Korg MS-20

The Korg MS-20 is one of the most iconic analog synthesizers ever made. Originally released in 1978 and produced until 1983, this semi-modular monophonic synth has shaped countless records across electronic, industrial, and experimental music. Its aggressive filters, extensive patch bay, and hands-on design deliver a raw, characterful sound that modern digital synths still struggle to replicate. Today it remains widely available as the MS-20 Mini (86% scale, mini-keys) and the MS-20 FS (full-size reissue with selectable filter revisions).

Sound Architecture

The MS-20 features two voltage-controlled oscillators. VCO1 offers triangle, sawtooth, variable-width pulse, and white noise. VCO2 provides sawtooth, square, pulse, and ring modulation. The real star is the dual filter section: a high-pass and low-pass filter in series, both 12dB/octave with resonance that can be pushed into self-oscillation for screaming, biting tones. Early production units used Korg-35 filter chips with a more aggressive, sought-after character, while later units switched to LM13600 OTA-based filters with a slightly different tone. The MS-20 Mini uses the earlier Korg-35 circuit; the MS-20 FS lets you switch between both.

Patch Bay and Modulation

The front-panel patch bay with approximately 34 jacks is what elevates the MS-20 beyond a standard monosynth. You can reroute the signal flow, feed external audio through the filters using the built-in ESP (External Signal Processor) with its envelope follower and frequency-to-voltage converter, or create feedback loops for wild, unpredictable textures. The modulation section includes an LFO, two envelope generators—EG1 (a simpler DAR: Delay/Attack/Release) and EG2 (an extended HADSR: Hold/Attack/Decay/Sustain/Release)—plus sample & hold and a modulation VCA.

Note that the MS-20 uses Hz/V scaling and S-Trigger rather than the more common V/Oct and V-Trigger standards, which matters when connecting to other analog gear.

Build and Playability

The original MS-20 has 37 full-size keys in a compact desktop form at 7.7 kg. The MS-20 Mini shrinks this to 86% scale with mini-keys at 4.8 kg. Every parameter has a dedicated knob on the front panel, making sound design immediate and intuitive. The MS-20 is really about tweaking knobs and patching cables rather than traditional keyboard playing.

Who Is This For?

• Sound designers looking for raw, aggressive analog tones and experimental textures
• Electronic producers who want hands-on control without menu diving
• Synth beginners interested in learning semi-modular synthesis with a rewarding instrument
• Studio musicians who need a characterful monosynth for bass, leads, and effects

The MS-20 remains one of the best entry points into analog semi-modular synthesis. Whether you grab a vintage original, the compact MS-20 Mini, or the full-size MS-20 FS, you are getting a proven instrument with decades of creative history behind it.