound electronics projects. Some of these are available for sale as printed circuit boards and face plates, others are only circuits or instructions.
All information, instructions, circuits and detailed explanations can be found on my blog, kassu2000.blogspot.com. This repository contains build documentation for modules that are for sale, and some smaller projects/workshops that are available as open source material.