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Korg Ms20



korg Ms20
audio demo trend price : 1200€
manual   schematic demo video comments

Korg Ms-20 (1978)

Monophonic Synthesizer MS a synthesizer family born just after the famous PS Polyphonic Synthesizer production.

Snubbed for years, today re-appreciated for its harsh unpredictable characters.

korg synthesizer

patch bay

info KEYBOARD (weight: 8 Kh.) compact and portable about featuring a 37keys (no velocity)
The synth is well-built with 38 precise knobs precise and reliable in time, main panel features 35 patch connections like a modular to interrupt the pre-routed signal, however it is not really modular: it' s just a synthesizer with some external routing signal even if some synthesis section are path-fixed hardwired.
On the left side a modulation wheel generating +/-5 voltage and a nearby button switch for trigger or re-triggering some synthesis functions on main patch panel.
All functions are organized with different drawn sections with some strange captions and may soon results in synthesis term confusion.

ac Power supply is internal.

edit VOICE subtractive monophonic synthesis.
Dual analog Oscillators VCO with variable octave heights and indipendet volume mix. Mastertune potentiometer affects both VCO pitch while and portamento speed adjusts the note legato play.
edit OSCILLATORS ├žet's deep the VCOs:
- VCO1 octave range from 32' to 4' has 4 Waveforms triangle, saw, white noise amd pulse with variable width.
- VCO2 has higher octave range from 16' to 2' but has less waveform options saw, square, ring modulator and a fixed 25% pulse (it lacks width) + a pitch detune +/-5 semitone range.


filter FILTER it' s multimode VCF with 2 serial filters: single voltage-controlled highpass featuring 2-pole slopes + one lowpass one with same slope. Both VCF have independent resonance emphasis potentiometer Peak that reach self-oscillation with a nice resulting sinusoidal and they can be combined to obtain the famous Screaming filter with BandPass or notch-reject. The filter CUTOFF can be also driven by patching CV section with CV IN VCF LP and CV IN VCF HP or Envelope 2 (EG2).
VCF is the most interesting aspect of the synthesizer and results perfect for electro music and various noise creations, even if sometimes you never know precisely what you will obtain turning the knobs. There are 2 filter hardware versions, depending on the production series: the first one is IC 35 filters and second one has a smaller board with custom integrated chips.
The MS filter has been cloned many times, in particular in a wonderful filter box called Frostwave Resonator with many CV controls.

fx EXTERNAL PROCESS another interesting VCF feature is that signal inputs can be filtered through the double filter in a dedicated section ESP External Signal Processor complete with an Envelope Follower function (same featured in the Ms-03) and a pitch-to voltage tracker generator.
original scan

adsr ENVELOPE two in total:
-EG1: 3 stages ADSR Attack-Delay-Release while
-EG2: 5 stages
ADSHR Attack-Decay-Sustain-Hold (keeps Sustain before Release segment)-Release.
ADSHR is also default EG for VCA (both OSC) amplitude, but you can also patch VCA initial gain with apposite CV patch and EG2 that define also Envelope for both VCF Cutoff.synthesis
lfo LFO a single modulator MG with progressive variable waveform from rectangular to triangular (LFO outputs 2 CV with separate LFO triangle and rectangular at same frequency) or use an external one with TOTAL IN CV. ->REMEMBER<- to activate MG T/EXT "NOT" EG/EXT.
SAMPLE and HOLD section for some random or stepped modulations and you have to patch it for yourself: usually plug white noise IN (or better, pink) and do not forget S/H clock frequency or it will not work (LFO Square clock CV out usually does the job).
LFO modulates at the same time: VCF LP CUTOFF- VCF HP CUTOFF -VCO1 VCO2 pitch with internal frequency.


MS-10: the little brother: Just one single VCO, but still sounds good and it has some extra gimmicks like the PWM CV IN not featured on Ms20.

MS-50: basically a Ms10 with totally open structure with a LOT of patching routing Input/output. Quite hard to find, maybe the rarest of the bunch after the blackboard.

SQ-10: dedicated MS sequencer, 12 steps, really on the fly pots.

VC-10: a vocoder with some CV interaction with MS family. Sounds like a big juicy frog!

ms20 family with ms10

korg ms20 blackboard educational version
SPECIAL MS-20 BLACKBOARD EDITION: a special huge Ms20 version for synthesis learning purposes, it is almost impossible find (it seems to be around 40 produced) but it has the same specs.
Only worth only if you are a rich collector because it is pretty awkward to use.

MINI Ms-20 : a remake from 2013, did not tried it yet. Buzz indicates it seems to be vastely different to original model. new korg mini ms20


korg ms20 and nice cat




KORG MS-20 ESP DEMO Sounds of the Korg MS-20 Korg MS-20 01
KORG MS-20 ESP DEMO Sounds of the Korg MS-20 Korg MS-20 01




korg ms-series


korg ms20 flyer


korg ms20 scan

korg ms20 brochure


korg ms20

original scan

original scan

Korg ms20 VST
FUN! Korg ms20 VST

Monkey Island Ms20
Monkey Island Ms20


weird mod!
weird mod!



behind side close up


- filter(s)!
- patching flexibility
-Signal processor


- expensive
- Osc not so fat
-panel not so obvious.


"Harsh machine, a cornucopia of electronic sounds and effects. It is essential to deepen patch bay capacity to open a brand new world. "

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all snapshots*, sounds, texts copyright Polynominal.com / Eric Pochesci
*mini- ms20 pictures from Korg website, custom ms20 from craiglist, ms20 merchandising from ebay, monkey island is a LucasFilm Games
frostwave resonator picture from ebay auction

korg ms20 4.5 out of 5 based on 17 ratings. price €1200