Tech I by I 21.09.17

How to build a modular synth: The ultimate Eurorack buyer’s guide

The rising popularity of modular synthesis means that barriers to entry for those interested in diving into the world of Eurorack have never been lower. However, with increasing numbers of manufacturers producing ever weirder and more wonderful modules, the choices on offer can be overwhelming. Ed Gillett takes a look at the essential pieces of gear you’ll need to start your own modular adventure.

Building a modular system was once the preserve of only the most hardcore synth nerds. Modules were often expensive or hard to obtain, and even once put together, might require detailed technical knowledge and regular upkeep for their owners to make the most of them (or to avoid accidentally blowing their system up). For those lacking a hefty bank balance and a scientific understanding of sound synthesis and electrical engineering, building your own modular setup was largely a pipe dream.

Today, the picture couldn’t be more different: multiple manufacturers’ adoption of the standardized Eurorack format in the 1990s has made modular synths cheaper, more accessible and easier to get to grips with than ever. The number of Eurorack manufacturers and modules has skyrocketed in the last few years, supported by vibrant online communities like the unfortunately-named but incredibly helpful MuffWiggler forum, and tools like ModularGrid, which allow you to design and plan your perfect modular system before you commit to buying anything. There’s also an extremely healthy selection of online marketplaces focused on the sale and trade of used modules and accessories.

If anything, the sheer range of choices on offer can be a problem in itself: with so many options, how should you know where to begin when dipping your toe into the modular world, or how to identify the essential bits of kits to get started?

As a first step, it’s worth familiarizing yourself with the basic principles and jargon behind modular synths. Every modular system contains a number of different modules, screwed together into rows of metal rails set into a case, and connected to a central power supply (this usually sits within the case, behind the modules). Each module either produces or manipulates a combination of audio and control voltage (or CV) signals, with different paths of CV and audio signals patched together between modules using mono 3.5mm (1/8″) audio jack cables.

CV is used to control each module’s sound generation or sound-shaping parameters, like the cutoff frequency of a filter or the pitch of an oscillator: you can think of it as a simpler form of MIDI, if that helps. Module and rack sizes are taken from the industry standards already used for rack-mounted audio-visual and IT gear, hence the name Eurorack: the width of each module is measured in HP units (modules vary from 2hp upwards) while the height of a case is measured in U units (a single row of standard Eurorack modules is 3U tall).

Semi-modular hardware synths

A great starting point for getting your first taste of modular gear and learning the basics of patching is to look at semi-modular synths: these are complete systems which contain input or output sockets for CV and audio, allowing you to re-patch their fixed sound and modulation paths, reimagining how they work or linking them to other pieces of gear to explore otherwise inaccessible sonic possibilities.

Arturia MicroBrute

Arturia’s inexpensive monosynth offers a perfect entry point for those wanting to get an initial taste of modular patching. Not only does the MicroBrute itself offer a huge variety of snarling analogue sounds, perfect for aggressive leads and monophonic bass, its CV patch points allow you to re-route the MicroBrute’s internal LFO and envelope generator via external cables to control the synth’s pitch, filter cutoff, pulse width and more, or to patch in other modules and expand its capabilities.

Roland System-1m

A stripped-down version of Roland’s earlier System-1 synth, minus the keyboard and with the addition of comprehensive CV control in a Eurorack-compatible form factor, the System-1m offers a huge range of features in a futuristic but affordable package.

Four-voice polyphony, dual oscillators, USB / MIDI in and out and tempo-synced effects are features you’d struggle to fit into a rack of individual modules at this price, and Roland’s digital plug-out architecture allows you to swap out the standard audio engine for new firmware, including one modeled on the famous SH-101.

While the neon aesthetic might not be to everyone’s taste, and plugging in CV connections automatically switches the synth into monophonic operation, the System-1m offers one of the highest bang-to-buck ratios of any semi-modular synth.

