If you love synthesizers, the Eurorack format can be incredibly appealing — you can build any type of synth you want. But going from keyboard synthesizers or software instruments to an open-ended hardware platform can be overwhelming. While there are seemingly endless options for different Eurorack components (that’s the whole point!), creating your first Eurorack synthesizer is simple once you understand the basic concepts. Let’s clear away some of the mystery around Eurorack, look at what you’ll need to get started, and create a logical flow to start you on the path to your first Eurorack rig.
Set Your Creative Goals
One way to overwhelm yourself at the start of your first Eurorack build is to start searching for cases and modules before having a clear goal in mind. Do you want to build your own version of a classic subtractive analog synth that you plan on playing in real time with a keyboard? Do you envision a unique synth structure that you’ll drive with a sequencer? Maybe there’s a unique Eurorack sequencer module that you’d love to use to drive your other synthesizers? Or perhaps you want to generate ambient soundscapes that you’ll record and manipulate in your DAW? You can build a Eurorack rig to accomplish any of these and other goals, but you’ll want to narrow down those goals before making a shopping list.
Four Things You’ll Need
Let’s start with a macro view — out of all the different ways you can approach building a Eurorack modular synthesizer, you’ll need the same four basic things every time.
First up is a Eurorack case to house all of your modules. You’ll also need a power supply to provide power to your modules. Of course, you’ll also need modules. And finally, you’ll need a set of good patch cables to connect modules to each other. There are tons of options for each of these four necessities, and that’s the beauty of Eurorack. Let’s take a look at each and see how the goals you’ve set for your Eurorack rig will dictate your options.
Eurorack Case
Make sure you have enough space
Your choice of Eurorack case determines many things — how you’ll interact with it, how many modules you can install, whether you’ll need additional modules to handle audio level conversion (because Eurorack signal level is not the same as audio line level), whether you need a MIDI interface to integrate with a MIDI rig, and so on. One major consideration is how much space you’ll need for your modules. This is measured in horizontal pitch, commonly called HP, the standard unit of width for Eurorack modules.
The simple rule of thumb is to get more space than you think you’ll need so you can add modules in the future — but what’s the right size to start with, in general? It really depends on your modules, but for a basic Eurorack rig, somewhere in the range of 80HP–160HP of total space is a good size to aim for. If you already know which modules you’ll be using, add up the total space they need and aim for 10HP–20HP more than that. If you aren’t sure which modules you’ll want, it’s okay to estimate a case size first, just make sure to circle back and confirm your chosen case is big enough for the modules you decide on.
To sum it up, the simplest way to start is with a Eurorack case that already offers a built-in power supply and, perhaps, audio and MIDI I/O, too. You can check out these powered Eurorack cases as a starting point and go from there. However, if there is no powered Eurorack case of the size and form factor you desire, it’s simple to add a power supply module and any audio/MIDI interface modules you’ll need — just make sure to factor those in to the total HP you’ll need.
Power Supply
How to choose one if the case doesn’t have one
For your first Eurorack rig or even your eleventh, it can be a big convenience to choose a case that comes with a power supply. Whether you’re using the case’s built-in power supply or choosing your own, how do you know if a power supply can accommodate all the modules you’ll want? Simply add up the power requirements (given in milliamps, abbreviated mA, for current draw) for all the modules you’ll be using and make sure your power supply can provide more than that. If you’re using a case with a built-in power supply, keep its total amperage in mind as you’re selecting modules — if the modules you want add up to more than the power supply’s total milliamp rating, then you’ll need a case with more power. If you’re going to add your own power supply, wait until you’ve narrowed down your choice of modules, then choose an appropriate power supply.
Modules
Choosing them is the fun part
The beauty of Eurorack is that it can be whatever you want it to be. You can build your own version of a classic synth and add features you’ve always wished the original had. You can create a sampling workstation unlike any other. Or you can tap into the vast world of unique Eurorack sequencers to control your other synths like you’ve never been able to before. This is why we emphasize the need to set your goals early on — it would be a big bummer to fill up a Eurorack rig with cool modules only to find that you don’t really know what to do with any of it. Just remember that, in addition to oscillators and other sound sources, you’ll want some modulators such as envelope generators and LFO modules to manipulate your patches in creative ways. You may want some effects like delay and reverb, and you’ll likely need some audio and MIDI interfacing if your case doesn’t have it.
Patch Cables
Your synth’s nervous system
Patch cables form the integral connections between your Eurorack modules, and you’ll be handling them much more than most of the cables in your studio. Part of the excitement of Eurorack is being able to rewire your rig on the fly, and that means you’ll be plugging and unplugging patch cables constantly. Cheap cables can wear out quickly, leading to intermittent connectivity. It’s better to buy quality cables right from the start than to have to replace them often. Many cables are available in color-coded sets, which can make it easier to visually identify whether a connection is running audio, CV and gate signals, clock signal, or so on.
Some Tips Before You Start
Hopefully we’ve cleared up some things for you — no matter what you want to do with your Eurorack rig, you’ll essentially need a Eurorack case, a power supply (if your case doesn’t have one), Eurorack modules, and patch cables. And if you get a large case and an ample power supply, you’ll have plenty of room to tweak your synth’s layout and module selection until it’s exactly what you want. To sum up, here are some general tips to get you started:
- Do you already have specific Eurorack modules in mind? Add up the total HP you’ll need for them, then choose a case that has more room you can grow into (blank Eurorack panels are available so you don’t leave holes in your Eurorack case in the meantime).
- Do you want to be able to play your Eurorack synth with a MIDI controller or perhaps to sequence other synths with it? Factor in a MIDI interface module or choose a Eurorack case with a built-in MIDI interface.
- To connect your Eurorack rig to a line-level device like a mixer or audio interface, you’ll need a utility module that converts between line level and Eurorack level. Some cases have this built in, which can be a big convenience.
- Remember that most modules (there are some exceptions) will need to be connected to your Eurorack power supply. Power is delivered via ribbon cables that can be expanded to connect to more modules, but you’ll always be limited by the total milliamp rating of your power supply. When you’ve decided on modules, add up their milliamp draw and make sure your power supply can handle the load.
- High-quality patch cables matter. Low-quality cables can quickly wear out and start to crackle when you brush against them. Keep in mind, you’ll be handling these cables more often than other cables in your studio, so get cables that will stand up to long-term use and abuse.
Technical Aspects of Eurorack
Want to learn more?
The point of this article is to show how approachable Eurorack can be without getting lost in technical details that can discourage you from completing your first Eurorack build. But technical understanding is going to be crucial as you grow your Eurorack rig — you’ll need to be familiar with control voltage and gate signals, the building blocks of synthesis, and more. A great resource is Daniel Fisher’s crash course on Eurorack synthesis. You’ll need to understand the concept of control voltage and how it works, which you can learn about in another article by Daniel Fisher on that very subject. Beyond synthesis, you can also learn more about using Eurorack in the mixing process. And for a more comprehensive guide to building your Eurorack rig, check out Sweetwater’s Eurorack Buying Guide.
Excited about building your first Eurorack modular synthesizer? You should be! If you’d like to talk to an expert to help you plan your build, just contact your Sweetwater Sales Engineer at (800) 222-4700.
