Modular Synthesis 101: A Guide to Eurorack Modular

This article was originally written in 2015. Like many of my other well read articles, I’m giving them an update for 2025, with more up-to-date information, better writing, audio and visual accompaniment.

If you’ve clicked this link you might well have some understanding of what modular synthesis is, and, when I took the dive in 2013, I thought I did too. But, it turned out there were a lot of gaps in my knowledge. Even with a solid grounding in hardware synths and even some basic programming with environments like Reaktor, the leap was still a big one. A lot of terminology was alien to me, and even though there were some great resources for planning a modular rig, knowing where to start, what to spend money on and how to move forward was perplexing.

Nearly a decade later, there are some fantastic resources helping you do just that. In 2015 when I wrote this article originally, it aimed to be “the thing I wish I’d read when I started out”. It’s one of my most popular articles on the site so I felt it time to update. I’m aiming to try and be both non exhaustive but also comprehensive

There’s a lot of “before you get started, have you considered…?” and then many practical things that once you’ve taken the dive you should be made aware of, that either are not explicit or harder to ascertain if you’re going in cold. So without further ado…

What is a Modular Synth?

To answer this, it’s worth ensuring you’re familiar with how an ordinary synthesiser works. Most analog or software synthesisers comprise oscillators, filters, envelopes and LFOs. Each of these has a broadly fixed or at least inflexible relationship. Whilst this is not inherently limiting to the average user, there is a degree of prescribed usage.

A modular synthesiser is made up of single function modules that are connected manually. The advantages of this are two fold, it means that a) you can combine different modules in a nonlinear fashion and b) their routing is impermanent. There are of course many more advantages (and disadvantages, some detailed below), but the elevator pitch is that modular synthesisers allow you compose music in a different kind of way.

If you are unfamiliar with the basics of subtractive synthesis and signal routing have a read of this.

Some analog fetishists will claim modulars sound better or the like, I don’t buy this argument personally, while it’s not an unrealistic claim it misses the point, at least to me. Digital analog emulation synths sound absolutely fantastic, and to the average user (or listener) the difference might be negligible. Besides, if you want analog synths, why not buy a hardware analog synth?

Environments such as Max/MSP and other visual programming languages allow a greater degree of flexibility with a much smaller cost, but the barrier of entry is much higher, and all the time you are interacting with a mouse and keyboard. For me, a modular’s raison d’etre is that you can do with it what you want, all the time being hands on.

Things you need to know before you start

It’s important before taking the plunge to understand the some sizeable disadvantages. These include:

Inflexibility

Whilst modular synthesis can allow a great deal of freedom you need to understand the limitations compared to working with soft synths in a DAW. Working with MIDI, polyphony, unison, stereo signals etc are all possible, but generally require dedicated modules. Want tempo synced modulation?

Yes you can do that, but most off the shelf LFOs won’t be able to offer it off-the-bat. Want to make chords? Well you’re going to need an oscillator, filter, VCA and envelope per voice, as well as a polyphonic MIDI module. This can all add up, which brings me on to the next major disadvantage.

Cost

There are module manufacturers producing great modules for everyone’s budget, but even the cheapest modules require power and a case, and you’re going to want four or five to get some flexibility. You’ll be hard pushed to find someone who hasn’t felt the need to expand beyond that.

That said, it’s totally reasonable that if you have a very clear idea of what you want to do and plan it really well, a great system can be built without a huge outlay. However, the axiom of music technology is you generally get what you pay for, and that $50 oscillator might be priced as such for a reason.

There are always bargains to be had, and if you’ll be better off learning a few modules rather than splashing out on a tonne and not learning them thoroughly, but the initial outlay of a case and power alone can be significant unless you have some disposable income.

Space

Ironically one of the things that drove me towards getting into modular was the realisation I didn’t have enough space in my modest studio to pump it full of polyphonic analog synths. Modular is more compact, and if you’re intending to build a small-ish live case, or something with fewer functions, then modular can be quite space economic, but as things grow you’ll need a bigger and bigger case and eventually it can consume a whole desk space, so be wary!

