Tiny PSU Board for Eurorack Synth

As a modular synth enthusiast, having a stable and reliable power supply is crucial for optimal performance. But finding a power supply unit that is both compact and powerful enough to support a Eurorack synthesizer can be a challenge. In this article, I will detail my journey in designing and building a tiny switching PSU board for my Eurorack synthesizer, which packs a punch despite its small size.

Choosing the Components

When it came to selecting the components for my power supply unit, I decided to purchase the +12V, -12V, and +5V submodules from AliExpress. While building the submodules myself would have been an option, purchasing pre-built submodules saved me time and effort. I also opted for the XL6009EI for the +5V and 4A regulation (blue board), and aboard with two TPS5430 for +12V at 3A and -12V at 2A regulation (green board).


Designing the PCB

With the components selected, the next step was to design the PCB using KiCAD. I began by laying out the submodules, followed by the other necessary components, such as power plug, drill holes and connectors. I took into consideration the placement of the components, ensuring that everything was spaced out correctly and had proper clearance.


Once the PCB layout was complete, I ordered the necessary components from various suppliers, ensuring that I received high-quality components for my power supply unit.

Building the Power Supply Unit

After receiving the PCB components, I began building the power supply unit. I started by placing the submodules on the PCB, followed by the other components. With everything in place, I used a multimeter to check for any short circuits or incorrect connections.

Next, I connected the power supply unit to my +24V external power brick. While checking the voltage output, I discovered that the voltage output of the +5V module was slightly off. To correct this, I turned the screw on the +5V module to set the voltage to a proper +5V and then secured the regulator in place with glue.

With the power supply unit built and the voltage output adjusted, I tested the voltage output using a multimeter. I confirmed that the voltage output was stable at +5V +12V and -12V.


Building a power supply unit for a modular synthesizer can be a rewarding experience, and with the right knowledge and patience, it can be done successfully. In my case, I chose to purchase pre-built submodules from AliExpress, which saved me time but did not diminish the excitement of building my power supply unit.


Using KiCAD for PCB modeling and quality components are essential for building a reliable and stable power supply unit for a modular synthesizer. I hope that this article has provided some insight into building a power supply unit for your Eurorack synthesizer.

If you're interested in building a power supply unit for your modular synthesizer, the sources and documentation for my project are available on my Github.