Six modules for VCV Rack 2.x by Javier Melgar (Animatek).
- UZZ — Ultimate Ztep Zequencer: a 16-step sequencer with per-row shift, probability, accumulator, and flexible clock.
- ONE — 6HP MIDI-to-CV interface designed for the Oxi One controller.
- MULTI — 10HP expander for ONE with 8 configurable multi-track outputs.
- APC40 CTRL — 13HP MIDI-to-CV bridge for the Akai APC40, with all knobs, faders and the master fader on a single panel.
- UNIT-D — deterministic polyphonic generative sequencer based on unit-distance graph walks. Manuals: EN / ES.
- BLANK 3 — 3HP blank panel with animated low-opacity Animatek logo pattern and global pause option.
UZZ is a step sequencer originally created as a Max for Live device, designed for immediate control, clear visual feedback, and fluid musical flow.
This repository is a port to VCV Rack 2.x, aiming to preserve the original philosophy: precise timing, structured improvisation, and modular flexibility.
- 16 steps with per-step Pitch, Octave, tempo-relative Duration, Mod1, Mod2, and bipolar Prob/Pulse
- Per-step step mode: Play, Mute, Skip, Accum Up, Accum Down, Pulse, Gated, Hold
- Active window: configurable Start and Step count with wrap-around
- Clock ratios: ÷8 to ×8 and beyond, with swing
- Direction modes: Forward, Backward, Pendulum, Ping-Pong, Random, Drunk, Odd/Even, Jump, Converge, Diverge
- Global glide (slew) on pitch output
- Accumulator: semitone offset that accumulates on ACCUM steps, with wrap control
- Per-row Randomize buttons with CV trig inputs (Pitch, Oct, Mode, Dur, Mod1, Mod2, Prob)
- Per-row Shift up/down arrows for all rows including Prob/Pulse
- Per-step Prob/Pulse knob: probability on the left side, pulse multiplier on the right side
- Global Probability knob — multiplicative on gate triggering
- Polyphonic step-gate output (one channel per active step)
- EOC output, transpose input, reset input
A 6HP MIDI-to-CV converter designed for the Oxi One sequencer/controller, covering all its output modes.
- V/Oct, Gate, Velocity outputs
- 8× CC outputs (configurable CC numbers per slot)
- Clock output and CLK/n divisions (÷1 to ÷32)
- Run output
- Supports Mono, Poly, Chord, Multitrack and Matriceal Oxi One modes
- Channel-selectable MIDI input (Omni or specific channel)
- Compact 6HP panel
A 10HP expander for ONE that unlocks its multi-track capabilities.
- 8 configurable tracks with independent V/Oct, Gate, and Velocity outputs
- Works alongside ONE in Multitrack and Matriceal modes
- Must be placed immediately to the right of ONE
- Mirrors the current ONE track configuration through the expander link
A 13HP MIDI-to-CV bridge that captures every continuous controller of the Akai APC40 MkI/MkII on a single panel. Designed to sit next to MULTI: title, header divider and the first knob share the same vertical position so both modules read as a pair.
- 8 Track Controls (T1–T8) on CC 48–55 with per-output attenuverters.
- 8 Device Knobs (D1–D8) on CC 16–23 with per-output attenuverters.
- CUE level (CC 47), MASTER fader (CC 14) and XFAD crossfader (CC 11), each with attenuverter.
- 8 Channel Faders (F1–F8) in a dedicated column on the right: all share CC 7 but on MIDI channels 1–8, so the eight faders of the APC40 reach Rack as eight independent CV outputs without remapping the controller.
- All knob/CC controls listen on MIDI channel 1; the fader column accepts channels 1–8 in parallel.
- 0 → 10 V output range. Use the per-control attenuverter to scale or invert as needed; faders pass through directly.
A compact deterministic generative sequencer based on unit-distance graph walks. UNIT-D creates a seeded 2D cloud of nodes, connects nodes that sit near a target distance, and turns the graph traversal into quantized pitch, gates, accents and related X/Y modulation. The same seed and settings always produce the same structure, so it can move between generative exploration and repeatable musical phrases. Manuals: EN / ES.
- Seeded graph generation with 8–64 nodes, unit radius, tolerance fine-tuning and musical density control.
- Deterministic walker with selectable Walk mode, resettable state and repeatable behaviour for saved patches.
- Bipolar LOCK control for gradual 16 / 32-step phrase capture, including forward and reverse lock directions.
- Quantized minor-scale V/oct output with selectable 1–4 octave range.
- Tempo-following Gate output with gate length and gate-density controls.
- Related Accent, X CV and Y CV outputs derived from graph degree and node position.
- Polyphonic operation from the context menu: 1–8 voices, with shared seed or per-voice seed graphs.
- Inputs: Clock, Reset, Seed CV and Density CV.
- Outputs: V/oct, Gate, Accent, X CV and Y CV.
- Panel theme menu (Dark / Light).
A 3HP blank panel for filling small gaps in a Rack patch while keeping the Animatek visual language.
- 3HP utility blank with dark / light panel artwork.
