The SynthCard Project

Open Guidelines for SynthCard Design

NOTICE: This is still a working document. If you’d like to contribute to the development of this document, let Benjie know through Instagram @benjiaomodular or through the project’s Github.

This document serves as a guide for everyone making SynthCards. The spirit of this document is to allow SynthCards designed by different makers to work with each other.


SynthCards must be standard business card sized 3.5" x 2.0" or 8.9 x 5.1cm. Cards can optionally have rounded corners. No restrictions on card thickness for now.



Power input for SynthCards should be between 5-9V.

Power and ground outputs should be available in the form of 2.54-pitch pin connectors to allow chaining of multiple boards together. This will allow people to chain multiple SynthCards together.

Make sure to clearly label the voltages used by your card!


Power connections should be done using 2.54-pitch pin headers. An extra pair of power connectors should be available to allow chaining of multiple cards together.

Audio and CV connections should be available through 2.54-pitch pins. SynthCards should be patchable using Dupont connectors.

The addition of 3.5mm jacks is optional to allow operability with standard Eurorack systems. 2.54-pitch pins should still be available regardles of having 3.5mm jacks.

The builder will have the freedom to use either pin-headers or pin-sockets on the connectors.