Morgasmatron

Intellijel 20HP
VCF FILTER VCA DISTORTION EFFECTS

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Dual 6-mode self-oscillating multimode VCF (LP2/LP1/BP1/HP1/HP2/BR1) with series/parallel routing, built-in crossfader, Q-drive soft saturation, ProCo Rat-style overdrive on Filter A and phase-invert ring modulation. MS-20-inspired Korgasmatron lineage.

Patch Ideas · 9

Duophonic sine voices
Filter A Q max · 1V/OCT from sequencer A · OUT A · Filter B Q max · 1V/OCT from sequencer B (breaks normal) · OUT B · two pitched sines with independent tuning — CUTOFF knobs act as coarse tune
▸ Show diagram
Patch diagramPatch diagram with 4 modules and 4 connections. Modules: Morgasmatron, Sequencer A, Sequencer B, Mixer. Signals: 2 audio, 2 pitch.MorgasmatronSequencer ASequencer BMixerFilter A: Q max · CUTOFF ≈ C3Filter B: Q max · CUTOFF ≈ C41V/OCT A1v/oct1V/OCT B1v/octOUT AaudioOUT BaudioPitch1v/octPitch1v/octLaudioRaudioaudiopitch
★ Self-osc kick
Filter A Q max · trigger → short AD → FM2 A (attenuverter positive) for pitch thump · second short AD → VCA after OUT A for amp · Q-Drive cranked for squarer attack · fat self-oscillated kick
▸ Show diagram
Patch diagramPatch diagram with 6 modules and 6 connections. Modules: Morgasmatron, ENV A, ENV B, Sequencer, VCA, Output. Signals: 2 audio, 2 cv, 2 trigger.MorgasmatronENV AENV BSequencerVCAOutputFilter A: Q max · Q-Drive high · LP2FM2 AcvOUT AaudioTrigtrigOutcvTrigtrigOutcvTrigtrigInaudioCVcvOutaudioInaudioaudiocvtrigger
★ 4-pole stacked LP
Both filters LP2 · Series ON · same CUTOFF, same Q · CV to FM2 A normals to B · single envelope opens both simultaneously — steep 4-pole slope with extra squelch from cascaded resonance
▸ Show diagram
Patch diagramPatch diagram with 4 modules and 3 connections. Modules: Morgasmatron, VCO, ENV, Output. Signals: 2 audio, 1 cv.MorgasmatronVCOENVOutputSeries ON: Filter A: LP2 · Filter B: LP2FM2 attenuverters: matchedIN AaudioFM2 AcvOUT BaudioOutaudioOutcvInaudio11. normals to FM2 Baudiocv
Contrary motion notch/bandpass
Filter A BR1 · Filter B BP1 · Parallel · same LFO → FM2 A positive · FM2 B attenuverter inverted · as notch rises, bandpass descends · MIX sweeps between hollow and focused timbres
▸ Show diagram
Patch diagramPatch diagram with 4 modules and 4 connections. Modules: Morgasmatron, VCO, LFO, Output. Signals: 3 audio, 1 cv.MorgasmatronVCOLFOOutputParallel · Filter A: BR1 · Filter B: BP1FM2 A: +atten · FM2 B: -atten (inverted)IN AaudioIN BaudioFM2 AcvMIXaudioOutaudioOutcvInaudio11. normals to FM2 B invertedaudiocv
Rat-overdrive synth lead
Saw VCO → IN A · Filter A LP2 · OVERDRIVE ON · Series · Filter B HP1 to tame bass · envelope → FM2 A with positive attenuation · modulate B's cutoff by hand for live tone sculpting over aggressive distortion
▸ Show diagram
Patch diagramPatch diagram with 4 modules and 3 connections. Modules: Morgasmatron, VCO, ENV, Output. Signals: 2 audio, 1 cv.MorgasmatronVCOENVOutputSeries · OVERDRIVE A: ONFilter A: LP2 · Filter B: HP1IN AaudioFM2 AcvOUT BaudioSawaudioOutcvInaudioaudiocv
Ring-mod voice
Carrier osc → IN A · modulator osc → XFADE CV · Parallel · both DRY switches up · PHASE INVERT ON · XFADE knob noon to null · clangorous ring modulation at MIX
▸ Show diagram
Patch diagramPatch diagram with 4 modules and 3 connections. Modules: Morgasmatron, VCO 1, VCO 2, Output. Signals: 2 audio, 1 cv.MorgasmatronVCO 1VCO 2OutputParallel · DRY A: ON · DRY B: ONPHASE INVERT: ON · XFADE: noonIN AaudioXFADE CVcvMIXaudioSawaudioSinecvInaudioaudiocv
★ Wet/dry parallel distortion
Bass VCO → IN A · IN B same source · Parallel · OVERDRIVE A ON · DRY B ON · XFADE = wet/dry blend · keeps bass weight while adding grit
▸ Show diagram
Patch diagramPatch diagram with 4 modules and 4 connections. Modules: Morgasmatron, VCO, Mult, Output. Signals: 4 audio.MorgasmatronVCOMultOutputParallel · OVERDRIVE A: ON · DRY B: ONFilter A: LP2 · cutoff openIN AaudioIN BaudioMIXaudioOutaudioInaudio1audio2audioInaudio11. XFADE = distortion amountaudio
Formant vocalizer
Parallel · both BP1 · cutoffs set to two vowel formants (e.g., 800Hz + 1200Hz for 'ah') · slow LFO >> FM2 A only (no normal to B) for animated vowel morph · XFADE noon
▸ Show diagram
Patch diagramPatch diagram with 4 modules and 4 connections. Modules: Morgasmatron, VCO, LFO, Output. Signals: 3 audio, 1 cv.MorgasmatronVCOLFOOutputParallel · Filter A: BP1 · Filter B: BP1Cutoffs: formant pairIN AaudioIN BaudioFM2 AcvMIXaudioSawaudioOutcvInaudio11. vowel morph on A onlyaudiocv
Send-FX with XFADE wet/dry
Drum mix → IN A · Parallel · heavy Q + OVERDRIVE on A · DRY B on · XFADE CV from slow LFO >> wet/dry breathing · dynamic FX send effect
▸ Show diagram
Patch diagramPatch diagram with 4 modules and 4 connections. Modules: Morgasmatron, LFO, Drums, Output. Signals: 3 audio, 1 cv.MorgasmatronLFODrumsOutputParallel · OVERDRIVE A: ON · DRY B: ONFilter A: BP1 · high QIN AaudioIN BaudioXFADE CVcvMIXaudioOutcvOutaudioInaudioaudiocv