Moog Mother-32

Like the System-1m, Moog’s Mother-32 marked the arrival of this industry behemoth into the relatively small world of Eurorack. Like the System-1m, it offers a full synth voice with MIDI input and a generous 32 CV connection points, allowing radical reshaping of its signal path and interlinking with other synths.

Unlike Roland’s offereing, however, the Mother 32 is fully analog, from its single saw/square oscillator to its filter and VCA, designed to deliver Moog’s famously rich sound in a modular-friendly form. It also features a powerful 32-step sequencer, which can be used to not only to drive the Mother-32, but also act as the beating heart of a wider modular system.

Power supplies

The essential starting point of any Eurorack synth is a case and power supply. While the two are often integrated together, buying a second-hand unpowered case or building a DIY case can be a cheaper way to get started, either of which will mean you’ll need to buy a separate power supply. For Eurorack beginners, it’s generally safest to go for something which doesn’t require you to do any complex wiring of different electrical components: each of the following options offer a quick, simple solution for powering your system.

It’s worth taking time to double-check all of the requirements for your power supply very carefully: while Eurorack’s centralized standards have helped to reduce the likelihood of accidentally damaging your modules, it remains much more of a risk than with standalone synths.

Each module draws a certain amount of power (measured in Amps) from either the +12 volt, -12V or +5V outputs of your power supply. You’ll need to check the total amount of power demanded by your modules on each of those three outputs (ModularGrid has a useful feature for calculating this) and ensure that the amount of power you need is less than the total provided by your power supply.

Most power supplies also come without a wall plug, so you’ll need to buy one separately with matching amp and voltage ratings. Most shops will be able to recommend a suitable plug when you buy your power supply.

You’ll also need to pay attention to the power connections between your modules and your power supply: even if your system has all the right power levels, you can still short-circuit your modules if you plug them in the wrong way round.

Most manufacturers adhere to the generally-accepted Eurorack standards originally laid out by Dieter Doepfer (including a red stripe marking the -12V supply on each module’s power cable), and include “keyed” connectors which physically prevent modules from being plugged in incorrectly. However, not all of them do: you should always consult the power instructions for each module, and make absolutely certain that you’ve matched the positive and negative connection for each module to those of your power supply before plugging anything in.

TipTop uZeus

The TipTop uZeus is perhaps the obvious power supply for Eurorack beginners, combining a 4hp front panel with power socket and switch, and two flexible power cables with connections for up to 10 modules. Additional power cables can be daisy-chained together for larger cases: the uZeus can deliver up to 1.5 amps of power, enough for a small to medium rack depending on how power-hungry your modules are. Most sellers offer the uZeus without a power cable, so you’ll need to purchase this separately.

4ms Row Power

4ms Pedals’ range of Row Power modules match the basic format of the uZeus, combining flexible bus cables with a 4hp front panel. However, they also offer a substantial increase in power, with the Row Power 30 and 40 delivering a maximum of 2.75A and 4.25A respectively (enough for a small suitcase-style rack, or a medium sized rig). You can also daisy-chain separate Row Power modules together, allowing you to power different sections of a larger system from a single plug socket.


Powered Cases

If you’re not keen on scouring the second-hand market for an unpowered Eurorack case, or building a DIY alternative, then your best option is likely to be a case with a built-in power supply. This is a particular area where options have expanded dramatically in recent years, with increasing numbers of manufacturers offering their own cases alongside their range of modules. While Doepfer offers a tiny and cheap Beauty Case, at 32hp wide it only offers space and power for a maximum of four modules: you’re better off aiming for something with at least 84hp of space in order to put together a decent beginners’ system.

TipTop Happy Ending Kit

If you want the cheapest, simplest all-in-one Eurorack case to get started with, then the Happy Ending Kit is the way to go. This no-frills package includes a uZeus power supply, along with a set of 84hp-wide rails for holding your modules, and a pair of Perspex end cheeks to prop the rack up nicely on your desktop. While the minimal construction doesn’t afford much scope for traveling with your synth, it’s a solid and inexpensive starting option.

