Steve’s MS-22 dual VCF

A dual voltage controlled filter (inspired upon a classic OTA design) with an innovative modulation matrix and one of the highest function-to-hp ratios in the land of Eurorack. This module was inspired by many pleasant chats with tech journalist Steve O’Hear and is currently being prepared for release. Have a look below at the pictures, demos, specifications and block schematic!

Pictures

Notice : the final unit will have all black knobs!

Demo videos

The chaotic resonance of the HPF and LPF clashing is an excellent ingredient for dystopian drones and unique percussive pings!
Demo video focussing on envelopes and sub oscillator being sent into the modulation inputs.
Short demo video wherein the MS-22’s cutoff is being sequenced.
Hear the MS-22 on drums and learn how to perform an awesome “drop” with the filter’s link switch.
Ever wondered if a modular synth can be controlled through a harmonica?

Audio demo’s

The following audio demos are courtesy of Mr. Steve O’Hear!

Teasers

Specifications

  • General features
    • Dual VCF inspired by the Korg MS-20 OTA filter
    • Low-pass (12dB) into high-pass (6dB) configuration
    • Innovative modulation matrix allows CV control over all parameters
    • Cut-off frequencies can be linked, resulting in a band pass filter with controlable bandwidth
    • Bipolar monitoring LEDS for the LP, HP, resonance and gain CV signals
    • One of the best functionality-to-size ratios in Eurorack with a width of 4 HP and a depth of 45 mm
  • Connections
    • Filter input
    • Filter output
    • Frequency CV input (FCV)
    • Auxiliary CV input (ACV)
  • Controls
    • LP cut-off frequency (“frequency”)
    • HP cut-off frequency / BP bandwidth (“spread”)
    • Resonance : from mild to screamy
    • Gain : from warm to asymmetrical saturation
    • LP Frequency CV (FCV) attenuator
    • Auxiliary CV (ACV) attenuator
    • LP-HP link switch : 0%, 50% or 100%
    • Modulation Matrix switches, routing ACV to HP cut-off / spread, Gain and resonance : +ACV, off, or -ACV (inverted)
    • Calibration trimmers for the HP and LP filter are available from the side of the module.
  • Modulation
    • Designed to work with unipolar +5V or bipolar +-5V modulation sources
    • Will also take unipolar and bipolar 8 and 10V modulation signals, but this results in a smaller usable range on the ACV and FCV attenuators
    • Low frequency and audio rate modulation of all parameters
    • Bipolar monitoring LEDs (green: positive, red: negative) for all CV destinations (LP cut-off, HP cut-off / spread, resonance, gain)
  • Construction
    • 4 HP wide
    • 45 mm deep (skiff friendly)
    • High quality aluminum knobs with grippy surface
    • 2 mm thick matte black front panel with white and metallic print
    • A tasty 4-layer PCB sandwich, containing 350+ components
    • Recessed power connector, avoids your power cable from adding to the module depth
  • Protection
    • Reverse power protection
    • Buffered high impedance inputs
    • Output is protected by a 1K output resistor
  • Power consumption
    • +12V : 100mA max
    • -12V : 100mA max

Block schematic

Steve’s MS-22 filter topology
Steve’s MS-22 modulation matrix

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