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My journey into Eurorack & a refresh of electronics

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Feature photo by Adi Goldstein on Unsplash

So what is Eurorack? And how did I get into it?

Modular synthesisers are synthesisers which are broken down into individual components, meaning they can be interlinked (patched) in any order the user wants, and not just how a manufacturer has predetermined. A few years ago, Dieter Döpfer of Doepfer Musikelektronik GmbH repurposed 19″ server rack standards to accomodate modular synths, this new format was Eurorack. Eurorack standardised a lot (but not all) of features which a modular synth component should follow. Eurorack has surged in popularity since, and is now one of the main formats available for synthesisers.

My background

A good number of years ago I studied Electrical & Electronics Engineering at college. My employer at the time was a power distribution engineering company (think factories, wind farms, and high voltage equipment!), so the college course formed part of my training. Needless to say, I was more focused on the electrical side of the teachings, and not so bothered about the electronics. After all, I didn’t really need it at the time.

Fast forward over 10 years, and I’m still in the same industry, although I now work for myself performing compliance simulations and consultancy work, and still not using my electronics training.

One of the more recent studies that I have begun to carry out as part of my work, is to assess the impact a project has on the harmonic content in the surrounding electrical network, and whether filtration is needed in order to bring the harmonic content within limits. The problem was though, I was a little rusty when it came to filters.

I did some searching online to get up to speed with harmonics and filter theory, and low and behold, countless synthesiser articles and schematics appeared in my searches.

Electronics, welcome back!

The equipment I was researching usually costs thousands and are around the size of a shipping container. Not ideal for learning the basics.

This was the point that I thought I’d be better to having a play with fiddly little electronics components in my kitchen instead, and see how I get on. The concepts are the same after all, so time to have a refresh!

Hello Eurorack 👋

Christmas Day 2022, I received my first Eurorack module kit, the EDU DIY Output module by Erica Synths and Moritz Klein.

The documentation for this series was all written by Moritz Klein (except the Output module it turns out), who it turns out is an amazing teacher of electronics concepts, and I can highly recommend his YouTube channel, and the mki x series documentation.

Working my way towards understanding a filter, it turns out Eurorack and the synth DIY (SDIY) world is very addictive.

Instead of just “understanding” the theory, I’ve ended up down the rabbit hole of buying Eurorack module circuit boards, a whole myriad of components, and spending some late evenings in puffs of solder smoke.

From all my reading into synthesisers and electronics, I’ve accomplished my initial objective, and now have a pretty good understanding of how filters work. But what do I do with this new itch to solder, and thousands of excess components?

Make more modules of course!

The plan

Throughout my journey so far, one thing has become very apparent, this has the potential to become a VERY expensive hobby. So I’ve come up with a plan. Probably the same plan as hundreds of other electronic music and/or electronics enthusiasts, and that’s to design and produce my own modules, with a view of selling off any extra PCBs I design to help fund my addiction.

First. Before making any modules, get some other basics down. Each rack needs power and each SDIYer needs to be able to visualise the electrical signal at any point around a circuit, to help with development and troubleshooting. I’ll need to produce a PCB for a power supply, and I’ve already produced one for a simple oscilloscope.

The oscilloscope utilises the Raspberry Pi Pico, and allows the readings to be visualised via an Android app, Scoppy. The PCB can be found at

Scoppy oscillator PCB

Second. I want to do what many have done before me, and create a basic set of modules using tried and tested concepts, just to get me off the ground with my own synth. These modules should all use as many of the same components as possible.

Third. The end goal to be able to sell a number of module PCBs together as a “starter pack”, for anyone wanting to get into Eurorack, and not wanting to spend a fortune.

If I manage to use a limited number of resistor and capacitor values, a handful of basic ICs, and standardise on all other components (jacks, knobs, power sockets, etc), it should help people get going relatively quickly, without breaking the bank.

The brand

It’s rubbish, I know. But it’s something. I can always rebrand later on I suppose! This is a work in progress, so any new name suggestions, branding ideas, or module concepts are very welcome.

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