KORG MS SERIES

The Korg MS series was released by Keio Electronic Lab in 1978. Whilst one instrument within the range has taken on a life of its own, there are some interesting siblings left in its wake that we'll look at below.

 

If you want the full history of Korg, I recommend my feature length documentary "Traveler: A Korg Retrospective" below.

Fumio Meida demonstrates the VC-10 at the launch of the MS Series in 1978. Chairman Tsutomu Katoh stands at the end of the row of spectators, photo provided by Korg. MS range photograph taken by Hideki Ishikawa at the Nakatsugawa Korg Museum, Japan.

FAMILY MEMBERS

MS-01: Foot Controller

 

A control voltage / attenuator pedal that can be connected to the synths within this range to control any of the compatible functions. This can be volume or filter cutoff, but it could also be pulse width or LFO frequency or any number of things.

The pedal runs from a standard 9v battery.

MS-02: Interface

 

This box broadly converts two things: Firstly, Korg's exponential "hertz per volt" (Hz/V) standard into the linear "volts per octave" (Octave/V) standard developed by Bob Moog and used by ARP, Sequential, Roland, Oberheim and many others. Secondly, the module inverts Korg's "short trigger" (S-Trig) standard to the "voltage trigger" (V-Trig) standard used by most other manufacturers. 

 

This means that the module can be used to interface a Roland sequencer with a Korg synth or a Korg sequencer with a Moog synth etc.

 

There's also knobs to set the frequency and width (tracking), a series of buffered multiples (junctions) and a two-channel adding amplifier with inputs for negative and positive sources.

MS-03: Signal Processor

Very similar to the External Signal Processor section of the MS-20 described below, this module takes a monophonic audio signal and converts it to a control voltage, (either Hz/V or Octave/V) and also generates triggers and an envelope from the audio signal. The latter is commonly known as an "envelope follower".

 

Essentially, this allows the user to then control the frequency of a synthesizers oscillators, trigger its envelope generators and contour a parameter (e.g. filter cutoff) from an instrument or microphone.

 

Portamento can be introduced into the voltage changes and the direct signal also runs out of the unit too, so it could just be used as a preamplifier or a way to drive and overload a signal.

MS-04: Modulation Pedal

On the left, this pedal contains an LFO that outputs either triangle, square or random (sample & hold) waveforms. It can also be switched to a glissando option. The two knobs in this section set the speed (frequency) of the LFO or glissando and the level.

 

On the right hand side is a bender, which is just a voltage that is controlled by moving the pedal; the width knob sets the range.

 

On the reverse side of the pedal are two outputs that can be set to LFO, LFO and Bend or Bend. The switch at the far end activates or disengages the channels.

 

The example of this pedal I experienced was completely untouched and still had the protective plastic on it from the factory!

MS-10: Monophonic Synthesizer

The baby of the three synthesizers in this range, the MS-10 essentially has one of each of the main building blocks of a basic synthesizer; a VCO, a VCF, a VCA, an EG and an MG (LFO).

 

VCO: 

Range: 32' - 4'

Waves: Triangle, Sawtooth, Pulse, Noise

Control: Pitch and PW/PWM

Modulation: From MG, EG or External

 

VCF:

Design: Korg-35

Type: 2-pole Lowpass

Control: Cutoff frequency, Peak (resonance)

Modulation: From MG, EG or External

 

VCA:

Normalled to EG, but an external control signal can be added to the EG or used in place of it (if the EG is not being triggered).

 

The EG cannot be disconnected from the VCA and this was due to Korg's decision to avoid situations where the instrument won't make any sound, which might put off or confuse the user.

 

EG:

Stages: Hold, Attack, Decay, Sustain, Release

Output: Bi-polar (sustain is 0v)

 

MG (LFO):

Waves: Continously variable sawtooth/ triangle/reverse sawtooth and pulse waves (latter accessible via the patch panel)

Control: Wave shape and Frequency

 

Other:

Portamento Time

External Signal Level

Volume

 

Patch Panel:

VCO frequency and PWM control inputs

External signal input

VCF frequency control input

VCA initial gain control input

MG wave outputs

EG reverse (inverted) output

Noise generator outputs

Mod wheel voltage output

VCO CV input (Hz/V)

Keyboard CV output (Hz/V)

EG trigger input (S-Trig)

Keyboard trigger output (S-Trig)

Signal output

MS-20: Monophonic Synthesizer

The most famous, most reissued and most copied member of this family (see MS-20 versions below). This synth doubles most of the features of the MS-10; There's two VCOs, two VCFs, two VCAs, two EGs and one MG.

 

VCO 1:

Range: 32' - 4'

Waves: Triangle, Sawtooth, Pulse, Noise

Control: Pulse Width

 

VCO 2:

Range: 16' - 2'

Waves: Sawtooth, Square, Pulse, Ring Mod

Control: Pitch

 

VCO Frequency Modulation: From MG or Total External, EG1 or External

 

VCFs:

Design: Korg-35

Type: 1-pole Highpass and 2-pole Lowpass in series.

Control: Cutoff frequency and Peak (resonance) for each.

Modulation: From MG or Total External, EG2 or External for each.

 

VCA 1:

Normalled to EG 2, but an External control signal can be added to the EG or used in place of it (if the EG is not being triggered).