- Subtle animated background pattern using the Animatek logo.
- Context-menu Pause animation option.
- Panel theme menu (Dark / Light).
(2026-05)
- Added UNIT-D, a compact deterministic polyphonic generative sequencer based on unit-distance graph walks.
- Seeded 2D nodes create graph transitions with controls for node count, radius, density, tolerance, walk mode, range, gate length, gate density and lock.
- Outputs include quantized V/O, GATE, ACC, X CV and Y CV for linked melody, gates, accents and modulation.
- Added expanded manuals in English and Spanish:
Manuals/UNIT-D_Manual_EN.mdandManuals/UNIT-D_Manual_ES.md.
- Added BLANK 3, a 3HP blank panel with Animatek branding.
- Background logos are generated per instance with randomized position, size, rotation and opacity.
- Logos drift with a very slow random walk by default.
- Added right-click Pause animation option, global across all BLANK 3 instances, to freeze animation and reduce idle work.
- Public display names changed from OXI-CV to ONE and from OXI-CV EXPANSOR to MULTI.
- Added bottom-panel module labels using the same blue label style as UZZ.
- Updated custom Animatek input/output port assets across the public modules.
(2026-05)
- 13HP MIDI-to-CV bridge for the Akai APC40 with the full continuous-controller surface on one panel: 8 track controls, 8 device knobs, Cue, Master and Crossfader (with attenuverters), plus a separate column of 8 channel faders that listen to CC 7 on MIDI channels 1–8 directly.
- Layout aligned with OXI-CV EXPANSOR so the two modules share title height, header divider position and first-knob row when placed side by side.
- Deleted
res/UZZ-overlay.svg/res/UZZ-overlay-light.svgand the unusedUzzStaticOverlaywidget. Older VCV versions could render the obsolete overlay on top of the current panel; the dead code path is now gone.
- New
BasicDisplaybase widget shared byParamDisplayandAccumDisplay— drops ~25 lines of duplicated background/font setup. - New
loadPluginSvgOr(plugin, fallback)helper used byRowShiftButtonandStepModeButtonto replace the hand-rolled load-with-fallback pattern. - The five identical 16-step
UzzArcKnobloops inUZZWidgetcollapsed into a singleaddArcKnobRow(y, paramBase)lambda. - Hardcoded display blue replaced with the existing
displayBlue()helper fromCommonWidgets. - Dead
UZZ_USE_CODE_LABELSmacro and its always-true branch removed.
(2026-04)
- Added Panel → Light / Dark submenu to the right-click context menu of UZZ, OXI-CV and OXI-CV EXPANSOR.
- Toggles VCV Rack's global
preferDarkPanelssetting directly from the module, so the theme can be switched without opening Rack's global preferences.
- The per-step Prob/Pulse knob now applies probability on its left side (negative values) for Pulse, Gated and Hold steps too — previously these modes only honoured the global probability.
- Right side of the knob keeps its meaning: pulse count, always at 100 % probability per repetition.
- Fixed a case where the Gate output could stay high for several seconds (or indefinitely) when the upstream clock was held at 10 V or had been connected long before play started.
- Internal clock now ignores the first edge's accumulated time and rejects implausibly long periods (>5 s ≈ 12 BPM) instead of feeding them into the gate-length calculation.
- Schmitt trigger uses explicit
0.1 V / 2 Vthresholds (matching Fundamental SEQ3) for cleaner edge detection on signals that idle slightly above 0 V. - Added hard upper bounds: gate length capped at 2 s, Gated sustain capped at 8 s — even with pathological state the gate cannot stay open indefinitely.
(2026-04)
Kept as a Rack 2.x-compatible
2.xrelease so VCV Rack 2 loads the plugin.
- Added three per-step modes: Pulse, Gated, and Hold.
- Pulse generates ratcheted sub-gates inside the clock period.
- Gated can stretch one step across multiple clock periods.
- Hold can re-fire the current step across multiple incoming clocks before advancing.
- Added dedicated panel icons for the new step modes.
- The former Probability row is now Prob/Pulse.
- Knob center (
0) means normal playback: 100 % probability / ×1 pulse. - Turning left sets per-step probability from 100 % down to 0 %.
- Turning right sets pulse multiplication from ×2 to ×8.
- Randomize, Shift and Reset for the row were updated to the new bipolar behavior.
- For Play and Accum steps, the row acts as probability.
- For Pulse, Gated, and Hold steps, the left side still acts as per-step probability and the right side as pulse count (always 100 %).
- Added Pendulum, Odd/Even, Jump, Converge, and Diverge direction modes.
- Ping-Pong now exists as its own mode, distinct from Pendulum.
- Jump uses a configurable stride from the right-click context menu.
- Sequencer state now stores the advanced direction position so patches resume consistently.
- The Duration row is now tempo-relative duty, displayed as percent of the clock step instead of independent seconds.
- Gate length calculation was centralized to keep pulses and gated playback consistent across ratios.
- In Gate mode, ratcheted repeats now use the repeat interval as their timing window so each repeat has a clear low gap before the next gate.
