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DIY Modular Synth

I am building a modular synthesizer for DAW-less music live performances. The following pages document the progress.

Sub-Projects

This project consists of multiple sub-projects. Each sub-project's documentation can be found below.

Idea & Requirements

The main requirement for the project is that it is robust, easily and quickly to (re-)build, and low-cost. Whichever visual or sonic aesthetic results from these requirements will be considered an intended aspect of the project.

A design that fulfills the given requirements is where the modules are fabricated as one-sided PCBs using subtraction milling with SMD parts only. By avoiding THT parts, the fabrication process is more time efficient and the PCB (which is then flat on the back) can easily be mounted onto something else. Because I plan to grab the modules often for moving them around, I will probably screw the PCBs onto pieces of squared timber. These blocks would then be mounted onto some flat surface (e.g. the bottom of a flight case) using velcro tape or neodymium magnets.

The power and signal format will be those of the Eurorack standard. I assume it is easier to debug if one follows the V/Oct format. Furthermore, there are plenty of DIY designs already to be found that follow the Eurorack format already. It will be easier to adapt them when following the same format.

How to Read This Documentation

You can start reading anywhere in the series of sub-pages. If you find that there is some information missing (e.g. I am using some unusual footprint, some special design pattern etc.), I introduced that information on an earlier sub-page. In that case, please check there. In any case, all design files including the footprints used are available for download at the bottom of each page. This will lead to a more cleaner documentation without redundancy. I would like to avoid redundancy unless it is really necessary, since it could introduce inconsistency in the documentation. The pages are ordered chronologically.

PCB Design & Tools

General Design Patterns & Rules

Output buffer:

buffer (to de-couple current) -> voltage divider (scaling down output) -> 1k resistor to limit current in case of short (necessary if a poti is used in the voltage divider)`

Eurorack electrical standards