DASYRAC – the whole story!

Note: This article will be updated with new information and links over time.

DASYRAC (Digital/Audio System Yielding Retro Auditory Coolness) is my voltage-controlled audio mad science lab, containing fifty or so Eurorack synthesiser modules. I started putting it together in early 2017 partly as a 40th birthday present to myself and partly as a practical introduction to electronics. Once I figured out what I wanted from a modular synthesiser setup and how to solder, there was very little to stop me. 🙂

The Eurorack bit

A quick jargon-buster: Eurorack modules have a standardised height of 3U – that’s  133.5mm to the rest of us. The widths of the modules varies wildly and is measured in horizontal pitch (HP for short). 1HP is equal to 5.08mm. My smallest module is all of 2HP and my widest one is a relatively whopping 22HP.

DASYRAC is housed in a 9U (= three rail) 104HP Synthrotek Cheeks Of Steel open rack and an 84HP Tiptop Happy Ending kit rack for a total of 396HP. The modules are powered by two 4ms Row Power 30 supplies yielding a total capacity of 3A on the +12V power rail, 1.5A on the -12V power rail, and 1A on the seldom-used 5V power rail. The powered modules connect into shrouded IDC power connectors at the back and everything runs off a single 90W laptop power supply.

The actual Eurorack modules

Each module is listed with a “rack-up” date. All the dates are for 2017.

The majority of DASYRAC’s modules were built from DIY kits as sold by stores like Thonk (UK), Befaco (Spain), Noise Kitchen (Czechia) or by individual vendors like Sonic Potions (Germany) and WORNG Electronics (Australia). All the kits were supplied with all the necessary through-hole components unless otherwise stated.

Over time I want to build up a commentary about what each module does and how it does it, why I wanted it in the first place, what surprised/disappointed me, whether it actually does the job, sound demos, etc. Since that’ll take a while, the [modulargrid] link will take you through to the module’s entry on Modulargrid where you can read about it while I get my act together.