Monophonic vs Polyphonic

This has been touched on above but it warrants a dedicated subheading. Polyphony in modular is both expensive, space consuming and fiddly. Creating multiple voices interacting with each other is a reasonable goal, but having four, five or six consecutive voices for making traditional polyphonic choral compositions requires dedicated signal paths and modulation options for each voice.

Things to try before starting

If the above hasn’t dissuaded you and you’re still chomping at the bit then it’s worth spending some time with some or all of the below software solutions to decide if this is still something you can see yourself taking to.

VCV Rack

By far the closest experience to a real modular is VCV Rack, which is also free to download and use without restriction. VCV Rack is essentially an near limitless environment where you can build a modular system free from the costs of owning all the bits in real life.

Reaktor Blocks

Blocks is a digital semi-modular built within the sandbox of Native Instruments Reaktor. Unlike VCV Rack it isn’t open source but there are modules and instruments built by third party developers.

The building blocks at the heart of it are more akin to lego – in that each piece has a singular function but can be built in to larger abstractions. Similarly, in a real modular synth, an oscillator is a module that performs one function but it’s built from a PCB with resistors, capacitors, transistors, diodes etc.

Max4Live OSCiLLOT

The only one on this list I’ve not used extensively so will let you do your own research but it’s within the Ableton Live M4L framework and is a robust digital semi-modular. Unlike Reaktor, there’s less chopping and changing of the different sound components, but a similar level of flexibility exists with the modulation capabilities.

Arturia ARP 2600, Buchla and Moog Modular

Arturia makes some great emulation soft synths, and in the instrument bundle there are a number of semi-modular synths for you to get your teeth into. Each of these models a different vintage modular synthesiser. The ARP 2600 is probably the easiest to get your head around at first glance, but I’d still not recommend it for anyone unless they’re already familiar with basic subtractive synthesis concepts.

Forgive me Lord, For I have Synth: A Guide to Subtractive Synthesis

The Moog Modular has a bit more going on and is easier to get lost in. The Buchla is the smallest but by far the most fiddly and least welcoming of the three. Some of the terminology is less welcoming and out of kilter with what you might be familiar with using more modern soft synths. This is partly because of the design objectives by the Don Buchla, which we might lump under the west coast synthesis umbrella.

This is a great video by Look Mum No Computer on him unboxing a Buchla.

Max/MSP

Max is perhaps the black sheep  of this list as it’s closer to a programming language than a semi-modular. It’s also the most flexible of this list. I’m not going to going into too much detail on what MAX is capable of because we need to stay on task but MAX allows you to create any synth, drum machine, music making environment, digital FX, sampler or instrument you can think of. You can also connect it to third party APIs, it’s totally interactive, works with video, plays well with hardware etc

If Reaktor is like the Apple of modular, MAX is probably more close to Linux. This is a horrible comparison but I think it makes my point to some degree.

Things you need to know once you start

Eurorack vs the Other Formats

The dominant format of modular synthesisers in the last ten-fifteen years has been eurorack. This is a standardisation of size, power consumption, voltage scaling and various other specifications. I’ll only be discussing eurorack in this article as it’s all I know.

Doepfer and Analog Solutions are the companies who pioneered the format in the late 90s and early 00s. Eurorack then exploded in the early 2010s with many hundreds of companies making modules from small DIY outfits to mid-sized production line operations to well-established companies like Roland, Moog and Waldorf.

Eurorack is popular for several reasons, most notable for the (relatively) low cost compared to other modular formats and the vast array of manufacturers producing modules in this format. However, there are other formats available, including but not exclusive to Serge, Buchla, Moog, Synthesizers.com, MOTM, Frac and more.

My own personal assessment of this: the other formats are probably for more advanced, dedicated users who might already have a eurorack system. If you are a beginner (which is who this article is squarely aimed at) I would avoid considering these unless you are completely clear about what you want to do!

Cases

Once you have some modules you’re going to need to house them in some sort of case. There are numerous solutions available so I’m only going to detail a small few.