Intellijel Performance Case

One of the newer additions to the Eurorack case market, Intellijel’s Performance Case is already being used by Aphex Twin for his live modular setup. With space for two 84hp rows of standard 3U modules, plus another 1U row for smaller “tile” utility modules, Intellijel’s system offers a flexible and solid option for anyone looking to take their synth on the road. The only thing to be wary of is that Intellijel’s format for tile modules is very slightly different to those used in other 1U-friendly cases made by Pulp Logic and others, meaning that tiles made by Intellijel can’t be used in other cases, and vice versa.

Hand-built wooden case by Ross Lamond

Despite the recent boom in the Eurorack market, many manufacturers continue to operate on a wholly personal scale: no-one embodies this better than Ross Lamond, who’s been making beautiful wooden Eurorack cases for several years from his workshop in Peterborough, having originally been inspired by the work of American maker Matthew Goike. Each of his cases are made to order, from smaller “skiff”-style tabletop units to gigantic multi-tier constructions, with Lamond’s exceptional craftsmanship elevating them from mere function towards an artform in their own right.


Once you’ve got your case and power supply, you can get started on the more exciting work of building your system: the obvious place to begin is with an oscillator to generate your synth tones. Analogue oscillators tend to give you a warmer, more classic sound, at the expense of a broader range of different sonic possibilities afforded by digital sound engines.

Analogue Systems RS95E

This classic old-style analogue oscillator is a favorite of Luke Abbott (check out his Against The Clock session featuring no fewer than four RS95Es patched together). Like most analogue oscillators, it offers CV pitch input and a variety of standard waveform outputs (in this case, sine, triangle/saw and square). Unlike many other low-budget oscillators, though, the RS95E’s rock-solid pitch control means that you won’t need to worry about your synth drifting out of tune, and its waveshaping inputs allow for subtle modulations of tone.

Following the retirement of Analogue Systems’ owner Bob Williams in 2015, availability of new AS modules has been patchy, but the RS95E (and its predecessors the RS95 and RS90) crop up regularly on second-hand forums, along with the adapters you’ll need to use Analogue System’s unique power connectors with the more widely-used Doepfer standard.

Mutable Instruments Braids

Arguably the most popular oscillator in Eurorack, Braids is the go-to choice for anyone looking for a powerful and flexible digital sound source for their modular: so much so, in fact, that it’s rapidly approaching the same ubiquity as the Technics 1210s or a Fender Stratocaster. There’s a good reason for this, though: Braids, like all of Olivier Gillet’s Mutable Instruments range, packs a dizzying array of functions into a compact package alongside a meticulously-designed user experience.

Braids includes more than 40 different waveforms, from simple square waves to complex FM synthesis, percussion sounds and multi-note chords. Its modulation inputs allow for complex, evolving patches (it’s a staple of Robert Aiki Aubrey Lowe’s drone-based soundscapes), and it also features a very helpful built-in quantizer to lock its output to specific musical scales. A word of warning, though: Gillet has just announced that he won’t be manufacturing any new Braids modules, so you may have to get to a shop quickly or scour second-hand sites to find one.

ALM Akemie’s Castle

The higher end of the price range for Eurorack oscillators provides an abundance of beautiful, varied and complex sound generators, many of them without immediate parallel elsewhere in the hardware world. This sense of adventure is perfectly encapsulated by the Akemie’s Castle, released in early 2017 by British manufacturer ALM.

Akemie’s Castle captures the unpredictability and extreme sound-shaping potential of FM synthesis, but sidesteps the issues faced by classic FM synths like the DX7, which were burdened with boring menu-heavy interfaces for controlling their hundreds of different internal parameters. By limiting the parameters available and providing physical knobs and CV modulation for each of them, the Akemie’s Castle can produce a huge range of weird and unique FM sounds unlike anything else in Eurorack – without sacrificing the tactile thrill of hands-on control or cross-patching from your other modules.

