How Does It Work?#

MS-20 LPF is a Korg 35-inspired lowpass filter with Cutoff, Res, and Drive, aimed at sharp sweeps, hard resonance, and deliberately unruly tone shaping.

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Quick Overview#

• MS-20 LPF is a single-input, single-output lowpass filter.
• It combines a large Cutoff knob with smaller Res and Drive controls.
• The cutoff range is 20 Hz to 20000 Hz.
• Resonance ranges from 0.5 to 10.
• Drive ranges from 0 to 1 and boosts the signal before filtering.

Inputs And Outputs#

Port	Type	What It Does
In	Audio	Audio source entering the filter.
Cut	CV	Modulates cutoff frequency.
Res	CV	Modulates resonance.
Drive	CV	Modulates input drive amount.
Out	Audio	Filtered lowpass output.

Controls Reference#

Control	Range	Default	Behavior
Cutoff	20..20000 Hz	1000 Hz	Sets the lowpass cutoff frequency.
Res	0.5..10	1	Sets resonance intensity.
Drive	0..1	0	Raises the input gain before the filter core.

CV Behavior#

• Cut uses exponential modulation.
• Res is linear and clamped to the supported range.
• Drive is intended as a positive control input; the panel labels it 0V~+5V.
• Parameter changes are smoothed in the DSP for cleaner sweeps.

Character Notes#

• This is the more dramatic of the two MS-20 filters.
• Drive changes the way the core is hit, so it affects edge and texture, not only loudness.
• If you need a harder, more unstable-feeling lowpass than the ladder modules, this is the right place to start.

Panel Layout#

• The large center knob is Cutoff.
• The small left knob is labeled PEAK, which corresponds to Res.
• The small right knob is Drive.
• CV inputs for Cutoff, Peak, and Drive sit above the SIGNAL IN and SIGNAL OUT jacks.