Building Your First Modular Synth Rig

Building your first Eurorack rig? Here’s a checklist to make sure you have everything you need to get started!If you're reading this, you are probably in the same position a lot of us have been. You're intrigued by the idea of building your very own, one-of-a-kind modular synthesizer, but feel completely overwhelmed by the sheer amount of options and information out there.

You may be wondering if it's even worth wading into the vast ocean of modular synthesis when there are already so many ready-made all-in-one hardware synthesizers on the market today. We're here to clear the air, help you decide if modular synth is right for you, and get you started down the right path.

Why Go Modular?

Synthesizers generally function on similar principles. Start with a voltage that is oscillating at an audible frequency, and then apply other voltages to control various properties of the audible voltage signal. Many of our favorite legendary synthesizers operate on the very same principle, they are just pre-wired to produce and control these voltages in a very defined way, with very specific voltage generators connected to specific control circuits and a very specific signal flow.

The beauty of modular synthesis is that all of that connection and signal flow is left totally up to you! You can connect almost any voltage to almost any part of the circuit, and that allows you a degree of freedom, flexibility, and creativity that a pre-built synth just can’t touch. If getting a new set of sounds in a familiar package is your desire, modular synth might not be right for you.

If you are looking to break out of the mold, build an instrument that is totally unique, you are interested in experimenting with generative or microtonal music, or are just looking for a new creative outlet, trying modular synthesis should probably be high on your list! But where to begin.

If you are looking to get into modular synthesis, Eurorack is far and away the most popular and most accessible format on the market today. There are hundreds of cottage manufacturers making totally unique and never before seen modules. There are huge communities built around building and customizing their rigs, and sharing advice on how to go about getting the sounds you are looking for.

Some Advice Before Starting

Before we get into the checklist, here are a few pieces of advice I offer those who are building their first rig:

Start small and build from there: There’s a reason those huge rigs you see online are so intimidating! Where to even begin? If you start small, you can get comfortable and familiar with the modules you have and experiment within the limitations of a compact rig.

Begin with a goal in mind: What you don’t want to do is go out and start buying every module you think is cool and then figuring out how you might build a system out of them. If you want a cohesive instrument, it's a better idea to get new modules that will help you move toward a specific sound or style. Think ambient, drone, rhythmic, sequencer-controlled, keyboard-controlled, drum machine, or signal processor.

Get a bigger case than you think you are going to need: As you start building out your first system, you will undoubtedly find more modules that you would like to incorporate. If you have totally filled up your rack, that adds an entire new barrier to deal with if you want to try out something new. Especially when just starting out, it's better to have too much space than not enough!

If all this is sounding a bit much, I think that most modular synth users would agree that building your very own modular rig from scratch is a huge time commitment with a steep learning curve.

For those of us who want to get into the world of modular synth and start experimenting without all of the preplanning and option paralysis, many companies have created pre-assembled and carefully curated rigs with their own modules.

Some of the best options available from Vintage King include the Make Noise Black and Gold, Make Noise O-Coast, Make Noise Cartesian, Moog Mother-32, Moog Synthesizer IIIP, Roland System 500, Analogue Solutions Nyborg 24, Malekko Manther Growl, WMDevices And Steady State Fate, and Dreadbox Erebus.

For those of you who are still wanting to start by building from scratch or who just need a primer on the basics of modular synthesis, let’s move on to the checklist...

The Basics

Oscillators And Sound Generators (Where It All Begins)

Whatever your end goal is, it all has to start somewhere, and that somewhere is generating a sound with an oscillator. Whether you choose from a wide array of analog oscillators, digital oscillators, sample players, drum modules, or a totally external audio source, your initial sound has to come from somewhere.

Signal Processors (Shape Your Sound)

Voltage Controlled Filters (VCF)

Sound sources in subtractive synthesis are generally very broadband sounds, so in order to shape the texture of them, adding filters will let you cut out various parts of the signal and leave you with the frequencies that you desire. High pass, low pass, and band pass are common VCFs that allow you to vary these parameters using voltage inputs over time. Most of the character of a synth sound comes from the sound generators and the filters.

