From Wikipedia, the free encyclopedia
A 9U Eurorack modular synthesizer containing a variety of modules

Eurorack is a modular synthesizer format originally specified in 1995 by Doepfer Musikelektronik.[1][2][3][4] It has since grown in popularity, and as of 2022 has become a dominant hardware modular synthesizer format, with over 15,000 modules available from more than 1000 different manufacturers ranging from DIY kits and boutique, cottage-industry designers to well-known, established synth mass-manufacturers like Moog and Roland.[5][6][7]

Compact size, 3.5mm mono jacks and cables for patching all signals, and lack of a visual or sonic aesthetic defined by one manufacturer sets Eurorack apart from other modular synthesizer formats, and these factors have contributed to the popularity of Eurorack among both manufacturers and musicians.[8][9]


Doepfer A-100

Before Eurorack, in the late 1970s, several modular systems based on the industrial “Euro” card frames appeared:

  • Elektor Formant (3U or 6U × 7HP, 3.5 mm jacks, 31-pin bus, ±15 V)
  • BME PM10/Axiom (3U × 8HP, RCA/Phono jacks, 31-pin bus, ±15 V)
  • The Synton 3000 (3U × 8HP, 4 mm “banana” jacks, ±15 V) was of similar format, but constructed more like a modern Eurorack synth.

By the late 1980s, these had all ceased production.

Dieter Döpfer built some Formant modules before producing his own systems. His Voice Modular System from the early 1980s was a Eurocard-based "modular" (the modules were non-patchable voice cards etc.) polyphonic synth, but the front panels look very similar to the later A100 modules.

In 1996, Doepfer Musikelektronik released the first Eurorack-format modular synthesizer system, the Doepfer A-100, followed by successive new series of compatible modules in 1997 and 1998.[3] In the UK, Analogue Systems had been independently developing a very similar format, with small technical differences such as the power connectors. Analogue Systems would later change their products to offer Eurorack compatibility.[10]

In the mid 2000s, other manufacturers such as Cwejman, Make Noise Music and TipTop Audio adopted Doepfer's Eurorack format and started designing and manufacturing compatible modules.[11][12][13]

By 2013, the Eurorack format had gained in popularity. Music technology journalists estimated that there were already at least 80 manufacturers offering over 700 modules, greatly expanding the musical possibilities available from a Eurorack system to include sampling and sample manipulation, West-coast-style wavefolding, DSP-based effects and more.[14]

In the mid 2010s, increasing interest in Eurorack modulars prompted large, well-known music technology manufacturers to start producing Eurorack-compatible equipment aimed at this new market. In addition to modules, manufacturers like Arturia started producing outboard devices such as the Beatstep and Microbrute[15] designed to be able to communicate with Eurorack modular synthesizers via 3.5 mm jacks transmitting control voltages.[16] In 2015 Moog released the Mother 32, a Eurorack-compatible semi-modular synthesizer.[17]

By the end of fall 2018, the ModularGrid website included more than 316 manufacturers.[18]


An unpopulated Eurorack case, showing the power bus

For synthesizers, Eurorack is a de facto standard to allow different modules to fit in the same cases and communicate among themselves. The basic requirement is compatibility with the Doepfer technical specifications:

  • Mechanical: A100 Construction Details[19]
  • Electrical: A100 Technical Details[20]


The physical specification is based on the Eurocard standard of:

  • 3U (5.06 inches or 128.5 mm), where height "U" is measured in rack units, rounded for a lip (nb: 3U in standard rack units would be 5.25 inches or 133.3 mm).
  • 1HP (0.2 inches or 5.08 mm), where width "HP" is measured in horizontal pitch units. A card width is generally integer multiples of 1HP, although some manufactures work in multiples of 0.5HP.[21]

Eurorack modules may be further characterized by depth: shallow modules (2.5 cm to 4 cm [1]) can fit into "skiff" cases and are casually referred to as "skiff friendly".