Behaviors

Six filter modes MODE knob per filter

LP2 (2-pole low), LP1 (1-pole low), BP1 (1-pole band), HP1 (1-pole high), HP2 (2-pole high), BR1 (notch/band-reject). Modes are instant-switchable — makes live timbre morphs easy.

Dual sine oscillator Q at max, IN unpatched, 1V/OCT patched

Each filter self-oscillates at max Q, producing a pitched sine that tracks 1V/oct. Two independent pitched sines — useable as a full duophonic VCO pair.

Q-Drive squaring self-oscillate + crank Q-Drive

Q-Drive soft-clips the resonant sine, adding harmonics and gradually squaring the waveform. Fattens self-oscillation from pure sine toward reed/brass territory without breaking tracking.

Series cutoff stacking SERIES/PARALLEL up

A's output → B's input. Two same-mode filters in series steepen the slope (e.g., LP2 + LP2 = 4-pole). Mixed modes create formant-like peaks when cutoffs sit close.

Overdrive tone-control chain OVERDRIVE ON · Series mode · Filter B as tone

Filter A distorts aggressively; Filter B becomes a tone control sculpting the saturated signal. Modulating B's cutoff under performance control adds dynamic distortion tone.

Ring modulation via phase null Parallel · DRY both · PHASE INVERT ON · XFADE noon · XFADE CV drives modulation

With the two filter paths bypassed and Filter B phase-inverted, the XFADE knob nulls the signal. CV at XFADE CV jack multiplies in — yields ring modulation at MIX.

Wet/dry distortion Parallel · DRY B ON · OVERDRIVE A ON

XFADE knob becomes a wet/dry blend between distorted Filter A and untouched Filter B input. Parallel saturation without losing low-end clarity.

1V/OCT normal between filters leave B's 1V/OCT unpatched

A single pitch CV to Filter A's 1V/OCT tracks both filters (Filter B's jack normals from Filter A). Dummy-cable Filter B's 1V/OCT to break the normal for dual voices.