Modulation sources

One thing that sets modular synthesis apart from other forms of music production is the ability to create entirely new sonic environments from creative patching and mixing of CV signals between different modules. To achieve this, you’ll obviously need modulation sources: these could include envelopes to shape the volume of your sound, LFOs to wobble the cutoff frequency of a filter, or randomness to create shifting, generative patches.

Each of these functions could merit a section to themselves, but for beginners it’s worth considering multi-function modules which allow you to switch between different modulation types; as your synth grows, you can then add specialized modules to match your own patching and compositional style.

Mutable Instruments Peaks

Peaks’ simple layout and small size belies its status as one of Eurorack’s most flexible modules: each of its two CV channels can be used independently as an envelope generator, an LFO or a drum synthesizer, with even more functionality unlocked through “hidden” modes and unofficial user-made firmware. Its snappy and precise digital ADSR envelopes and tempo-synced LFOs are particularly useful for beginners, offering easy-to-use but powerful and essential modulation sources for any synth voice.

Sadly, just as with its sister module Braids, upcoming changes to the Mutable Instruments range means that Peaks has been discontinued in recent weeks, so you’ll need to look out for second-hand sales in order to find one.

Bastl Instruments CV Trinity

The team behind Czech synth company Bastl Instruments have a reputation for doing things their own way, from their enjoyably wacky promotional videos to their immediately recognizable range of wood-paneled modules. The CV Trinity provides six separate channels of modulation, each of which can function as an envelope, an LFO, a 32-step sequencer or a stepped random generator; each channel can be controlled by incoming CV signals, allowing you to patch multiple signals into each other and create wild, shifting modulations.

Unlike the smooth, seamless Peaks, the CV Trinity’s 8-bit processor means that its CV outputs are low-resolution and prone to jumping audibly between different values. Its input controls, also made of wood, can be similarly unpredictable and unhelpful for precise control. As such, the CV Trinity may not be the best choice of module for elegant, slowly-unfolding patches or dialing in specific modulations. If you’re after something a bit more chaotic though, then this is a brilliant and irrepressibly fun choice.

Sputnik Modular Quad Function & Trigger Source

Sputnik, along with several other Eurorack manufacturers, takes its inspiration from the experimental 1960s synth designs of visionaries like Don Buchla and Serge Tcherepnin. Sputnik’s Quad Function & Trigger Source offers four channels of CV, each of which can be used as an LFO or attack-release envelope, or interlinked to form more complex ADSR envelopes and shifting modulations. While the complexities of Buchla’s “West Coast” style of synthesis may make it less immediately accessible for Eurorack beginners than the simpler East Coast style embodied by Bob Moog and others, Sputnik’s range offers a neat entry point for Eurorack owners interested in exploring West Coast ideas.


Every modular system needs space for the less glamorous or exciting modules: the ones which don’t necessarily do much on their own, but enable you to get the most out of your other modules. These can include attenuators and inverters for scaling and flipping your CV modulation signals, multiples to split signals to different locations, or mixers to combine CV or audio from different sources. More complex utility modules can cover a multitude of these essential functions, and create additional space for your more eye-catching modules to shine.

TipTop Audio Stackcables/Modular Addict Stacking Cables

It’s guaranteed that, almost as soon as you start patching a modular system, you’ll need to start sending single CV signals to more than one destination. You might want to send the same envelope signal to the volume of your oscillator and the cutoff frequency of your filter, for example. Where a fixed-architecture synth might already have this routing in place, a modular synth requires a physical cable connection: if you’ve only got one output socket on your module, how do you send the signal to two places?

While one option would be a signal-splitting module called a “multiple”, a more elegant solution is a stacking cable, which adds a socket behind the connecting jack at each end of a standard 3.5mm cable, allowing you to plug another cable in on top of the one you’ve just connected.