The Eurorack electrical specification[22] defines a common bipolar 12 V DC power bus (+12V , 0 V, −12 V). This can be distributed by one of two connectors with a standard 2.54 mm (0.1 in) pitch:

  • 10-pin ribbon cable, with +12 V, ground, and −12 V pins
  • 16-pin ribbon cable, with Gate, CV, +5 V, +12 V, ground, and −12 V pins

Audio and control signals are exchanged between modules via 3.5 mm mono jack cables. The electrical characteristics of signals are split into three loosely defined categories:

  • Audio signals are typically a maximum of 10 V peak-to-peak (i.e. between −5 V and +5 V).
  • Control voltages can either be unipolar or bipolar. Bipolar control voltages are typically 5 V peak-to-peak (i.e. from −2.5 V to +2.5 V), unipolar voltages between 0 V and 8 V. The V/Octave scale is used for pitch information.
  • Trigger, Gate or Clock signals are digital 0 V to 5 V pulses typically used for timing and event signalling.

1U modules[edit]

Two Eurorack cases with Intellijel-format 1U rows

Several manufacturers offer Eurorack-compatible modules in a smaller 1U tall format, sometimes referred to as "tiles". As of 2018, there are two competing standards for 1U modules, differing mainly in their height. 1U modules manufactured by Intellijel are 39.65 mm high,[23] whereas 1U modules manufactured by Pulp Logic and other manufacturers are 43.2 mm high.[24] Pulp Logic also proposes a more compact power connector for 1U modules, consisting of only three pins.

Module types[edit]

Voltage-controlled oscillators (VCOs)[edit]

The most common source of sound in any modular synthesizer is a voltage-controlled oscillator.[25] They depend on a control voltage, a lot of times routed from external hardware (for example, an analog synthesizer with a CV output, or MIDI signals processed on a MIDI-to-CV converter), to both control pitch, and output different waveforms.

There are various control-voltage standards for determining the voltage/pitch relationship. The most popular ones are "volts-per-octave", where 1 V equals one octave, and "hertz-per-volt", where each octave equals doubling or halving the voltage.[26]

Noise source[edit]

Under the category of source modules,[27] these modules are responsible for producing different “types” of noises (or colors). They can output (1) white noise — where all frequencies in the spectrum are equally powered, (2) pink noise — where there is more power to the lower end, due to its logarithmic nature, (3) brown noise — similar to pink noise, but steeper slope, (4) blue noise — oversimplified, the opposite of the pink noise, with more power concentrated on the higher frequencies, among others.


Under the category of processors,[28] modulators modify an incoming signal.[29] The effects produced are widely varied and a lot of times, modules are built for a specific function, for example:


Another kind of processor,[30] filters are modules shaping the sound by attenuating specific frequency ranges. These modules contain all or a selection of the following: (1) a high-pass filter (where anything above a certain frequency can “pass”), (2) a low-pass filter (anything below a given frequency can pass), (3) a band-pass filter (where anything “in between” two frequencies can pass), and (4) a notch filter (where one cuts a specific range of frequencies out allowing everything else to pass).[31]


Essentially, modules that can both operate as a source or a processor of musical content in the form of CV or MIDI messages. The most common kind are step-sequencers, where each individual musical event is triggered in a “step” of a bigger sequence (or loop).


Utility modules are the ones responsible for expanding certain capabilities of a specific setup. They can be used to combine, split, divide, multiply, quantize, or offset a signal.[32] One example of a utility module is a multiplier, that allow one to send any CV output to many other inputs. Another example are the attenuators responsible for scaling the CV signal with a control knob (much like faders in a mixing console).


A lot similar to the concept in a guitar pedal, effects modules are used to change the sound of an incoming signal.[33] They can be (1) dynamic processors, used to control the level of a signal (like compressors, or limiters), (2) equalizers, used to change the frequency characteristics of a given sound (sometimes in the form of a eurorack mixer module), or (3) special effects, like delays, reverbs, or choruses.

DIY and open source[edit]

A completed Sonic Potions DIY Eurorack module kit

The technical and modular nature of Eurorack often attracts people who are interested in modifying or building their own modules or cases. Many Eurorack manufacturers started off as individuals building "do it yourself" (DIY) modules or offering DIY kits before expanding into production. Building DIY modules can be a gateway to learning more about electronics and physical manufacturing, as well as being satisfying and developing a more intimate connection with the synthesizer as a personal musical instrument.

