Citadel Alchemist is a patchable hybrid-synthesis based eurorack module that empowers you in discovering melodies and even harmonies despite being monophonic.
Patch programmable sequencing via the control signals into the two PITCH MOD inputs opens up a world of melodic inspiration beyond classic arpeggios while staying in your preferred SCALE.

5 synthesis modes

The Alchemist has a carefully tuned wide timbral range spanning across 5 synthesis modes (FILTER, FM, HYPERSINE, SUPERSAW and GLITCHNOISE) accessed by main TIMBRE sweep that is refined by the RATIO control.

• The ENV macro knob affects different parts of the synth and sequencing engine to maximize musicality and it even lets you continually morph between the synthesis modes and access truly unique sounds.
• The timbral palette is further extended by the dual FX section which offers either a wide delay that will smear the arpeggios into echoed harmonies or a chorus-flanger-distortion-combfilter macro custom tuned for each synth mode.
• You can also access gliding rubber textures with the PITCH SLIDE macro that applies pitch envelope and portamento.
• You can customize its rhythms and scales with the web-based editor.

Modulate anything

All main parameters can be modulated and tightly sequenced by the surprisingly powerful CV and GATE pattern generator. Create groovy off-grid beats using the built-in LFO, which can be synced, reset, or left to run freely.

Midi Inside Out

Citadel Alchemist is not just a sound box—it’s a powerful MIDI controller and sequencer when connected via the USB port on the back of the module. Send finely curated USB MIDI data to your DAW or USB MIDI device, and discover new ways of playing and interacting through a modular interface. Citadel Alchemist receives TRS MIDI via front panel and both sends and receives USB MIDI via the connector on the back of the module.

Make it fun

Do not write melodies! Let them emerge from the behavior you set-up by the patch interaction of various modulation sources.

From Kastle to Citadel

CITADEL is a Eurorack reimagination of the popular Kastle 2 semi-modular desktop device. The CITADEL comes with a full 3.5mm patch bay that offers the flexibility needed in the eurorack format while maintaining the strengths of the Kastle 2 allowing it to stand on its own, and yet let it truly shine when patched with other modules. We’ve also added switches for hands-on control of the pattern generator.

The Citadel provides the basic infrastructure needed to integrate eurorack systems within the context of electronic music making: headphone output, TRS MIDI input and sync, tempo generator with divider/multiplier, USB MIDI (from the back of the module), stereo mixing, integrated LFO and Pattern generator and effects.

All that makes Citadel the perfect module for smaller and beginner systems while the fun and unique creativity of the Kastle 2 firmwares: the FX WIZARD multi-effect processor and WAVE BARD sample player will earn its place in larger setups.

Features

• 5 synth modes
  — FILTER
  — FM
  — SUPERSAW
  — HYPERSINE
  — GLITCHNOISE
  
  
• Hybrid synthesis
  — 4 oscillators
  — FM with feedback
  — Raw Waveform mixing
  — Ring mod
  — Track and hold
  — Stereo noise with track and hold
  — Stereo Filter
  — Transient shaper
  
  
• Dual FX section
  — Delay to the left
  — Chorus/Flanger/Distortion to the right
  
  
• stereo audio processing at 44kHz/16-bits
  
  
• PITCH knob with range of ± 3 octaves from base note
• PITCH MOD attenuverter knob for modulating pitch
  — NOTE input: quantized pitch with selectable scales (updates on trigger)
  — ►PLAY input: 3rd, 5th and octave above NOTE - triggers envelope on change, time quantized to PLAY GRID - great for arpeggios!
  — user-defined scales via web-based editor
  — BANK+PITCH MOD to change quantizer scale
  — BANK+TIMBRE MOD for root note adjustment
  — BANK+LFO MOD for fine tuning
  — BANK+PITCH to change and preview octave
  
  
• TIMBRE knob for main timbral sweep
  — refine TIMBRE sweep with RATIO (oscillator detune ratios and wave mixing ratios)
  — hit the SHIFT button to trigger the sound
  — TRIGGER input to trigger sound
  — TIMBRE MOD input with attenuversion
  
  
• MODE input with attenuation to change synth MODE with CV
  
  
• ENV knob
  — turn right to set decay and focuses TIMBRE on transients
  — turn left to reverse add attack and decay and focuses TIMBRE on BODY
  — fully left and right enters DRONE mode
  — slows down arpeggio at long envelopes
  — MODE MORPHING to the left
  — ENV MOD input with attenuverter
  — ENV MOD updates only at trigger
  — patchable ENV output of the envelope
  
  
• LFO with triangle and pulse output, reset input, attenuverting modulation, synced or free
• Tempo generator with tap tempo, divider, and external clock input
• Pattern generator (tempo synced) with GATE and CV output, patch-programmable
• GATE generator contains user-programmable RHYTHM patterns via web-based editor
  
  
• stereo eurorack-level DC coupled input with input gain (up to +6db), accepts up to -10V to + 10V
• input can be mixed at the output or run thru the built in effects
• DC coupled stereo eurorack-level output, -5V to +5V
• stereo headphone output capable of driving headphones up to 250 Ohm
• analog sync input
• analog sync output
  
  
• TRS MIDI Input (clock, notes, CCs, pitch bend)
• USB-C on the back of the module (firmware updates, USB MIDI in/out, uploading samples)

Technical Details

• 16 HP
• PTC fuse and diode protected 10 pin power connector
• 24 mm deep
• current consumption: +12 V: <60 mA (w/o headphones), <90 mA (w/headphones to max); -12 V: <20 mA
• Input Ranges:
  — PITCH: PLAY IN and NOTE IN: -0.2V to 7V
  — CLK IN, RESET IN, C IN, G IN: 0V to 5V
  — LFO MOD, MODE IN, TIMBRE IN, ENV MOD IN, LFO RESET, TRIG IN: -5V to +5V
  — L/R IN: -10V to +10V
• Output Ranges:
  — CLK OUT, ENV OUT, CV OUT, LFO TRI OUT, LFO PULSE OUT: 0V to +5V
  — L/R OUT: -5V to +5V
  — Headphone output: 2Vpp (line level compatible)

Web-based Editor

Use the Alchemist Laboratory to customize Citadel's rhythms and scales:
web-based editor.

DIY KIT

You can build your own Kastle 2 with our full DIY kit. Go through the complete assembly guide below and make sure that you understand all the steps.

• BUY DIY KIT
• Complete assembly guide pdf

Disclaimer:
We do not provide technical assistance or remote troubleshooting for DIY Kits. All PCB boards are fully tested before leaving our factory.
If you need help after assembly, we offer a paid repair service called Come to Daddy. Shipping costs are the customer’s responsibility.

Downloads

• quickstart guide pdf
  
  
• complete manual pdf
  
  
• calibration guide pdf
  
  
• latest firmware v1.5 zip
• how to update & release notes pdf
  
  
• Citadel panel change tool 3D print file
  
  
• press release pdf
• press kit drive

Audio

SOUNDCLOUND

Video