The market for Eurorack stacking cables has been cornered for several years by TipTop, which has fiercely protected the patent for its Stackcable design. In recent months, Milwaukee-based synth store Modular Addict made the first real attempt to work around TipTop’s patent, selling similar stacking cables for a fraction of the price, prompting a furious response from TipTop and heated online discussion. Putting all that drama to one side (though for what it’s worth, my sympathies lean more towards Modular Addict): stacking cables remain a hugely useful bit of kit, and well worth investing in.

Expert Sleepers Disting

Best known for its Silent Way software, which allows you to send CV signals from your software DAW to your modular through the audio outputs of any compatible soundcard, Expert Sleepers is one of the most inventive and imaginative producers of Eurorack utility modules. Disting is its smallest module, packing a mind-boggling array of functions into a slim 4hp of rack space.

It can be a quantizer (fixing your CV values to musical intervals), an LFO, a randomness generator, an oscillator, or a delay; it can invert, mix and multiply incoming CV signals. Later models can even be used with an inbuilt SD card slot to become a CV-controlled sampler. Disting’s reputation as the Swiss Army Knife of Eurorack is richly deserved: it’s a pocket-sized solution to a million problems, and is easily one of the most useful utility modules you could ever add to your system.

MakeNoise Maths

The perennially popular Maths from Asheville-based MakeNoise could appear pretty much anywhere in this list: while it’s mostly used as an envelope generator or LFO, it can also act as an oscillator, a VCA, a source of complex CV functions, and more besides. It’s ended up in the utility section for its flexible options around inverting, mixing, comparing and splitting voltage and audio signals, whether patched in from other modules or created by Maths’ two channels of CV generation. It’s a blank canvas for creating and processing a huge variety of CV signals, and rewards creative and imaginative patching. Maths’ benefits are hard to summarize in a short paragraph, but its enduring popularity amongst Eurorack owners is completely deserved, and testament to its many charms.


Voltage controlled amplifiers are the often-unheralded backbone of any modular system. Most commonly, they take an incoming CV signal, and use it to control the volume of an audio signal. Send an envelope to your VCA’s CV in, and you can control the attack and decay of your sound; use an LFO instead, and you get a tremolo-like effect, with the sound fading in and out.

As with everything in Eurorack, though, this is only a starting point for more complex explorations. VCAs can be used to modulate CV signals rather than audio, allowing you to create increasingly strange modulation shapes; sending audio into both inputs of a VCA, on the other hand, can create a lo-fi ring modulator.

There are several very good reasons why the most common answer to Eurorack newcomers asking about their planned system is “you need to add more VCAs”: get your VCA selection right, and you’ll option up a whole new range of creative possibilities.

2hp Dual VCA

While plenty of Eurorack manufacturers have their own quirks or unique qualities, none are quite as strictly enforced as those of 2hp. As the name suggests, every one of their modules, from MIDI interfaces to oscillators, sequencers and reverbs, fits behind a tiny 2hp-wide panel. Their VCA fits two separate channels into this tiny footprint, including attenuators for each CV input and low-distortion circuitry for processing audio signals at high quality. If rack space is at a premium, 2hp’s range offers unprecedented functionality and efficiency.

MakeNoise Optomix

Not all VCAs are created equal, with MakeNoise’s Optomix representing a specific type of VCA known as a Low Pass Gate. LPGs combine a typical VCA with a low-pass filter, meaning that quieter sounds have their higher frequencies reduced, while louder sounds appear “brighter”. Combining this effect with a specific type of chip called a vactrol, which produces softer slopes when controlled by incoming CV signals, give LPGs a looser, more organic sound quality, often mimicking the behavior of real-world instruments.

The Optomix provides two independent LPGs with CV control and tone shaping, plus a combined output for mixing both audio signals together. When combined with Maths and an oscillator like MakeNoise’s own STO, it can be used to make everything from soft xylophone-esque tones to distorted analogue kickdrums.

Cwejman VCA 4MX

Cwejman occupies a rarefied status amongst Eurorack manufacturers. One of the original old guard, their modules tend to be harder to get hold of and substantially more expensive than their competitors’ equivalents. There’s a reason for this, though, with their fastidious construction and peerless sound quality spoken about in hushed tones by longstanding Eurorack fans.