Some manufacturers such as Befaco, Bastl Instruments and Erica Synths offer some or all of their modules both as assembled products or as kits to be assembled by the buyer.[34][35] Doepfer offers a case and power supply kit, as well as 'low cost' cases designed to be customised and finished by the buyer.

Releasing modules exclusively as open source designs and DIY kits allows designers such as Music Thing Modular to design and release popular modules such as the Turing Machine or Radio Music without having to run a company or invest in manufacturing. Open Source licenses for both hardware and code allow individuals to build the modules from scratch, and companies such as Thonk to offer kits.[36][37]

Some manufacturers do not offer kits or intend for end users to build their products, but release the code, schematics and layout under open source licenses. Émilie Gillet of Mutable Instruments cites transparency and the possibility for customers to customise or modify their modules as driving reasons for this decision.[38]

Notable users[edit]

A patched Keith Fullerton Whitman Eurorack performance Eurorack case

See also[edit]


  1. ^ Coppinger, Sean (Dec 1995). "Doepfer A-100 Review *** Part One". Analogue Heaven (Mailing list).
  2. ^ Groves, Wesley. "Intro to Eurorack Part I: Doepfer's Beginnings and Power Supply Basics". Reverb. Retrieved 24 March 2018.
  3. ^ a b Doepfer, Dieter. "Zeit-Tabelle". Doepfer Musikelektronik. Retrieved 24 March 2018.
  4. ^ "Dieter Doepfer: Completing the Circuit". Ableton Blog. Ableton. 18 February 2015. Retrieved 24 March 2018.
  5. ^ "Modulargrid-Vendors". Modulargrid-Vendors. Retrieved 7 February 2021.
  6. ^ "Modulargrid-Modules". Modulargrid-Modules. Retrieved 7 February 2021.
  7. ^ Scarth, Greg (2013-03-29). "Dreaming of Wires: The Return of Modular Synths". Attack. Retrieved 24 March 2018.
  8. ^ Ferguson, Tom (2 September 2015). "Interview with Olivier Gillet (Mutable Instruments)". Keith McMillan Instruments. Retrieved 1 April 2018.
  9. ^ Wilson, Scott (21 September 2017). "Are modular synths worth the hype? Four artists share their Eurorack secrets". Factmag. Retrieved 1 April 2018.
  10. ^ Reid, Gordon (November 2012). "Bob Williams: The Analogue Systems Story". Sound on Sound. Retrieved 24 March 2018.
  11. ^ Reid, Gordon. "Cwejman VM1". Sound on Sound. Retrieved 24 March 2018.
  12. ^ "About Make Noise Music". Make Noise Music. Retrieved 24 March 2018.
  13. ^ Mishra, Jyoti (April 2009). "The SOS Guide To Choosing A Modular Synth". Sound on Sound. Retrieved 24 March 2018.
  14. ^ James, Al (April 2013). "The Secret World Of Modular Synthesizers". Sound on Sound. Retrieved 24 March 2018.
  15. ^ Preve, Francis (15 January 2014). "Arturia Microbrute Reviewed". Keyboard Magazine. Retrieved 24 March 2018.
  16. ^ Kirn, Peter (17 January 2018). "Arturia's new easy, affordable modular cases also mount to MiniBrute 2". Create Digital Music. Retrieved 24 March 2018.
  17. ^ Reid, Gordon (January 2016). "Moog Mother–32". Sound on Sound. Retrieved 24 March 2018.
  18. ^ "Manufacturers". ModularGrid.
  19. ^ "Construction Details A-100". Doepfer Musikelektronik. Retrieved 8 April 2019.
  20. ^ "Technical Details A-100". Doepfer Musikelektronik. Retrieved 24 March 2018.
  21. ^ Doepfer. "A-100 Construction Details". doepfer. Retrieved 24 September 2020.
  22. ^ "Technical Details A-100". Doepfer. Retrieved 30 December 2021.
  23. ^ "Technical Specifications". Intellijel. Retrieved 24 March 2018.
