Michael Claessens & Steve’s MS-22

A while ago I made an interesting little demo video with Michael Claessens, a talented Belgian Harmonica player. We combined his digital harmonica with my modular synthesizer with a patch featuring Steve’s MS-22. I think this really turned out spectacular. Have a look!

Michael Claessens is a Belgian harmonica player who’s interested in electronic music. We hooked up his digital harmonica to my modular system, featuring Steve’s MS-22 dual VCF. This lead to an evening of modular fun, including this funky jazz improv we taped…

Here are some patch notes:

  • Michael is playing a Lekholm DM48 Digital Chromatic Harmonica (https://www.lekholminstruments.com/).
  • We connected the DM48 to the Endorphin.es Shuttle Control over USB host.
  • We use two slightly detuned saw oscillators from the Intellijel Atlantis, which are mixed at 50% each and then sent into the input of Steve’s MS-22 dual VCF.
  • The DM48’s breath MIDI CC is converted to a smoothed unipolar CV and routed in to the MS-22’s FCV jack, modulating the cut-off frequency of the low-pass filter.
  • The MS-22 is set with a high gain and moderate resonance.
  • The high-pass filter is set at a low frequency, not affecting the signal.
  • The output of Steve’s MS-22 is then sent into a Zlob VniCursal VCA, modulated by the envelope of the Atlantis (triggered by the Shuttle Control).
  • Reverb was added by means of the Tip Top Z-DSP with the Valhalla Reverb card.

Steve’s MS-22 specifications released

As the rev. 2 prototype of Steve’s MS-22 is nearing its final form, I am happy to release its specifications :

  • General features
    • Dual VCF inspired by the Korg MS-20 OTA filter
    • Low-pass into high-pass 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

See the block schematic below (symbols as suggested by Bjørn & Meyers in “Patch & Tweak”)

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

I am currently working towards a demo video and hope I’ll be able to share that soon.

Subscribe to my mailing list and I’ll keep you posted about the development of this module and when it becomes available.

Getting ready to assemble Steve’s MS-22

I have received new and revised prototype PCB’s for Steve’s MS-22. Next week, I am planning to assemble these in between going to see Gregory Porter at Gent Jazz and Neil Young at the Sportpaleis in Antwerp (good times ahead!). In addition to the PCB’s, I also had new front panels manufactured in a sleek matte black finish. In the picture below you can get an impression of what the final product will look like. Stay tuned!

Meng Qi Karp / DU-KRPLS trigger input fix

A while back Marc Debroey (SEBASTOPOLmusic) asked me to take a look at his Meng Qi Karp, which didn’t trigger well. It was only after I fixed the problem that I discovered that it’s a known issue. However, the solution suggested by Meng Qi stops the trigger LED from working. In this post I will discuss what causes this issue, and share how to fix it without sacrificing the trigger LED.

Continue reading “Meng Qi Karp / DU-KRPLS trigger input fix”