Starting Out Small – TipTop Audio Happy Ending Kit, Intellijel 4U Palette Case and Make Noise Skiff

The TipTop Audio Happy Ending Kit (or HEK for short) is a 3U rack-mountable bracket that includes a dedicated power supply (TipTop uZeus Power Module), ribbon cable for connecting modules and power supply. This was my first foray into eurorack. I quickly outgrew it but it gave me the chance to dip my toe.

The other beginner/starting out options I’d suggest are the intellijel 4U Palette Case and MAKE NOISE Skiff.

Analog and Digital

A huge consideration is whether a module is digital or analog. Personally I am unfussed by the sonic comparisons, I’ve heard analog modules kick out a tonne of bass but at the expense of instability, while digital modules to some might sound colder but have precision and typically more flexibility.

Analog modules will generally consume less power and be simpler in their operation. Digital allows menu diving, patch storing and much more processing power.

Power Consumption and +5V

Each module draws power from the case’s supply, typically across +12V, -12V, and sometimes +5V rails. It’s vital to calculate total power usage and ensure the supply has adequate capacity with some headroom (20–30%). If a module requires +5V and your case doesn’t support it, a +5V adapter can often solve the issue. Always check your system’s power requirements to avoid malfunctions.

HP and Depth and 1U Modules

Eurorack modules are measured in HP (horizontal pitch), where 1HP equals 5.08mm. Case width determines module capacity, while depth dictates compatibility with modules. Shallow cases like skiffs may not accommodate deeper modules, so check module depth against your case’s specifications when planning.

1U rows add utility modules like mults or audio I/O without taking up 3U space. Be aware of format differences, such as intellijel and Pulp Logic, as they aren’t interchangeable. 1U modules are a great way to expand functionality while saving space in your main rows.

CV, Gate, Trigger and Audio

There are a few different signal types so it’s worth familiarising yourself with them to properly understand how to get patching.

Audio is the simplest to get your head around: this is a produced sound that can be heard. For example, an oscillator produces audio signal, you plug that into the Audio In on a filter and there’s an output that produces the resulting, effected audio.

CV stands for controlled voltage and comes in a few different forms, too. If we want to modulate said filter, we can take an LFO or an envelope and plug their output (not an audio signal) into the CV control. This is a continuous signal that isn’t heard, but its effect is.

Gates and triggers are both binary signals that can be represented as pulse waves. Where as triggers are a short blip indicating clock divisions or triggering a drum machine, gates are note on/note off informing how long an envelope should stay open, for example:

Here we can see the note on information is the red dotted line, and note off is the blue. Audio signals are at an audio rate (20 Hz to 20 kHz) and can be heard as a sound in the form of an alternating current (AC) which has an audible frequency (pitch) and amplitude (volume).

CV signal is direct current (DC) and could be pitch information, an LFO, envelope or any other modulation source.

Gates are high when a note is depressed and low when it’s released. This would normally come from a keyboard rather than a sequencer.

In this example the trigger hits at the same time as the gate but is momentary. Triggers could also be plugged into a sequencer with clock information, but we’ll cover that in more depth another time.

Where to start? What do you want to do?

• Make songs?
• Make weird sound design noises?
• Improvise?
• Make techno?
• Make ambient noises?
• Make instagram videos?
• Studio tool?
• Inspiration?

It’s worth trying to be honest with yourself about your aspirations before starting out. Unfortunately, if you’re hoping to be able to make full songs with chord changes and polyphony and loads of posh stereo FX, you’re going to have to sink a lot of money and time into this already costly hobby.

What I started out by doing was building a simple SH101-like voice with an oscillator, filter, envelope and VCA all from Doepfer. After this I began expanding that with some simple utilities (envelope follower, random voltage, audio send/return). From there I gradually expanded it with clock generators and sequencers before eventually deciding what I wanted to do, which was make sequenced analog sounds linked with the computer.

That clarity took time to achieve and when I knew what I wanted to do, it made me for focused on purchasing the correct modules to achieve this. Down the line I ended up getting into a lot of things that initially didn’t interest me, such as doing drums with modular and buying stereo FX modules.

