PCB structure

The complete Moduleur system consists of 18 PCBs:

• Module PCBs (8x2) — Each module is built up of two PCBs: a Core and a UI board that are connected through pin headers and sockets
• PSU PCB — The power supply unit (PSU) board supplies +/-12V to the modules
• Default patch PCB — The optional passive board called "Default patch" pre-patches modules inside the synth — essentially making the Moduleur semi-modular

Power

There are two PSU PCB designs available in the design files. Both boards use the same base design, the difference is in the number of connector and the pin headers.

PSU for the Moduleur enclosure

A special PSU board with 4 power connectors, designed for the Moduleur enclosure. Uses right angle 16 pin headers that welcomes Eurorack cables. To power the 8 modules of the Moduleur you'll need Eurorack cables with an extra floating pin socket on each cable. You can easily make these cables, here's how.

Eurorack PSU board

Use this if you plan to use the modules in your own case.

Modules

Each module are split into two physical PCBs:

1. A Core PCB
2. And a UI PCB

Core PCB

The Core PCB contains the core functions of a module:

• audio path
• control voltages
• digital logic (if applicable)
• power conditioning and protection

The Core PCB defines how the module works electrically.

UI PCB

The UI PCB contains the user interface components:

• potentiometers
• buttons
• LEDs
• jacks

The UI PCB connects to the Core PCB and translates user interaction into electrical control signals.

This separation:

• keeps complex circuits compact and clean
• simplifies mechanical layout and panel design
• allows UI changes without redesigning the core circuit

The two boards connect to each other through pin headers and sockets, and using spacers and screws.

Default patch

In addition to the individual modules, the Moduleur includes a default patch PCB.

The default patch PCB internally connects selected module inputs and outputs to form a usable signal path without any patch cables. This allows the Moduleur to function as a pre-patched, semi-modular synthesizer out of the box.

The default patch:

• provides a sensible starting configuration
• does not prevent external patching
• can be overridden or ignored entirely

Default patch signal flow

Inserting a patch cable in any of the jacks breaks the default connection which makes the system behave like a fully modular synthesizer. Without them, it behaves like a pre-wired instrument.

Complete PCB stack

Here's the physical board stack setup:

• The UI board is mechanically connected to the Moduleur frontplate or a Eurorack panel via M3x10mm threaded spacers and M3 screws
• The Core board is electrically connected to the UI board via pin headers and sockets. It doesn't matter if you use headers on the Core board and sockets on the UI board or vice-versa.
• The Core board is mechanically connected to the UI board via M3x12mm threaded spacers and M3 screws
• The Default patch board is electrically connected to the UI board through long pin headers (on the default patch board) and regular pin sockets (on the UI board).

The default patch PCB can be omitted or ignored if the module is used in a fully modular configuration.

Make sure to mix and match male/male and female/male spacers.

Electrical connections between the boards are made exclusively through the pin header/socket interfaces shown in the diagram.