Citadel Alchemist

Bastl Instruments 16HP

Patchable hybrid-synthesis voice with MIDI, tempo-synced pattern generation, dual FX and stereo I/O. Monophonic but heavily modulatable, it doubles as a voice, rhythm source and MIDI bridge.

Patch Ideas · 5

Scale-locked arp lead
NOTE IN takes the melody · PLAY IN advances the upper arpeggio voice · CLK IN locks the rhythm · TIMBRE at noon and RATIO slightly detuned produce a moving but still coherent lead · L/R OUT goes straight to the main output.
Show diagram
Patch diagramPatch diagram with 4 modules and 4 connections. Modules: Citadel Alchemist, Sequencer, Clock, Output. Signals: 1 audio, 1 pitch, 1 gate, 1 clock.Citadel AlchemistSequencerClockOutputMODE: FILTERTIMBRE: noonRATIO: slight detuneENV: mediumNOTE IN1v/octCLK INclkPLAY INgateL/R OUTaudioPitch1v/octGategateOutclkInaudioaudiopitchgateclock
Mode-morph drone
MODE CV moves between synthesis types · LFO into TIMBRE MOD and ENV MOD keeps the sound alive without constant re-patching · leave PLAY IN untriggered for long-held tones and slow harmonic drift.
Show diagram
Patch diagramPatch diagram with 4 modules and 3 connections. Modules: Citadel Alchemist, LFO, Envelope, Output. Signals: 1 audio, 2 cv.Citadel AlchemistLFOEnvelopeOutputMODE: FMENV: longLFO: synced slowTIMBRE MODcvENV MODcvL/R OUTaudioOutcvOutcvInaudioaudiocv
Clocked gate machine
CLK IN drives the internal tempo generator · CV OUT and CLK OUT feed external drums and envelopes · use SHIFT and TAP TEMPO to re-center the feel while the module stays locked to the rack clock.
Show diagram
Patch diagramPatch diagram with 5 modules and 5 connections. Modules: Citadel Alchemist, Drum, Envelope, Clock, Output. Signals: 1 audio, 2 cv, 1 trigger, 1 clock.Citadel AlchemistDrumEnvelopeClockOutputMODE: GLITCHNOISEENV: shortCLK INclkCV OUTcvCLK OUTtrigENV OUTcvAccentcvTrigtrigOutaudioTrigcvOutclkInaudioaudiocvtriggerclock
Stereo FX insert
Audio into L/R IN runs through the internal dual FX block · set TIMBRE low and ENV medium for a wider, slower-moving smear · L/R OUT returns the processed signal as a stereo insert point.
Show diagram
Patch diagramPatch diagram with 3 modules and 4 connections. Modules: Citadel Alchemist, Audio Source, Output. Signals: 4 audio.Citadel AlchemistAudio SourceOutputMODE: FILTERTIMBRE: lowENV: mediumL/R INaudioL/R OUTaudioLaudioRaudioLaudioRaudioaudio
MIDI bridge voice
USB-C on the rear bridges a DAW or controller into the module while the front panel stays fully patchable · use the pattern generator to sequence the voice and export the result as stereo audio or CV for the rest of the rack.
Show diagram
Patch diagramPatch diagram with 4 modules and 3 connections. Modules: Citadel Alchemist, Computer, Output, Filter. Signals: 1 audio, 2 cv.Citadel AlchemistComputerOutputFilterMODE: SUPERSAWENV: mediumUSB-CcvCV OUTcvL/R OUTaudioUSB MIDIcvInaudioCutoffcvaudiocv

Behaviors

Five-mode synth voice turn TIMBRE or change MODE

The voice moves through FILTER, FM, HYPERSINE, SUPERSAW and GLITCHNOISE while the ratio and envelope macros reshape how the mode behaves.

Scale-locked note updates patch NOTE IN or PLAY IN

The internal quantizer holds the current scale, updates notes on trigger and can preview octave and root changes through bank combinations.

Pattern generator with CV and gate use the sequencer engine

The built-in pattern engine generates CV and gate streams that can be synced, reset and customized from the web editor.

LFO-driven groove drift use the internal LFO

The LFO can sync to clock, reset to phase zero or free-run, which makes the module behave like a small self-contained groove engine.

Stereo FX split feed stereo audio into L/R IN

The module can process external stereo audio through its dual effects section and return it as a stereo voice or modulation source.

USB and TRS MIDI bridge connect MIDI to TRS or USB-C

The module receives clock and notes over TRS MIDI and sends or receives USB MIDI on the rear connector.

Controls

Voice PITCH Sets the core pitch in a ±3 octave range from the base note.
macro knob
Voice PITCH MOD Attenuverts incoming pitch modulation.
attenuverter
Voice TIMBRE Sweeps the sound engine across the five synthesis modes.
FILTER · FM · HYPERSINE · SUPERSAW · GLITCHNOISE
Voice TIMBRE MOD Modulates timbre with bipolar depth control.
attenuverted CV
Voice RATIO Sets oscillator detune ratios and waveform blend relationships.
macro knob
Voice ENV Shapes the envelope behavior and pushes the sound toward drone, body or transient focus.
macro knob
Voice ENV MOD Attenuverted envelope modulation input.
updates on trigger
LFO LFO FREQUENCY Sets the built-in LFO rate.
syncable or free-running
LFO LFO MOD Sets depth and polarity for LFO modulation.
attenuverter
Voice MODE Selects the synthesis mode or morph target.
CV-capable
Global SHIFT Secondary action button for triggering and alternate panel functions.
momentary
Clock TAP TEMPO Sets the internal tempo generator.
tap-tempo

I/O

IN · 15

  • NOTE IN -0.2V to 7V GATE
    Quantized pitch input; updates on trigger and follows the selected scale.
  • PLAY IN 3V+ trigger GATE
    Quantized pitch trigger input for the arpeggio-style upper voices.
  • PITCH MOD -5V to +5V CV
    Pitch modulation input with attenuverter.
  • TIMBRE MOD -5V to +5V
    Modulates the timbre sweep.
  • MODE IN -5V to +5V CV
    CV-selects or morphs the synthesis mode.
  • ENV MOD -5V to +5V ENV
    Modulates the envelope macro.
  • LFO RESET 0V to 5V
    Resets the internal LFO phase.
  • CLK IN 0V to 5V CLK
    External tempo clock input.
  • RESET IN 0V to 5V
    Resets the internal pattern generator.
  • C IN -5V to +5V
    Auxiliary control input for the pattern engine.
  • G IN 0V to 5V GATE
    Auxiliary gate input for the pattern engine.
  • TRIGGER IN 0V to 5V GATE
    Triggers the sound engine.
  • L/R IN -10V to +10V AUDIO
    Stereo audio input for processing through the internal mixer and effects.
  • TRS MIDI IN MIDI CLK
    Front-panel TRS MIDI input for clock, notes, CC and pitch bend.
  • USB-C USB
    Rear USB-C port for firmware updates, USB MIDI in/out and sample upload.

OUT · 8

  • CLK OUT 0V to 5V CLK
    Tempo output from the internal clock generator.
  • ENV OUT 0V to 5V ENV
    Patchable envelope output.
  • CV OUT 0V to 5V GATE
    Gate-pattern CV output from the sequencer engine.
  • LFO TRI OUT 0V to 5V
    Triangle LFO output.
  • LFO PULSE OUT 0V to 5V GATE
    Pulse LFO output.
  • L/R OUT -5V to +5V AUDIO
    Stereo DC-coupled audio output.
  • HEADPHONE OUT 2Vpp
    Front-panel headphone output.
  • SYNC OUT 0V to 5V
    Analog sync output.