Resources

Here are some essential modular resources you need to be aware of. First off there’s the ultimate modular planner, Modulargrid. This allows you to virtually construct a hypothetical modular system, planning where modules will go allowing access to their cost, power consumption, depth, HP and functionality.

The number one resource for asking questions is Modwiggler (and by proxy their facebook page and an unrelated subreddit). No matter how much you think you know, it’s always worth asking the question. No doubt someone else has asked themselves your question before, made the mistake and can hopefully navigate you away from making the same error too.

The two best modular dedicated YouTube creators are Divkid and mylarmelodies. Divkid’s videos tend to be mostar instructional, product demos while mylarmelodies focuses on conceptual topics and long form discussion. Both are worth subscribing to.
Divkid – https://www.youtube.com/user/divkidvideo
mylarmelodies – https://www.youtube.com/channel/UCz0l5LJhNQkktxKWcGUtWxg

Note from 2025 Ali: this might well be an outdated set of resources. I’m not AS connected to the modular world as I was and there are no doubt countless great YouTube resources that I’ve not listed but I stand by what is here.

The world and their dog has written guides to getting started with modular (ahem), so this list is a shorter, more concise list of genuinely good resources, rather than SEO-driven bandwagon jumps (no offence if I’ve missed yours!).

SoundOnSound’s excellent starter guide from way back in 2009 was the straw that broke the camel’s back for me – I pretty much instantly decided this was for me. There’s tons of useful info about all the formats (specialising in eurorack) and is well written and informative.

Learning Modular is a huge resource with a great glossary and video content as well as a coffee table book available for sale.(Patch and Tweak). https://learningmodular.com

ANDREW HUANG. YouTube channel focused on all things music, Andrew has been building a modular since about 2017 and regularly makes good modular videos.

Noise Engineering. There are lots of module manufacturers that have made modular how-tos but Noise Engineering is one of the better ones. They also do good blog content teaching you more advanced modular concepts. Read: https://noiseengineering.us/blogs/loquelic-literitas-the-blog/starting-out-in-modular

Perfect Circuit is a US distributor/shop. While I’ve never bought anything from them I do appreciate their written and video content, of which there is a lot. Read: https://www.perfectcircuit.com/signal/planning-your-first-eurorack

intellijel is another manufacturer, specialising in packing a lot of features into small spaces. Read: https://intellijel.com/support/eurorack-101/

Module Types:

If you know a little about subtractive synthesis or analog signal path, a number of these subcategories will be obvious to you. Or, if you have a basic grounding in computer science or electronic circuits, other modules such as logic or comparators might make more sense to you. In each category, where applicable I’ll make some recommendations for modules that either I own and like or that are clear front runners for that function.

Things that Make Sound

Let’s start with the all important sound source. As with everything in modular, modules can either be fully analog or digital (all digital modules will still have analog control voltage interfaces, their signal processing will be digital though). These modules generate sound that can be sequenced, manipulated, shaped and sculpted into the final result.

Oscillators

The simplest type of tonal generator is a bog standard oscillator, ordinarily referred to as a VCO or Voltage-Controlled Oscillator. These produce periodic wave functions whose pitch is typically controlled by a keyboard, LFO, sequencer, envelope or other modulation source. Oscillators produce a tone as soon as their output is patched to an amplifier.

The main varieties of oscillators are standard analog (sine, triangle, pulse, sawtooth), or digital oscillators such as  wavetable, frequency modulation or physical modelling. Some modules combine multiple oscillator styles, such as Mutable Instruments Plaits.

In terms of what’s on the market, the world is your oyster really. For analog oscillators you’ll have to consider the HP/depth/functionality trade-off. Oscillators that have octave switches are great and save space. Purists may hate me but a sawtooth is a sawtooth, and while you might like the sound of a Moog over an Oberheim, the general application of these are all the same, and it doesn’t make a huge difference what you choose.

