The semi-modular monosynth that, alongside generating its own sounds, was designed to process other people's.
Korg released the MS-20 in 1978 under the design lead of Fumio Mieda, alongside its single-oscillator sibling the MS-10, the keyboardless MS-50 module, the SQ-10 sequencer and a small auxiliary catalogue of foot controllers, modulation pedals and the VC-10 vocoder. The design brief was deliberate: build a semi-modular monophonic synthesiser at a price point that would put patching flexibility within reach of musicians who could not afford an ARP 2600 (US $2,650) or a Minimoog (US $1,595) or even a Sequential Pro-One (US $945). The MS-20 shipped at US $750, about 28% of the ARP 2600's price for somewhere between a third and a half of its working capability and the contemporary synthesiser press accordingly called it the "poor man's ARP 2600" across the entirety of its production run.
The structure is straightforward to catalogue. Two voltage-controlled oscillators with four waveforms each (sawtooth, square, triangle, white-noise on VCO 1; pulse-width-modulated alternatives plus ring modulation), feeding into a two-stage filter chain: a self-oscillating high-pass filter followed by a self-oscillating low-pass filter, each with its own cutoff and PEAK (resonance) control. Two voltage-controlled amplifiers, two envelope generators (one with hold-and-delay shaping, one standard ADSR), one low-frequency oscillator with two waveforms and a 37-key keyboard with assignable mod wheel. The technical distinction relative to the contemporary monosynth market is the dual-filter chain: most competing instruments had a single filter and the MS-20's combination of high-pass and low-pass with self-oscillating resonance on both stages gave the unit its screaming aggressive character, the property the synthesiser press later called "the MS-20 sound". The Korg-specific oscillator and filter chips that the unit ran on (proprietary parts, not the contemporary Curtis or SSM standards) are the technical reason the sound did not transfer cleanly to later analogue clones and the reason original units retained value across the four-decade later collectability cycle.
The second distinction is the External Signal Processor, occupying about a quarter of the right-hand side of the front panel. The ESP is a complete audio-input processing chain: preamp, high-pass and low-pass filters, an envelope follower and a frequency-to-voltage converter. Source audio entering the ESP's input jack can be passed through the filters as a standalone processor, can have its amplitude envelope extracted to drive the synth's own VCAs or can have its pitch converted to a control voltage that drives the VCOs. The implication: the MS-20 is the only contemporary semi-modular synthesiser in its price range designed from the start as an audio-input processor, not just a tone generator. The operator could plug a guitar, a microphone, a drum machine or another synthesiser into the ESP and either play the MS-20's filters with the external source or have the external source play the MS-20's oscillators. This is the capability the file is mainly documenting.
The patch bay on the right-hand side of the panel uses about thirty 1/4-inch jacks arranged in a dense grid: signal outputs and inputs at each stage of the synthesis chain, modulation sources (envelopes, LFO, sample-and-hold) freely routable to modulation destinations (filter cutoffs, oscillator frequencies, amplifier levels, ring modulator), trigger and gate inputs accessible. The semi-modular distinction is that the synth functions without any patch cables through the hard-wired default routings (VCO → mixer → HPF → LPF → VCA → output); the patch bay only becomes operative when the operator inserts cables, at which point the patched signal path overrides the default. This semi-modular design was a deliberate response to the ARP 2600's all-modular layout: the MS-20 could be played immediately as a conventional monosynth and could be patched as a small modular system when the method required it.
The user of the MS-20 within the genre this archive covers is DAF (Deutsch Amerikanische Freundschaft), whose 1980–1982 catalogue (Die Kleinen Und Die Bösen 1980, Alles Ist Gut 1981, Gold Und Liebe 1981, Für Immer 1982) was built mainly on Robert Görl's MS-20 plus Gabriel Delgado's vocal performances, with minimal additional instrumentation. The DAF method is the founding industrial-and-adjacent MS-20 case: the unit's distinctive screaming filter, fast envelopes and audio-input processing capability were the sound-source of the founding EBM-pivot records. Daniel Miller's 1978 single Warm Leatherette (released as The Normal, the founding release of Mute Records) was built on a Korg synthesiser of about this generation (the documented instrument is the MS-10, the smaller sibling, but the MS-20 was part of the same family and the Mute roster used both interchangeably across the early-1980s period). The early Mute catalogue (Fad Gadget, Silicon Teens, the early Depeche Mode period before they moved to a good deal more expensive equipment) ran the MS-20 across multiple releases.
Within the first-wave catalogue, MS-20 documentation is less clean than for the SH-101 or the TR-808. Throbbing Gristle's canonical equipment list centres on the custom Gristleizer, the ARP Odyssey, the Korg WT-10A tuner, the Roland Space Echo and the Beck Road tape setup filed at E·04; specific MS-20 use across the TG catalogue is not well-documented in the available record and the Bureau cannot confirm the claim sometimes made that the band kept two units. Cabaret Voltaire used Korg synthesisers extensively across the Western Works period (Stephen Mallinder and Richard H. Kirk both played them) and the MS-20 appears in some session photography, but the band's synthesisers are the EMS VCS-3 and the ARP 2600. Aphex Twin's catalogue (filed adjacent to the genre this archive covers) used MS-20s extensively, with Richard D. James known to have owned multiple units; Autechre's early period at Skam and Warp used them considerably; the 1990s analogue revival ran through the unit. Front 242 documented the MS-20 in their earlier catalogue alongside the Korg synth-bass equipment list.
The 1983 discontinuation happened alongside Korg's turn toward polyphonic digital synthesis (the Korg Polysix 1981, the Korg DW-8000 1985, the Korg M1 1988 which became the best-selling synth in history) and the industry-wide displacement of monophonic semi-modular analogue equipment by polyphonic digital instruments. The MS-20 remained available on the second-hand market across the entire 1983–2013 period at gradually-rising prices (the unit retailed at about US $300 in the late-1980s pawn-shop economy, rising to about US $1,500-$2,500 across the 2000s analogue-revival continuation). Korg reintroduced the MS-20 as the MS-20 Mini in 2013, an 86%-scale reissue with identical circuitry overseen by surviving members of the original engineering team, followed by the MS-20 FS in 2014 (a full-scale reissue at the original 1978 dimensions). Original units retail second-hand at about US $2,500-$4,500 in 2026, with mint-condition specimens fetching higher; the MS-20 Mini and FS remain in current production and provide the same essential method at a lower price point.
The Bureau holds the MS-20's significance to the genre this archive covers as methodologically specific: the unit's distinctive contribution to the first-wave's method was not its synthesis capability (the SH-101 filed at E·01 handles that better in most respects) but its audio-input processing capability via the ESP and the patch bay. The MS-20 was the synthesiser an industrial musician of the 1978–1988 period used when they wanted to push external sources (drum machines, voices, tape loops, other instruments) through aggressive analogue processing and that method is the unit's release within the equipment vocabulary the file is documenting.
Filed by Bureau editor · VAGO · c. the Norman period · last revised c. the High Middle Ages