Vieux Néant

Modular drum & texture instrument — 20-module Eurorack system, 313 HP across 3 rows

Purpose

This system is the result of research into how to build an improvisation-based drumming instrument for experimental electronic music — one where rhythm, pitch, and timbre aren't programmed in advance but shaped live. Designing it meant working across several overlapping bodies of knowledge at once:

Traditional music relationships — sequencing, pitch, rhythm, and their interdependence, since a percussion instrument still needs a coherent relationship between clock, trigger, and pitch/CV even when none of it is fixed in advance.
Tone and timbre — synthesis method (digital, modal/physical-modeling, granular), and how each contributes a distinct percussive or textural character.
Improvisation in "new musics" — designing for a performer who reacts and shapes the instrument live, rather than a fixed compositional structure.
Electronic distribution — the practical signal-routing layer underneath all of the above: buffered multiples, utility/multi-function modules, and CV distribution that let one gesture or clock reach several destinations reliably.

The result is documented below the way any signal system would be: as a functional signal-flow architecture, and as a power/space budget across a physically constrained case.

Instrument signal architecture

Grouping the 20 modules by function (rather than by physical position) shows the actual signal path from clock to stereo output:

Signal flow from clock to stereo output, grouped by function

Functional groups

Group	Modules	Role
Clock, sequencing & CV utility	After Later Audio uT_u (Temps Utile clone), After Later Audio uO_C (Ornament & Crime clone), Expert Sleepers Disting mk4, After Later Audio Mult	Generates and distributes clock/trigger timing, quantizes and processes CV, and buffers signals out to multiple destinations
Percussion, drum & tone sources	Noise Engineering Basimilus Iteritas Alter, After Later Audio Atom (uElements), Mörk Modules Elements, After Later Audio Pique (uPeaks, 1U), After Later Audio Pique (uPeaks, micro), Mutable Instruments Braids, Make Noise 0-Coast	The instrument's sound-generating core: a dedicated digital drum synthesizer, two modal/physical-modeling voices (Elements, micro and full-size) for struck/plucked timbres, two Peaks-derived function generators for percussive envelope shaping, a macro oscillator, and a self-contained semi-modular voice
Texture, filtering & processing	After Later Audio Monsoon (Clouds clone), Mosaic Low Pass Filter, After Later Audio Popple (Ripples clone)	Granular texture processing and two filter voices (dedicated low-pass, multimode) for shaping the raw synthesis output
Sample playback	ADDAC System ADDAC111 Ultra .WAV Player	Introduces recorded material alongside the synthesized voices
Performance & gestural control	Erica Synths Black Joystick2, Synthrotek Echo	Live, recordable gestural CV control and a CV echo for rhythmic/generative feedback — the instrument's improvisation surface
Mixing & FX	WMD Performance Mixer, Endorphin.es Milky Way 1U, Mosaic Mono Reverb	Combines all sources and applies stereo FX (16 algorithms) and reverb before output

Power and space budget

Eurorack modules are constrained on two axes at once: horizontal space (HP, "horizontal pitch") per row, and current draw on three DC rails (+12V, −12V, +5V) shared by the whole case. Designing this instrument meant budgeting both simultaneously across three rows:

Per-row module count, width, and current draw, summing to the case total

Row	Modules	Width	Max depth	+12V	−12V	+5V
Row 1	4	72 HP	42 mm	279 mA	42 mA	0 mA
Row 2	8	124 HP	50 mm	1,020 mA	675 mA	175 mA
Row 3	8	117 HP	42 mm	922 mA	90 mA	0 mA
Total	20	313 HP	max 50 mm	2,221 mA	807 mA	175 mA

Row 2 alone draws roughly half the case's total +12V and the large majority of its +5V current, mainly from the performance mixer and the two power-hungry synthesis/utility modules (ADDAC111, Atom/uElements) sharing that row — a reminder that HP budget and power budget don't scale together, and a case that fits physically can still be short on current headroom.

Full module reference

Module	Manufacturer	Row	Width	Depth	+12V	−12V	+5V
Milky Way 1U (black)	Endorphin.es	1	22 HP	42 mm	117 mA	12 mA	0 mA
Pique (uPeaks, Black, 1U Intellijel)	After Later Audio	1	22 HP	—	60 mA	2 mA	—
Low Pass Filter (Black Panel)	Mosaic	1	14 HP	38 mm	20 mA	20 mA	0 mA
Mono Reverb (Black Panel)	Mosaic	1	14 HP	28 mm	82 mA	8 mA	0 mA
Performance Mixer (black)	WMD	2	40 HP	45 mm	450 mA	430 mA	0 mA
Popple	After Later Audio	2	8 HP	—	35 mA	35 mA	0 mA
ADDAC111 Ultra .WAV Player	ADDAC System	2	16 HP	30 mm	150 mA	150 mA	—
Atom (uElements)	After Later Audio	2	18 HP	34 mm	130 mA	10 mA	—
Braids (old version)	Mutable Instruments	2	16 HP	20 mm	15 mA	15 mA	85 mA
Basimilus Iteritas Alter (Black)	Noise Engineering	2	10 HP	28 mm	80 mA	5 mA	90 mA
Echo	Synthrotek	2	4 HP	50 mm	40 mA	20 mA	0 mA
Monsoon	After Later Audio	2	12 HP	22 mm	120 mA	10 mA	0 mA
0-Coast (eurorack-modified)	Make Noise	3	45 HP	—	400 mA	—	—
Mult	After Later Audio	3	2 HP	29 mm	20 mA	20 mA	0 mA
uO_C (Black & Gold Panel)	After Later Audio	3	8 HP	20 mm	85 mA	10 mA	0 mA
uT_u	After Later Audio	3	8 HP	20 mm	85 mA	10 mA	—
Elements (Black Panel)	Mörk Modules	3	34 HP	25 mm	130 mA	10 mA	0 mA
Black Joystick2	Erica Synths	3	12 HP	30 mm	71 mA	20 mA	0 mA
Disting mk4	Expert Sleepers	3	4 HP	42 mm	51 mA	19 mA	0 mA
Pique (uPeaks, micro)	After Later Audio	3	4 HP	15 mm	80 mA	1 mA	—

("—" marks a spec not recorded in the source data sheet, not a value of zero.)

What this demonstrates

Beyond the musical result, building this instrument required the same discipline as any constrained hardware system: allocating a fixed physical and electrical budget (HP per row, current per DC rail) across competing modules, choosing deliberate redundancy where it matters (two percussion-envelope generators, two modal-synthesis voices, for timbral range rather than backup), and designing a signal path — clock → quantization → sound source → processing → mix — that stays coherent even when the actual performance is entirely improvised.