For digital oscillators the overall functionality and sound is arguably more important. The aforementioned Plaits is very popular, complex oscillators such as those by MAKE NOISE or Verbos Electronics will offer wave folding, FM, cross modulation and wave shaping, but at the tradeoff of a large HP footprint.

Drum Modules

Like oscillators, drum modules come in both analog and DSP flavours. TipTop Audio’s 808 and 909 modules are slim and simple to use, while Hexinverter offers larger but more customisable and aggressive sounds with their take on the X0X market.

Noise Engineering‘s Basimilus Iteritas is at the other end of the spectrum, a digital voice specialising in crazy industrial techno tones. Plonk by intellijel is a physical modelling oscillator that’s great for percussive tones.

Sample Playback

It’s possible to trigger audio files, normally stored on a microSD card. This has a large crossover with drum modules but you can load anything your heart desires such as foley, pad sounds or spoken word.

For drum playback, TipTop Audio’s ONE is a simple sampler, but for those wanting multiple drum voices the ALM Busy Circuits Squid Sample or Squarp Instruments Rample are more involved multi-voice samplers.

External Input

Want to run an instrument or microphone into your modular? There isn’t much to say here other than think about functionality. Some external inputs will have inputs for XLR and jack, others (such as the Dopefer A-119) have an envelope follower and gate output too.

Noise generators

Lastly there are modules dedicated to generating noise. I could have included this in the oscillator section but it functionally they feel different. Noise is non-tonal, meaning you can’t play melodies or sequence riffs in the same fashion as an ordinary oscillator. Noise is great for adding sizzle or crackle for sounds, creating snare drums, hi-hats or riser effects, as well as as a modulation source, either at audio rate or subsonic.

Like external inputs, noise is noise, so consider additional functionality you might want. The MAKE NOISE Wogglebug is a reasonably sized module considering how much it has to offer.

Things that modify sound

Once you have your sound source, you’re going to want to shape it in some way.

Filters

Most filters will offer a low-pass filter circuit. These are typically referred to as a VCF or Voltage-Controlled filter. Some will additionally offer a band and high-pass filter, but it’s rare to find those features on their own. Like oscillators, the sound of filters is personal choice, and the best thing you can do is to try a few and see what you like the sound of.

A filter is likely something you’ll be adjusting a lot, so consider the size of the buttons or faders, how many inputs does it have? How many modulation inputs are there? Does the resonance sound good when you crank it up? Does it distort in a pleasant way? Does it do more than just a low-pass filter? Etc etc

Effects

The plethora of effects available in eurorack is too vast to list, so I’ll keep it short. Analog/acoustic type effects include spring reverbs and echoes, but there are a wealth of DSP reverbs and modulations too.

Beads (Mutable Instruments replacement for the popular Clouds) is a good place to start for granular manipulation, but simple echoes and reverbs are often all you need to inject some three dimensional quality into your patches. If you’re looking for a smaller imprint then Pico DSP by Erica Synths offers customizable stereo multi-fx in only 3HP.

Ring Modulation/Wave Folders

These could have fit under effects but feel worthy of their own sub-category. Ring modulation is a type of amplitude modulation that creates atonal, metallic sounds. Wave folders are a type of gritty distortion.

Resonators

Five or so years ago I don’t think resonators would get their own heading here. Resonators sound similar to physical modelling oscillators. They work using tiny dela-lines with feedback loops to create clever comb-filtering, similar but not identical to karplus strong synthesis.

CV pitch modulators

Modulation is a big category, so I’ve split it up. Let’s start with modules focused on altering the pitch information of oscillators.

Pitch Quantizers

These modules quantize, or fix the pitch of an incoming CV to a scale, beit chromatic, major, minor, pentatonic, modal, synthetic scale, etc An incoming modulation source would typically be sequencer but could be an LFO, sample and hold signal or anything else. The result is a series of pitches normally snapped to 12TET which can be used to make your melodies more musical.

Most quantizers will offer the basic functionality of allowing you to select a selection of notes for the incoming CV to be quantised to, so look out for other functionality packed into the same space. If this is something that’s going to be key to your patches consider splashing out on something with bells and whistles on. I love my intellijel Scale2 for menu diving but the Penrose Quantizer is simpler (and cheaper) and outputs a gate when a new note is triggered.

