Steve's MS-22

ThreeTom Modular 4HP
VCF FILTER WAVESHAPER

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MS-20-inspired dual VCF in 4 HP. 12 dB low-pass feeds 6 dB high-pass in series. Link switch couples both cutoffs for bandpass. Modulation matrix routes one aux CV to HP, gain or resonance with bipolar polarity.

Patch Ideas · 8

★ Classic MS-20 lead
Saw VCO into IN · FCV from envelope · RES past 3 o'clock · GAIN mid for bite · Link=0% for pure LP squelch
▸ Show diagram
Patch diagramPatch diagram with 4 modules and 3 connections. Modules: Steve's MS-22, Envelope, VCO, VCA. Signals: 2 audio, 1 cv.Steve's MS-22EnvelopeVCOVCALink: 0% · Res: 3 o'clock · Gain: noonINaudioFCVcvOUTaudioOutcvSawaudioInaudioaudiocv
★ Self-oscillating sine voice
No input · RES maxed · LP self-oscillates · sequencer into FCV tracks 1V/oct · sine voice in 4 HP · add drive via GAIN for overtones
▸ Show diagram
Patch diagramPatch diagram with 4 modules and 3 connections. Modules: Steve's MS-22, Sequencer, Envelope, VCA. Signals: 1 audio, 1 cv, 1 pitch.Steve's MS-22SequencerEnvelopeVCARes: max · Link: 0% · FCV attn: full CWFCV1v/octOUTaudioPitch1v/octOutcvCVcvInaudioaudiocvpitch
CV-swept bandpass wah
Link=100% · SPREAD sets narrow band · slow LFO into FCV sweeps the whole bandpass · guitar-through-eurorack wah
▸ Show diagram
Patch diagramPatch diagram with 4 modules and 3 connections. Modules: Steve's MS-22, LFO, Guitar, Output. Signals: 2 audio, 1 cv.Steve's MS-22LFOGuitarOutputLink: 100% · Spread: narrowINaudioFCVcvOUTaudioOutcvOutaudioInaudioaudiocv
Envelope → LP open / HP close
Matrix: HP=-ACV, GAIN=OFF, RES=OFF · envelope into ACV · same envelope into FCV · LP opens while HP closes → formant-like sweep with one EG
▸ Show diagram
Patch diagramPatch diagram with 4 modules and 4 connections. Modules: Steve's MS-22, Envelope, VCO, VCA. Signals: 2 audio, 2 cv.Steve's MS-22EnvelopeVCOVCALink: 0% · Matrix HP: -ACVINaudioFCVcvACVcvOUTaudioOutcvSawaudioInaudioaudiocv
★ Filter + VCA voice card
Matrix: GAIN=+ACV · envelope → ACV · GAIN doubles as VCA · saves one VCA module for a full voice in 4 HP
▸ Show diagram
Patch diagramPatch diagram with 5 modules and 4 connections. Modules: Steve's MS-22, Envelope, VCO, Keyboard, Output. Signals: 2 audio, 1 cv, 1 pitch.Steve's MS-22EnvelopeVCOKeyboardOutputMatrix Gain: +ACV · Res: 2 o'clockINaudioACVcvFCV1v/octOUTaudioOutcvSawaudioPitch1v/octInaudio11. acts as VCA CVaudiocvpitch
Resonance accents
Matrix: RES=+ACV · accent trigger → envelope → ACV · resonance jumps on accented steps · drum-machine style squelchy bass
▸ Show diagram
Patch diagramPatch diagram with 5 modules and 4 connections. Modules: Steve's MS-22, Accent EG, Sequencer, Sub VCO, Output. Signals: 2 audio, 1 cv, 1 pitch.Steve's MS-22Accent EGSequencerSub VCOOutputMatrix Res: +ACV · base Res: 1 o'clockINaudioFCV1v/octACVcvOUTaudioOutcvPitch1v/octSawaudioInaudioaudiocvpitch
Audio-rate screamer
Audio-rate sine into FCV · GAIN high · RES high · FM screams and drive clip mix for metallic industrial tones · Link=50% for spectral twist
▸ Show diagram
Patch diagramPatch diagram with 4 modules and 3 connections. Modules: Steve's MS-22, Modulator VCO, Carrier VCO, VCA. Signals: 2 audio, 1 cv.Steve's MS-22Modulator VCOCarrier VCOVCAGain: 3 o'clock · Res: max · Link: 50%INaudioFCVcvOUTaudioSinecvSawaudioInaudioaudiocv
Stereo split via matrix
Two identical patches through one MS-22 isn't stereo — but flipping matrix polarities (+/-ACV on HP vs RES) from one shared CV creates wide spectral movement · pan the result by patching dry IN to left and MS-22 OUT to right
▸ Show diagram
Patch diagramPatch diagram with 5 modules and 5 connections. Modules: Steve's MS-22, VCO, LFO, Mult, Output. Signals: 4 audio, 1 cv.Steve's MS-22VCOLFOMultOutputMatrix HP: +ACV · Matrix Res: -ACVINaudioACVcvOUTaudioSawaudioOutcvInaudioOut 1audioOut 2audioLaudioRaudioaudiocv