Voltage Controlled Amplifiers (VCA)

Where VCFs are used to control the tonality of your synth over time, VCAs are used to control the volume of your synth. Without VCAs, you would end up with a steady droning oscillator with no variation in volume. You can use different modulation sources, such as Envelopes and LFOs, to control how the volume of your synth changes over time, either constantly or as it is triggered by a clock, sequencer, or some kind of keyboard/instrument input.

Suggested Modular Synth Voltage Controlled Amplifier: Intellijel Quad VCA, XAOC Devices Praga, XAOC Devices Tallin, NoiseEngineering Sinc Bucina

Modulation Sources (Envelopes, LFO)

Now that you have the tools to create and shape your sound, it's time to choose the tools to control them. There are endless ways to create Control Voltage (CV) to adjust the parameters of your VCFs and VCAs, but two of the most common are Envelopes and LFOs.

Envelope Generators

An envelope generator creates a one-time modulation in CV every time it receives the cue to do so, and the CV changes based on a few parameters. Most common are Attack, Decay, Sustain, and Release (ADSR) envelopes, but there are other kinds of envelopes that use Rise and Fall, or other variations of the voltage level changing over time.

Low Frequency Oscillators (LFOs)

LFOs are literally oscillators that are able to vary at a rate lower than audible frequencies. If you want sounds that have some ongoing variation over time and not just every time you trigger it, an LFO is a great way to get it. Set rate, depth, shape, or many other parameters to give your VCFs and VCAs some movement!

Suggested Modular Synth Low Frequency Oscillators: Mutable Instruments Tides, Malekko Quad LFO, Malekko Richter Oscillator II, XAOC Devices Batumi

Triggers/Gates

Be it a controller, a MIDI keyboard, or a hardware sequencer of some kind, you are going to need something to generate signals to trigger your modules to start doing something. One of the easiest ways to get started is to use a MIDI to CV interface (link) and use MIDI data from your computer to send trigger, gate, pitch, and other information out into your modular hardware. Another option is to use a MIDI controller to do the same using a similar MIDI to CV interface. Another popular way is to actually incorporate a hardware sequencer of some kind into your Eurorack system.

Mixers, Clock Sources, & More

Now we get to a lot of the more boring, but essential stuff. This category encompasses many modules that may be necessary, but aren’t necessarily exciting in and of themselves. You’ll need to consider some way of attenuating a Eurorack level signal to normal line level if you ever want to be able to hear it through speakers or send it through a headphone amp, or even send audio directly to your computer through an interface.

You may find yourself needing to use a mixer to add several signals together, or a way to create many copies of the same signal. You may just want some more fine tuned control over your oscillators and modulation CV. If you need to control the timing of several different modules, you may need a clock source. There are many tools that you may find that you need over time, and chances are there is a module that does just that.

Eurorack Cases and Power Supplies

Finally, after picking out (and thoroughly researching) a host of possible options, we need to put them in a case and power them up. Like I said before, it's better to have too much space in your case than too little, particularly when you are just starting out. The investment now is very much with the added flexibility in the future. But how to pick out what kind of case you need?

There are two basic kinds of Eurorack cases with some variation; powered, and unpowered. The unpowered ones are basically specifically shaped boxes with rack rails on which to attach your modules, but you will need to make sure and buy an additional power supply module. In a powered case, there are pre-mounted power busboards that carry the voltage necessary to get your modules running.

The most important thing to consider here is making sure that you have enough width in your case(measured in hp) and current in your power supply (milliamps) to fit and power all of your modules. Manufacturers are pretty good about listing these 2 metrics for each of their modules.

Oh, and don’t forget patch cables to connect it all together!

Extras

With the above types of modules in your system, you can get started experimenting with developing some of your first totally unique synth voices, but the fun hardly ends there! Not only is there seemingly endless variety within the standard categories of synth modules, but there are also countless other kinds of modules you can add. There are classic effects like reverb and delay, and modern variations of them. There are effects that are totally unique to modular that are only limited by what is possible to do with electrical signals.

If you are anything like me, at this point you are starting to see the amount of time you are likely going to spend researching and experimenting with different modules to get that sound you are after, or just experimenting to see what new sonic possibilities there are to discover!

Whether you'd like to start building out your first modular synth rig or want to find the latest modules from the best brands, we're here to help! Please contact a Vintage King Audio Consultant via email or by phone at 866.644.0160.