Dual Resonant High Pass / Low Pass Filter & Preamp Inspired by MS-20

The SHSL combines MS-20 style dual resonant filters with a Moogerfooger-inspired preamp. Both filters feature independent cutoff and resonance controls, with dedicated CV and expression inputs for voltage control. The preamp ranges from clean boost to saturated overdrive. Designed for guitar, bass, synthesizers, and drum machines, with seamless modular integration.

This is a dual resonant filter and preamp pedal. It features high-pass and low-pass resonant filters, inspired by classic synth circuits like the Korg MS-20.
It’s used to shape your guitar or bass signal dramatically. The resonant filters can create sweeping, vocal, or synth-like "wah" effects, and the preamp adds warmth and drive.
Great for guitarists, bassists, or synth players who want precise control over frequency sweeps, deep filter effects, or just a unique tone-shaping tool.

Two Fully Controllable High Pass and Low Pass Filters Arranged in Series :
Each filter has independent cutoff and resonance controls. When combined, these filters create a bandpass mode - a hallmark of classic MS-20 synth family that surpasses the limitations of switchable filter designs. Both filters self-oscillate when resonance exceeds the oscillation point, allowing the SHSL to function as a dual CV-controllable sine wave oscillator. The series arrangement provides maximum flexibility: use one filter alone, both in parallel frequency ranges, or create a swept bandpass by converging cutoff frequencies. This topology delivers everything from gentle resonant sweeps to aggressive filter screaming.

A Powerful Preamp for Saturation, Overdrive & Distortion :
SHSL has a dedicated preamp section which is inspired by Moogerfooger pedals providing beautiful coloring to the sound. The pre section can operate in array of modes from light saturation to pushing the amp into overdrive/distortion territory. Located before the filters, the preamp shapes your input signal before filtering, adding harmonic complexity and driving the filters harder for increased resonance and character. This arrangement mimics classic synthesizer signal flow where VCAs drive VCFs. The preamp transforms the SHSL from a transparent filter into a complete tone-shaping tool, adding weight to bass, grit to guitars, and warmth to digital synths.

CV and Expression Controls for Each Filter :
Separate CV and expression inputs for each filter provide complete dynamic control for live performances and effortless integration with modular systems. So High So Low can also be used as a standalone CV controllable synth / oscillator. CV inputs accept ±8V control voltage from sequencers, LFOs, envelope generators, or any modular source. Expression inputs allow standard expression pedals to control filter cutoff in real-time, functioning like a voltage-controlled wah pedal. This dual-control architecture enables complex modulation routing: sequence one filter while manually controlling the other, or use LFOs to create rhythmic filter pumping. The SHSL bridges guitar pedals and eurorack worlds without compromise.

FEATURES :

High Pass & Low Pass Filters
High Pass and Low Pass resonant filters inspired by MS-20 with separate cutoff and resonance controls. Filters are arranged in series and have controllable resonance. Past the oscillation point each filter begins to self oscillate and can be used as a CV controlled oscillator.
Preamp
SHSL has a dedicated preamp section which is inspired by Moogerfooger pedals providing the beautiful colouring to the sound. The pre section can operate in array of modes from light saturation to pushing the amp into overdrive/distortion territory.
CV & EXP controls
Separate CV inputs for each filter allow to control the pedal with the external controllers like Korg SQ-1 or Arturia devices. You can also sync it with your modular or semi modular system. Separate expression inputs for each filter allow controlling the SHSL with the expression pedal.

CONTROLS :

Master_ : Sets the overall output volume.
Preamp/Saturation : Rotate clockwise to add gain from the preamp section, which produces a darker, full-bodied, and saturated sound.
High Pass : Rotate clockwise to strengthen the high pass. As you turn the knob to the right, fewer low frequencies will remain, allowing only the high frequencies to pass through the filter.
Low Pass : Rotate counterclockwise to enhance the low pass. As you turn the knob to the left, fewer high frequencies will remain, allowing only the low frequencies to pass through the filter.
Resonance High : Sets the amount of amplification for the high frequencies around the cutoff point of the high pass filter. Increase the amplification by rotating the knob clockwise. The filter will begin to oscillate beyond the OSC Point.
Resonance Low : Sets the amount of amplification for the low frequencies around the cutoff point of the low pass filter. Increase the amplification by rotating the knob clockwise. The filter will start to oscillate beyond the OSC Point.

https://www.analogmusic.company/shsl