Behaviors

Serial LP→HP topology signal into IN

Audio passes through the 12 dB LP then the 6 dB HP. With Link=0% the two cutoffs are independent and you sculpt a bandpass by squeezing between them.

Linked bandpass Link switch → 50% / 100%

HP cutoff tracks LP cutoff at 50% or 100%. FREQUENCY sweeps both together; SPREAD offsets the HP relative to the LP, giving wide or narrow BP. FCV modulates the whole band.

Resonance self-oscillation RESONANCE → past ~3 o'clock

LP stage self-oscillates into a clean sine wave at cutoff. Track with FCV for a playable sine VCO. Thins bass as resonance rises — classic MS-20 behaviour.

GAIN as VCA ACV matrix → GAIN

Route an envelope to GAIN via the matrix. GAIN becomes a CV-controlled input level / overdrive, turning the module into filter+VCA voice-card in 4 HP.

Matrix polarity flip matrix switch → -ACV

Inverts ACV at that destination. Envelope opens LP but simultaneously closes HP, or vice versa, for sweeps that move in opposite directions from one CV source.

MS-20 drive character high GAIN

Discrete OTA core clips asymmetrically when driven. Adds even-order harmonics on transients. Pair with resonance for the characteristic MS-20 squelch.

Controls

LP stage FREQUENCY Low-pass cutoff. Covers sub to above audio range. Into self-oscillation when resonance is cranked, producing a sine at the cutoff.
12 dB/oct LP · self-oscillates at high resonance · tracks 1V/oct via FCV
HP stage SPREAD High-pass cutoff when Link=0%. In linked modes it becomes a bandwidth/offset control for the resulting bandpass response.
6 dB/oct HP · offset in BP modes · bandwidth set by Link position
LP stage RESONANCE Emphasis around LP cutoff. Pushed well past the MS-20 — from gentle to screaming self-oscillation. Thins bass when maxed.
mild to self-oscillation · past the MS-20's range · CV-able via matrix
Input stage GAIN Input drive into the LP stage. Low values stay warm; high values push into asymmetric saturation (MS-20-style overdrive). Functions as a VCA when CV'd via matrix.
warm → asymmetrical drive · doubles as VCA when under aux CV
FCV input FCV attenuator Attenuates the frequency CV input which tracks the LP cutoff. Set CCW for pure audio-rate listening; CW for full 1V/oct tracking.
±5V → full range · calibrated for 1V/oct when full CW
ACV input ACV attenuator Attenuates the auxiliary CV. Routed to HP/SPREAD, GAIN or RESONANCE via the matrix switches. Independent per destination.
±5V range · shared by all matrix destinations
Global LINK switch Three-way couples HP cutoff to LP cutoff. 0% = independent; 50% = wide bandpass; 100% = narrow bandpass tracking LP.
0% · 50% · 100% coupling · SPREAD becomes BP offset in linked modes
ACV routing Modulation matrix switches Three-position switches assign ACV polarity per destination (HP / GAIN / RES). Off, +ACV or -ACV (inverted). Internal patch without cables.
per destination: +ACV · OFF · -ACV · three independent switches

I/O

IN · 3

  • IN ±5V nominal · overdrives above AUDIO
    Audio input into the GAIN stage. Accepts Eurorack line levels; overdrive starts around halfway on GAIN.
  • FCV ±5V nominal · accepts ±10V CV
    Frequency CV input tracking the LP cutoff. Calibrated for 1V/oct when the attenuator is full CW.
  • ACV ±5V nominal · accepts ±10V CV
    Auxiliary CV input. Routed via the modulation matrix to any combination of HP/SPREAD, GAIN, RESONANCE with selectable polarity.

OUT · 1

  • OUT ±5V audio AUDIO
    Main filter output, taken after the HP stage. Produces LP, HP or BP depending on Link switch and SPREAD settings.