FM2 normal between filters leave B's FM2 unpatched

FM2 also normals A → B. One CV source can sweep both filter cutoffs simultaneously.

Controls

Filter A / Filter B CUTOFF Sets filter cutoff frequency. Sums with FM1 and FM2 CV inputs and the dedicated 1V/OCT input.
Full sweep · dedicated V/oct tracking
Filter A / Filter B FM1 Unipolar attenuator for FM1 CV input. FM1 tracks 1V/oct when fully CW.
0–unity · attenuator
Filter A / Filter B FM2 Bipolar attenuverter for FM2 CV. Noon = no effect · CW = positive · CCW = inverted.
Attenuverter · ±unity
Filter A / Filter B MODE Cycles through six filter modes: LP2, LP1, BP1, HP1, HP2, BR1 (notch).
Six-position select
Filter A / Filter B Q Sets resonance. Self-oscillates at maximum, producing a pitched sine that tracks 1V/OCT.
Sums with Q CV input · self-osc at max
Filter A / Filter B Q-DRIVE Drives resonance path to keep Q high as input gain rises. Adds warming growl at mid-Q and soft-clips self-oscillating sine into squarer wave at high Q.
Requires some Q to work · soft-clips sine
Filter A / Filter B IN Input gain. Unity at ~12 o'clock (10Vpp eurorack). Past noon induces soft clipping.
Unity at noon · soft-clip past noon
Filter A / Filter B OVERLOAD LED Lights when the filter output begins to soft-clip.
Red · per filter
Filter A OVERDRIVE switch Engages ProCo Rat-style aggressive overdrive circuit on Filter A's output. Up = on · down = clean.
A-only · pre-XFADE
Filter A → XFADE DRY switch A Up = bypass Filter A at XFADE (raw IN A feeds the crossfader). Enables wet/dry blends and parallel distortion tricks.
Up = dry · down = wet
Filter B → XFADE DRY switch B Up = bypass Filter B at XFADE (raw IN B feeds the crossfader).
Up = dry · down = wet
Filter B → XFADE PHASE INVERT Inverts Filter B's phase before XFADE. Enables ring modulation via phase cancellation and subtly different parallel colours.
Up = inverted
Filter A ↔ Filter B SERIES / PARALLEL switch Up = Series (A's output feeds B's input — steeper slope or tone-staging). Down = Parallel (both process inputs independently).
Two-position
MIX out XFADE Crossfades between Filter A and Filter B at the MIX output. Sums with XFADE CV.
CCW = A · CW = B · noon = equal
XFADE CV XFADE attenuverter Attenuates/inverts the XFADE CV input. Noon = no CV effect.
Bipolar
MIX out XFADE BALANCE LEDs Two LEDs (green) show Filter A and Filter B contribution to MIX in real time.
Dual LED

I/O

IN · 11

  • IN A 10Vpp typical AUDIO
    Audio input to Filter A
  • IN B 10Vpp typical AUDIO
    Audio input to Filter B
  • 1V/OCT (A) 1V/oct CV
    Dedicated pitch tracking CV for Filter A — tracks over several octaves at self-oscillation
    NORM → feeds Filter B's 1V/OCT when B is unpatched
  • 1V/OCT (B) 1V/oct CV
    Dedicated pitch tracking CV for Filter B
    NORM → Filter A's 1V/OCT when unpatched
  • FM1 (A) CV CV
    First cutoff CV for Filter A (attenuator)
  • FM1 (B) CV CV
    First cutoff CV for Filter B (attenuator)
  • FM2 (A) CV CV
    Second cutoff CV for Filter A (attenuverter)
    NORM → feeds B's FM2 when B unpatched
  • FM2 (B) CV CV
    Second cutoff CV for Filter B (attenuverter)
    NORM → Filter A's FM2 when unpatched
  • Q (A) CV CV
    CV for Filter A resonance (external attenuator recommended)
  • Q (B) CV CV
    CV for Filter B resonance
  • XFADE CV CV CV
    CV for crossfader — scaled by XFADE attenuverter

OUT · 3

  • OUT A 10Vpp
    Filter A direct output (post-overdrive if switched on)
  • OUT B 10Vpp
    Filter B direct output
  • MIX 10Vpp
    Crossfaded A/B mix with DRY switches and PHASE INVERT applied