Slew Limiters

This is a term that was new to me when getting into modular. The short answer of what these are is something that adds portamento, or glide to your overlapping notes. Sometimes a slew limiting effect can be achieved with a function generator such as MAKE NOISE MATHS or alternatively a dedicated module is suitable. This shouldn’t need to take up too much space.

Precision Adders

A very useful module that combines two or mode signals and allows precise offsets of voltage, normally octaves but it could be other smaller musical intervals. One great application of a precision adder is combining a faster sequencer with a slower one, creating a transposing sequence.

Like quantizers they all basically do the same thing – a great place to start is the vpme.de T43 which has multiple switches for octaves, third and fifths, two inputs and a switchable input, all in just 4 HP.

Modulation Sources

These modulation sources are typically used to module filter cutoff, wavetable index, FM amount, pitch, volume, panning, envelope decay length, anything!

LFOs

Standing for low-frequency oscillator. Simple LFOs will offer you geometric wave functions, more complex ones could have voltage controlled rates, less common wave shapes or any number of CV-able features.

Envelopes and Function Generators

There are two envelopes that you’ll come across more than others, your standard ADSR envelope and a simpler AD/AR envelope, found in drums synthesis and great for snappier, sequenced sounds.

MAKE NOISE MATHS is one of the best examples of a modern function generator – it has rise/fall envelopes with variable curvature of the stages. They can be looped to turn into LFOs or oscillators, there’s two attenuverters (more on this later), basic logic and more. The module can be used to do a plethora of operations, so it’s a fantastic addition to any system big or small.

Sequencers

A rich source for modulation, normally hooked up to the pitch of an oscillator (perhaps via a pitch quantizer) or the filter cutoff of a low-pass filter.

Interactive/Controllers

There are some great ways to add some human touch to your modulation sources.

Random Sources (and Sample & Hold)

Lastly, one thing modular systems do well is randomisation. Random CV signals are non-cyclical modulation sources that offer something close to analog random. This can be smooth or in the case of sample & hold, a stepped random modulation. Sample and hold works by an external or internal trigger “sampling” the signal and output a static voltage at that trigger. There is some degree of crossover here with noise sources, and often these modules are one of the same. In-fact, you could consider a random noise source to be a slower noise.

Stuff that Specifically Deal with Triggers & Clocks

Now we’re getting into the nitty-gritty. It’s necessary to first discuss what a trigger or a clock is. A trigger is a short impulse signal, similar to a gate but with a momentary duration. These are great for triggering a drum module, plucking an envelope, exciting a resonator or physical modelling oscillator or being used in a logic circuit.

Clocks are just a regular series of triggers typically used for advancing a sequencer or connecting to devices that you want to have some semblance of tempo synchronisation, such as a delay or LFO.

Clock Generators

Importantly we want to generate clock pulses from somewhere, be they fast, slow, regular or syncopated. You can get a clock source from your DAW, an external sequencer or from a dedicated module. I’m not going to exhaustively list every clock source available but my recommendation to anyone starting out would be Pamela’s New Workout by ALM Busy Circuits.

Clock Dividers/Multipliers/Modulators

Once we have a clock signal we can modify that in some way, dividing it to slower rates, multiplying it to faster ones or modulating that clock pulse in some other way, such as randomly skipping steps or adding bursts to them. 4ms make a Shuffling Clock Multiplier and a Rotating Clock Divider. As for bursts I like the S-075 by ladik.

Euclidian Sequencers

Without labouring the mathematics behind what Euclidian Sequencers do, in short, they are a fantastic and quick way to get dance-floor-ready rhythms into your modular. The principle is you have a length and density. The length could be four or eight, but equally odd and prime numbers work great too, five, seven, eleven etc. The density is the regularity of the triggers found in this loop. Sometimes there’s also the ability to offset that cycle too.