- Ratchet sub-pulses are scheduled inside the audio process loop rather than treated as separate steps.
- Hold/gated states are cleared cleanly on hard stop and reset.
- Group guide lines now sit between steps 4/5, 8/9, and 12/13.
- Group guide lines use the Animatek logo blue with reduced opacity.
- The row label for the bipolar probability/pulse controls is shown as PROB to fit the panel.
(2026-04)
- Added ACCUM WRAP Trimpot (0–12 st) alongside the existing ACCUM AMT knob.
- When WRAP > 0, the accumulated pitch offset loops via modulo: e.g. WRAP=6 cycles the offset 0→1→2→3→4→5→0→... (50 % of an octave).
- WRAP=12 gives a full-octave cycle; WRAP=0 (default) preserves the original ±12 semitone behaviour.
- Works symmetrically for ACCUM UP and ACCUM DOWN.
- The AccumDisplay panel widget shows both values: semitone amount (top line) and wrap point or "OFF" (bottom line).
- Existing patches are unaffected (WRAP defaults to 0 = OFF).
- Slug comparisons in
process()replaced with model-pointer comparisons (avoidsstd::stringallocation at audio rate). noteToVoct()helper added toplugin.hpp, removing 3 duplicated inline expressions across OXI-CV and OXI-CV EXPANSOR.silenceAllVoices()extracted in OXI-CV, replacing two copy-paste blocks.fillRow()helper added to UZZ, simplifying 7reset*Row()methods.- Dead code removed: unused lambdas and constants.
(2026-04)
- Added PROB row: 16 Trimpot knobs (0–100 %, default 100 %) placed above the Pitch row, one per step.
- Added Global PROB knob in the bottom panel (bottom-right position, replaces old EOC slot).
- Probability is multiplicative:
p_final = p_step × p_global. Only the gate is silenced on failure; pitch, Mod1/Mod2 and accumulator continue unaffected. - Probability is evaluated on every step arrival using
random::uniform(). - Full row support: Randomize PROB button + CV trig input, Shift PROB up/down arrows (10 % per click), right-click Reset PROB to 100 %.
- New params appended at end of enum — existing patches default PROB to 100 % and play back unmodified.
- STEP_GATES (poly) output moved to the step 11 column (bottom row).
- EOC output moved to the step 13 column (bottom row).
- Global PROB knob placed at step 15 column (bottom row) with PROB label at step 14.
- All panel labels now use
APP->window->uiFont(Rack's system UI proportional font) rendered indrawLayer(1), matching the look of OXI-CV. - Fake-bold via 0.15 px horizontal pass, uppercase enforced at construction.
- Row labels (MODE, PITCH, OCT, DUR, MOD1, MOD2, PROB) repositioned above their trig input ports with consistent 3 px gap.
- OXI-CV: 6HP MIDI-to-CV for Oxi One — V/Oct, Gate, Velocity, 8× CC, Clock, CLK divisions, Run. Mono/Poly/Chord/Multitrack/Matriceal modes.
- OXI-CV EXPANSOR: 10HP expander — 8 configurable tracks with V/Oct, Gate, Velocity outputs.
(2025-11)
- Fixed critical crash when reloading the Rack plugin inside Bitwig or other hosts.
dataToJson()now creates its ownjson_object()when the base isnullptr.dataFromJson()calls the base method before applying stored values.- UI asset safety during headless scans — constructors guard against null
APP->window.
- Default clock ratio set to ×1.
- Virtual clock rewrite: internal oscillator only runs when ratio ≠ ×1.
havePhaseforced off at ×1 to prevent extra steps during held gates.
- Font loading uses
asset::system("res/fonts/ShareTechMono-Regular.ttf")withAPP && APP->windowguards. - Text rendering tuned: centered alignment, pixel-rounded coordinates, 9 px size.
- Unified safe SVG loader routing all assets through a single helper.
- Step-mode icons and row-shift arrows render correctly after VST project reloads.
(2025-10-03)
- Added per-row shift controls for Pitch, Octave, Duration, Mod1, and Mod2.
- Contextual menu: submenus for Direction mode, Range Mod1/Mod2, EOC-on-reset toggle.
- Implemented optional EOC trigger on external reset with persistence.
- Refined reset handling: active step fires before jumping to start window.
- Custom input/output port widgets (10 % scale reduction).
- Tuned slew to logarithmic curve.
(2025-09-23)
- Clock multipliers now trigger the first sub-tick correctly.
- Limited maximum multiplier to ×48.
- Old patches with ×64/×96 clamp to ×48 automatically.
Build against the VCV Rack 2 SDK:
RACK_DIR=/path/to/Rack-SDK makeInstall the plugin into your local Rack setup:
RACK_DIR=/path/to/Rack-SDK make installCreate a distributable package:
RACK_DIR=/path/to/Rack-SDK make dist- Website: https://animatek.net
- Manual: https://animatek.net/ultimate-ztep-zequencer-vcvrack/
- YouTube: https://www.youtube.com/@animatek
- Author: Javier Melgar (Animatek)
- License: GPL-3.0-or-later