  24. ^ "1U Tiles". Pulp Logic. Retrieved 24 March 2018.
  25. ^ Lancaster, Tobias. "Eurorack: Getting Started – SynthRacks". Retrieved 2022-11-14.
  26. ^ says, Kenny (2012-10-26). "Voltage-Controlled Oscillator (VCO)". The Synthesizer Academy. Retrieved 2022-11-14.
  27. ^ Austin, Kevin. "CEC — eContact! 17.4 — A Generalized Introduction to Modular Analogue Synthesis Concepts by Kevin Austin". CEC – Canadian Electroacoustic Community. Retrieved 2022-11-26.
  28. ^ Austin, Kevin. "CEC — eContact! 17.4 — A Generalized Introduction to Modular Analogue Synthesis Concepts by Kevin Austin". CEC – Canadian Electroacoustic Community. Retrieved 2022-11-26.
  29. ^ "Sound Synthesis Theory/Modulation Synthesis". Wikibooks. Retrieved 2022-11-26.
  30. ^ Austin, Kevin. "CEC — eContact! 17.4 — A Generalized Introduction to Modular Analogue Synthesis Concepts by Kevin Austin". CEC – Canadian Electroacoustic Community. Retrieved 2022-11-26.
  31. ^ "Synthesis : A Basic Understanding". 2017-05-25. Retrieved 2022-11-26.
  32. ^ Musicpublished, Future (2022-07-14). "How to design your perfect modular system: utilities". MusicRadar. Retrieved 2022-11-26.
  33. ^ updated, Future Musiclast (2022-07-11). "How to design your perfect modular system: effects". MusicRadar. Retrieved 2022-11-26.
  34. ^ Johannes (3 September 2015). "Bastl Instruments DIY Modular – Eurorack im Selbstbau". Gearnews (in German). Retrieved 1 April 2018.
  35. ^ Arblaster, Simon (7 December 2016). "Bastl Instruments ends the year with three new DIY offerings". Musicradar. Retrieved 1 April 2018.
  36. ^ "Getting Started Making DIY Eurorack Modules". Synthtopia. 18 Feb 2016. Retrieved 1 April 2018.
  37. ^ Whitwell, Tom (8 Feb 2012). "Music Thing: A Radio Sequencer, How to Get Into DIY Synth Modules, How to Have Fun". CDM. Retrieved 1 April 2018.
  38. ^ Callum, Fynn (22 July 2015). "Mutable Instruments – Olivier Gillet interview". Red Dog Music. Archived from the original on 1 April 2018. Retrieved 1 April 2018.
  39. ^ "Even Coldplay have a modular synth". FACT. 17 May 2015. Retrieved 24 March 2018.
  40. ^ Bennett, Katie (18 January 2016). "You Can Make Anything Into Music: An Interview With Emily Sprague". Rookie. Retrieved 3 April 2018.
  41. ^ Ludwig, Jamie (2017-11-09). "Gear Guide: For EMA, Guitar is Just the Beginning…". She Shreds. Retrieved 1 April 2018.
  42. ^ Weingarten, Christopher (2015-11-30). "Animal Collective Talk Escaping Reverb on 'Minimal' 10th Album 'Painting With'". Rolling Stone. Retrieved 18 September 2018.
  43. ^ Holkenborg, Tom (2016-03-08). "Synths of Deadpool - Studio Time with Junkie XL". Youtube. Retrieved 2020-01-29.
  44. ^ Avery, Myles (7 September 2016). "8 Artists Making Brilliant Exploratory Music Using Modular Synths". Soundfly. Retrieved 24 March 2018.
  45. ^ "Martin Gore - Erica Synths Garage". Ericasynths. 11 May 2022. Retrieved 11 May 2022.
  46. ^ Reyes, Jordan (7 March 2017). "A Look at 5 Musicians and Their Massive Modular Rigs". Reverb. Retrieved 24 March 2018.
  47. ^ Darst, Nihan (25 August 2017). "The Magic Of Modular Synths (And Why Artists Love Them)". MPC. Retrieved 24 March 2018.
  48. ^ Kirn, Peter (8 July 2015). "Techno Legend Surgeon Breaks Down His Live Modular Set". CDM. Retrieved 1 April 2018.
  49. ^ "In pictures: Venetian Snares' modular-stuffed studio". musicradar. 1 March 2016. Retrieved 1 April 2018.
  50. ^ "ALBUM REVIEW: Vince Clarke – Songs of Silence". xsnoize. 17 November 2023. Retrieved 17 November 2023.

External links[edit]