  1. Doepfer A-138a linear mixer (27 March – 16 November) [modulargrid]
  2. CFM Bipolar Half-Wave Rectifier (kit, 27 March – 6 October?) [modulargrid]
  3. Tiptop uZeus power supply (27 March – 6 October?) [modulargrid]
  4. Erica Synths Pico Input dual amplifier (30 March) [modulargrid]
  5. WORNG Electronics 3x3x3 Passive Mult #1 (kit, 5 April – 16 November) [modulargrid]
  6. Thonk AT-AT-AT triple attenuator (kit, 11 April – 16 November) [modulargrid]
  7. Befaco A*B+C dual quadrature VCA (kit, 15 April) [modulargrid]
  8. Doepfer A-199 SPRV Spring Reverb (18 April) [modulargrid]
  9. Doepfer A-106-6 Xpander VCF (18 April) [modulargrid]
  10. Doepfer A-151 Sequential Switch (18 April) [modulargrid]
  11. Mutable Instruments Links buffered multiple & mixer (24 April) [modulargrid]
  12. Befaco VC Slew Limiter (kit, 29 April?) [modulargrid]
  13. Befaco Rampage dual function generator (kit, 30 April) [modulargrid]
  14. T.I.N.R.S. Tuesday procedural sequencer (8 May) [modulargrid]
  15. 4ms Row Power 30 power supply #1 (22 May) [modulargrid]
  16. WORNG Electronics 3x3x3 Passive Mult #2 (kit, 26 May) [modulargrid]
  17. Bastl Instruments Noise Square waveform generator (kit, 26 May) [modulargrid]
  18. Bastl Instruments Skis dual decay/VCA (kit, 28 May) [modulargrid]
  19. Vintage Synth Lab VCF-74 low pass filter (30 May) [modulargrid]
  20. Befaco Sampling Modulator sample and hold (kit, 10 June) [modulargrid]
  21. Sonic Potions Penrose pitch quantiser (kit, 15 June) [modulargrid]
  22. Doepfer A-185-2 Precision Adder voltage summer (15 June) [modulargrid]
  23. Sonic Potions Mal-2 source of chaos (kit, 16 June) [modulargrid]
  24. Doepfer A-110-4 QZVCO Quadrature Through Zero VCO (21 June) [modulargrid]
  25. Befaco EvenVCO (kit, 24 June) [modulargrid]
  26. Befaco Crush Delay (kit, 25 June) [modulargrid]
  27. Befaco Chopping Kinky dual wavefolder (kit, 25 June) [modulargrid]
  28. Befaco Joystick (kit, 2 July – 21 August, re-rack 18 November) [modulargrid]
  29. Befaco Dual Attenuverter (kit, 7 July) [modulargrid]
  30. Bastl Instruments ABC mixer (kit, 7 July) [modulargrid]
  31. Hexinverter Galilean Moons dual EG/VCA (kit, 14 July) [modulargrid]
  32. Hexinverter Mutant Clap (partial kit, 21 July) [modulargrid]
  33. WORNG Electronics LRMSMSLR stereo/mid-side processor (pcb/panel, 1 August) [modulargrid]
  34. RYO Aperture LPG low pass gate/VCA (kit, 1 August) [modulargrid]
  35. Music Thing Modular Radio Music sample player (kit, 1 August) [modulargrid]
  36. Music Thing Modular Turing Machine mk II stepped random voltage source (kit, 2 August) [modulargrid]
  37. Music Thing Modular Simple EQ (SMD kit, 3 August) [modulargrid]
  38. Ladik L-010 Waveform Animator (7 August) [modulargrid]
  39. Synthesis Technology E560 Deflector Shield frequency shifter/phaser (17 August) [modulargrid]
  40. Eowave Fluctuations Magnétiques quadruple VCF (21 August) [modulargrid]
  41. Expert Sleepers Disting mk 4 swiss army knife (1 September) [modulargrid]
  42. 4ms Row Power 30 power supply #2 (6 October) [modulargrid]
  43. Alright Devices Chronoblob digital delay (6 October) [modulargrid]
  44. Mutable Instruments Ears contact mic/amplifier (6 October) [modulargrid]
  45. Music Thing Modular Pulses mk II random trigger source (SMD kit, 13 October) [modulargrid]
  46. Transient Modules 8S Sequencer (kit, 14 October) [modulargrid]
  47. Bastl Instruments Little Nerd clock manipulator (kit, 14 October) [modulargrid]
  48. Mutant Instruments Clouds texture synthesiser (20 October) [modulargrid]
  49. Horstronic Arcade Button trigger/gate (kit, 6 November) [modulargrid]
  50. RYO VC Sequencer (kit, 7 November) [modulargrid]
  51. RYO TrigXpander trigger source (kit, 7 November) [modulargrid]
  52. 2hp Euclid euclidean rhythm generator (13 November) [modulargrid]
  53. Music Thing Modular Voltages mk II graphic random voltage source (kit, 27 November) [modulargrid]
  54. RYO Optodist overdrive (pcb/panel, 27 November) [modulargrid]
  55. Bastl Instruments ABC mixer #2 (kit, 28 November) [modulargrid]


  • Feedback 106 Chorus (partial kit) [modulargrid]
  • Befaco A*B+C dual quadrature VCA #2 (kit) [modulargrid]
  • Music Thing Modular Spring Reverb mk II (kit) [modulargrid]
  • Fonitronik Cascade attenuverter/mixer (kit) [modulargrid]
  • Doepfer A-124 Wasp VCF [modulargrid]
  • Polaxis Talko linear predictive coding speech synthesiser (kit) [modulargrid]
  • Ornament and Crime digital swiss army knife (kit) [modulargrid]

Patch pals

Patch pals are mini-circuits which live out in “cable space”. They don’t need a power supply to do their job.

  • Befaco 6-Way Mults (23 June)
  • Mystic Circuits 0hp OR gate (kit, 26 October)
  • Mystic Circuits 0hp AND gate (kit, 26 October)
  • Mystic Circuits 0hp Vactrol VCA/LPG (kit, 26 October)
  • LMNTL 6-way mults (27 November)

External instruments

Most of these instruments talk to DASYRAC using voltage control and are where it all started, long ago in the ancient times of January 2017.

  • Korg ARP Odyssey synthesiser (23 January)
  • Korg SQ-1 sequencer (24 February)
  • Arturia Beatstep Pro uber-sequencer (3 March)
  • Arturia Keystep keyboard/sequencer (7 March)
  • Arturia Drumbrute drum machine (28 November)