The VCA 4MX is a perfect example of this: 4 independent VCAs of pristine audio quality, along with options to mix the incoming signals and all of the CV input options you could every hope for, in a ruggedly-constructed and no-nonsense design. If money is of less concern for you than sourcing the absolute highest quality modules available, then Cwejman’s range may well be of interest.


Pick any of the most well-known and beloved hardware synths, and the odds are good that its personality and signature sound will have been provided by its filter: think of the acidic squelches of the Roland TB-303, the warm tones of Moog’s classic synths, or the Korg MS-20’s gritty and aggressive filter, subsequently repackaged for their Monotron and Volca ranges. Picking the right filter can be the single most important factor in ensuring that the sound of your synth matches your musical ambitions.

Doepfer A-124 Wasp

It’s perhaps slightly unfair to have overlooked Doepfer modules in earlier sections, given their integral role in the development of Eurorack and their ubiquity in modular setups around the world. Doepfer’s popularity as a starting point for modular enthusiasts, as well as the low cost and no-frills design of its wide range of modules, occasionally leads to the company being derided as pedestrian or sterile, a misconception that’s proved to be nonsense by the exceedingly strange Wasp filter.

Building on the wonky, almost circuit-bent quality of the British-made EDP Wasp synth from the 1970s, cranking up the filter’s resonance can lead it to create insane, warbling overtones and strange purring noises. Available for as little as $80 on the second-hand market, and around $110 brand new, there is no better Eurorack filter for beginners to sink their teeth into.

Koma Elektronik SVF-201 

The SVF201 filter was for a long time Koma’s only Eurorack product, sitting alongside a number of strange and unique effects boxes and its Field Kit electro-acoustic workstation (which comes complete with contact microphones, CV-controlled motors, and a built-in shortwave radio).

The SVF201 is, like all Koma products, strange and unique: its multi-mode filter is possibly the only example in Eurorack to be based on vactrol circuitry (similar to the Low Pass Gates mentioned above), giving it a warm, organic and extremely musical quality. Its multiple outputs also allow for creative mixing of different signals. While it can be a relatively difficult module to get hold of, its unique qualities make it worth seeking out.

Mannequins Three Sisters

The Three Sisters filter is difficult to explain in purely functional terms, perhaps by intention: the description on NYC-based manufacturer Whimsical Raps website feels like it’s consciously designed to obscure the reader’s understanding, closer to freeform poetry than a technical manual. Featuring three linked multi-mode filters with individual and combined inputs and outputs (allowing filters to be patched into themselves or each other) and a wealth of modulation inputs, Three Sisters can be used to create otherworldly, kaleidoscope tones, from resonant bell sounds to self-oscillating chords and spectral oddities. The instruction manual describes it as a “musical instrument for the arrangement of vivid colour”: a suitably gnomic tagline for this enigmatic and spellbinding module.


With an oscillator, envelope generator, LFO, VCA and filter in place, you should be well on your way to creating a full synth voice, capable of replicating or exceeding the potential of a standalone hardware synth. Next up, you can begin to think about effects with which to warp and manipulate your audio. With modular, though, you’re not just limited to putting effects after your synth: you can take the output from a pitch-shifter and feed it back into your oscillator to create strange new frequency-modulated waveforms; use an audio-to-CV module to control your system with the repeating sounds from a delay effect; or create complex feedback loops between reverbs and filters to create abstract resonant drones.

Alright Devices Chronoblob

The brilliantly-named Chronoblob from Alright Devices is a tempo-synced digital delay: send it a regular CV clock pulse from a sequencer, and you can lock delay times to the rhythms of the rest of your system. Chronoblob can function like a tape loop, with the pitch of its output responding to changes in delay time, or act in purely digital fashion for stuttering glitch-like effects. With a generous number of CV inputs, a send/return loop for audio and a rich, analogue-like saturated sound, this is an incredibly flexible and powerful delay module.