Other Trigger Generators

There’s multiple ways to sequence triggers. Launch Codes by Antimatter Audio allows you to tap triggers or gates into several pads which can be quantized to an incoming clock signal. DinSync’s Amnesia is a simple 8-step trigger sequencer or there’s the Pulses expander for the popular Turing Machine by Music Thing Modular. This is only really scratching the surface of what’s available though, most sequencers will offer a trigger output for each step.

Things that Connect to your Computer

All of this is great, but from early on I had a huge desire to make music that I could build upon within my DAW, adn quickly I wanted to be able to send MIDI to and fro the modular, as well as later on synchronise it with Logic/Ableton and route audio in and out of it via USB.

You might to want to send any of the following to and fro your modular

• MIDI including clock information
• Audio
• Control voltage (via bluetooth, DC coupled audio cable)

Utility, Logic and more (i.e the Important but Boring Stuff)

I say boring but I don’t truly believe that. This is really the plumbing of your modular, the stuff that makes it work, the stuff that I’m more interested in hearing about in others peoples’ systems rather than what combination of oscillators, filters and FX they’re using.

Multiples

These modules allow you to duplicate a signal. There are two varieties, buffered and passive. Buffered multiples require power and are best for signals such as pitch CV where any loss of voltage would cause it to go out of tune. Passive multiples don’t connect to your busboard and are fine for LFOs, envelopes, triggers, clocks and everything else.

You can use stackable cables, but I find once you’ve connected two or three things to one of these, the weight can slowly damage the jack connector output on the module.

Offset/Attenuators/Inverters

Boy, I wish I’d known about these earlier. Offsets add a static bias to a signal. Attenuators work in the opposite fashion, reducing the strength of a signal. Inverters flip a signal upside down. Sometimes you’ll get an attenuverter – which basically combines those two functions to allow a degree of inversion.

Logic/Comparators

Another thing I wish I’d understood sooner was Logic. There are many different types of Logic but the only two I regularly use is AND gates and OR gates.

Comparators output a gate when a signal (usually a control voltage but could be an audio signal) passes a threshold. These are not as common as other logic gates but handy.

This is best explained by Professor Brailsford from the excellent YouTube channel Computerphile. Note logic is normally discussed with binary numbers 1 and 0, which equate to on and off. For our purposes, when a note is on the gate has an output of 1 and when the gate is off the output is 0:

I am in the process of writing a dedicated logic gate for modular guide. So watch this space.

Mixers

Mixers can take multiple signals and sum them together to one output. The best mixers will allow you to mix audio or CV, so ensure you get one that can do both.

VCAs

Standing for Voltage Controlled Amplifier, these are a bit like attenuators (or a glorified volume control)  but the amount of attenuation is controlled externally by a control voltage signal such as an envelope or LFO. Like mixers, VCAs can be for audio, CV or both, so ideally look for one that is multi-purpose. The adage is you can never have too many VCAs.

Switches

Last on this list is a switch, or voltage controlled switch. This could be things such as mutes (for audio or CV), OR combiners with a switchable output. Normally though these refer to a voltage controlled switch which allows signals to be routed to different destinations or the opposite; to route multiple signals to one output (switchable via CV).

Conclusion

If you got to the end of this and you still don’t understand, or you would prefer to sit back and have someone far cleverer than me explain it, you can check out this excellent set of videos by The Tuesday Night Machines where he’s explained nearly everything you need to know in handy YouTube clips. Check them out:

Also, this sticky of ModWiggler is an absolute no-brainer for anyone starting out and the lovely guys at Synthopia have chipped in with their two cents on Eurorack companies.

In the coming weeks and months I’ll be adding new modular guides on the basic operation and patching of some of the above modules, how to clock your Eurorack with Ableton/Logic, how to get into audio processing and whatever tickles my fancy. Enjoy and happy patching!

If you’ve gotten this far and want to read on, check the next instalment in this series, Modular 102: East Coast Synthesis in Eurorack.

That’s all folks! This article has been overdue a birthday so hopefully I’ve righted some of the wrongs from the original while keeping it relevant. Please feel free to fire any questions you have at me in the comments sections.

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