Mutable Instruments Clouds

Mutable Instruments’ granular sampler / synthesizer / reverb module Clouds, first launched in 2015, is almost entirely unlike anything else, not only in Eurorack but audio hardware as a whole. It samples tiny fragments of incoming audio, allowing you to recombine these grains into new sonic forms, pitch-shifting them to create alien synth voices from existing audio, or freezing and randomizing them for elegant, slowly-shifting ambient forms.

Used inventively, it can create sounds which are uniquely, jaw-droppingly beautiful. Unfortunately, this can also be something of a double-edged sword: the ease with which lush sounds can be summoned means that it’s often used for little more than generic, reverb-heavy soundscapes. It is absolutely worth trying, but more than any other Eurorack module it demands that you explore it fully rather than taking the easy option if you want it to excel.

Since this article was published, Mutable Instruments has announced that production of Clouds is being discontinued. As with Braids and Peaks, a few units may remain with retailers, otherwise look out for second-hand units, or for details of possible new modules hinted at by Mutable Instruments, which promise more immediate hands-on control and less menu-diving.

4ms Spectral Multiband Resonator

In similar fashion to Clouds, the Spectral Multiband Resonator from 4ms is a perfect source of ethereal, dreamlike tones and drones. It’s based around six band-pass filters, the frequency and resonance of which can be controlled independently. The SMR’s central controls allow you to treat the frequency of each filter as a note in a scale, rotating and morphing between them to create everything from ringing tuned percussion sounds to gently undulating melodies and foggy ambience. Fans include Kaitlyn Aurelia Smith, with this video showcasing the SMR’s charms perfectly.


For most people, the gradual nature of building a modular rig means focusing on an initial synth voice first of all, controlled from your computer or sequencer via a MIDI to CV module. It’s worth remembering to leave plenty of space in your rack for sequencing modules though: the variety and inventiveness of Eurorack sequencers allow you to break free of traditional DAW or MIDI processes, and develop completely new approaches to making and composing your music.

Music Thing Modular Turing Machine

For people with a steady hand and a well-ventilated workspace, building DIY versions of Eurorack modules can be a handy way to get hold of powerful modules for much less than you’d pay otherwise. While the Turing Machine from Music Thing requires some experience of soldering and working with electrical components, it’s a relatively straightforward build and offers some powerful functions. A “random looping sequencer”, the Turing Machine’s stream of random CV values can be locked in place to create looping note sequences of up to 16 steps in length; randomness can then be added back into the system gradually, creating patterns which shift slowly and create unpredictable, generative musical structures.

Doboz Prizma

One of the more mysterious Eurorack manufacturers, with orders seemingly accepted only by emailing them directly, Lithunia-based brand Doboz is nonetheless worth seeking out. Their Prizma sequencer offers an incredibly impressive range of functions in a compact and inexpensive package: it contains two variable-length sequencers, each of which can be run in various directions, fixed to specific musical scales, randomized, and saved to or loaded from up to 16 presets, all in a slimline 6hp form and available for around $160 (or as a DIY module for even less). While the Prizma appears to have flown under the radar thus far, its excellent feature set and incredible value for money deserve far wider attention.

Intellijel Metropolis

Inspired by and licensed from a one-off DIY module based on the classic Roland System 100-M modular, Intellijel’s Metropolis combines a traditional 8-step analogue sequencer with a unique “step length” function, which allows you to hold each of those 8 steps for up to 8 beats. While this sounds simple in theory, in practice it unleashes a dizzying range of variability for your sequences, perfect for creating punchy and unpredictable Detroit-style synth lines; the addition of a quantizer and CV control over different parameters add even more flexibility to this sequencing powerhouse.

Ed Gillett is on Twitter

Update, October 18, 2017: Following comments made by Synthrotek’s founder on social media, we’ve chosen to remove our recommendation of the company’s products from this feature.

Read next: Are modular synths worth the hype? Four artists share their Eurorack secrets



Share Tweet