 

VCA 2 in patch panel (mentioned below)

 

EG 1:

Stages: Delay, Attack, Release

Output: Unipolar 

 

EG 2:

Stages: Hold, Attack, Decay, Sustain, Release

Output: Bipolar (sustain is 0v)

 

MG (LFO):

Waves: Continously variable sawtooth/ triangle/reverse sawtooth and pulse waves (latter accessible via the patch panel)

Control: Wave shape and Frequency

 

Other:

Portamento Time

Master Tune

Volume

Patch Panel:

Total External control input

VCO frequency control input

External signal input

Highpass VCF frequency control input

Lowpass VCF frequency control input

VCA initial gain control input

MG wave outputs

EG 2 normal and reverse (inverted) outputs

EG 1 reverse (inverted) output

Sample & Hold input, clock and output

VCA 2 signal input, output and control input

Noise generator outputs

Mod wheel voltage output

Intermittent Switch output (S-Trig)

VCO 1+2 CV input (Hz/V)

VCO 2 CV input (Hz/V)

Keyboard CV output (Hz/V)

EG 1+2 trigger input (S-Trig)

EG 2 trigger input (S-Trig)

Keyboard trigger output (S-Trig)

Signal output

Headphone output

 

External Signal Processor:

Signal input with level and output

Non-resonant low cut (highpass) and high cut (low pass) filters form a bandpass filter and the signal can be taken out post-BPF.

Frequency to voltage convertor (monophonic) with CV adjust and output.

Envelope follower and trigger generator with threshold and outputs.

MS-20 versions:

 

Mark I 1978

The original version with Korg-35 filters

 

Mark II Circa 1980

Revised filter design using OTAs on a daughter board which is attached by a screw on the front panel. This usually identifies which revision the synth is without needing to open it, but there are exceptions!

 

Blackboard Circa 1978

A giant blackboard version of the synth used to teach synthesis at Keio’s synthesizer school opened in 1978 (see photo). This is a fully functioning MS-20 and not just a prop!

Photo and scans by Hideki Ishikawa at the Nakatsugawa Korg Museum, Japan.

 

MS-20 Legacy Collection (2004)

MS-20 ic (2004)

DS-10 for Nintendo DS (2008)

iMS-20 for iPad (2010)

MS-20 Mini (2013)

MS-20 Kit (2014)

MS-20M Desktop (2015) 

MS-20 FS (2020)

 

Some copies, emulations and modules:

AE Modular MS-20 Filter

Arturia MS-20V

Behringer K-2

Bristol MS-20

Cherry Audio PS-20

Doepfer A-106-1

EAS Miss 10 VCF/VCA

Kaussotronics KS-20 Filter

SoundForce Dual Filter

Synthesis Technology MOTM-420 

MS-50: Expander Module

The rarest of the three synthesizers in the series, the MS-50 is also the most advanced with its keyboardless, fully modular design. Depending upon the unit, it can be labelled as either "Synthesizer" or "Expander Module". The latter seems to relate to US voltage units, but there are exceptions.

 

VCO:

Range: 32' - 4'

Waves: Simultaneous Triangle, Sawtooth, Pulse

Control: Pitch, PW/PWM, x2 frequency modulation amounts

Jacks: x2 CV inputs (Hz/V and OCT/V), x2 frequency modulation inputs, PWM input

 

VCF:

Design: Diode Ring (CA3019)

Type: 2-pole Lowpass

Control: Cutoff frequency, Peak (resonance) and modulation amount.

Jacks: Signal in and out, cutoff frequency control input.

 

VCA 1:

Control: Modulation intensity and Low cut filter

Jacks: Signal in and out, amplitude control input.

 

VCA 2:

Jacks: Signal in and out, amplitude control input.

 

 

EG 1:

Stages: Attack, Decay, Sustain, Release

Jacks: Unipolar output, bipolar output, bi-polar inverted output, trigger input

 

EG 2:

Stages: Hold, Delay, Attack, Release

Jacks: Unipolar output, bipolar output, trigger input and delay trigger output

 

MG (LFO):

Waves: Triangle, Sawtooth, Inverted Sawtooth, Pulse

Control: Frequency and PWM

Jacks: Frequency modulation input, PWM input, wave outputs (x4)

 

Adding Amplifier:

3 channel with level controls

Ring Modulator:

A and B inputs and RM out

 

Sample & Hold:

Input, output, external clock input, internal clock output (with frequency control)

 

Noise generator:

White and Pink

 

External Signal Processor:

Signal input with level and output.

Envelope follower and trigger generator outputs.

 

Utility:

Voltage Supply, Inverter, Volt Meter, Divider, Trigger Switch, Headphone Amp, buffered multiples (junctions)

VC-10: Vocoder

VC-10: Vocoder. Probably the coolest looking member of the series, the VC-10 sports a gooseneck microphone with custom Korg engraving. Whilst it looks great and is convenient, it's not the greatest mic in town. Thankfully, there's an input jack to defeat the connection to this mic and replace it with another. The same input can be hacked and used for replacing the modulator with an external audio sign.

 

The modulator defaults to the internal tone generators of the VC-10 which are controlled by the keyboard, but this can be replaced by an external signal.

 

There's external CV control of the internal tone generators as well as "accent bend" (a kind of envelope mod of pitch meant to emulate the sliding nature of the human voice), an LFO for vibrato and an ensemble circuit. There's also level and balance controls, one of which blends in white noise.

SQ-10: Sequencer

An analogue sequencer designed to pair with the MS synths or, via the MS-02, synths from other manufacturers.

 

The SQ-10 has three 12-stage channels, two of which can be chained together to form a sequence of up to 24 steps. There are six switchable playback modes as well as duty cycle control to introduce swing. Channels A and B have portamento controls.

The third channel (C) can be used for a parallel sequence of 12 steps or for modulation.

The SQ-10 can be started and stopped from a footswitch or S-Trig signal, it can run from its own clock (the frequency of which can be modulated), or it can be stepped through from an external trigger.

 

There is a reset trigger input and each stage has a trigger out, which is how sequences of different lengths are achieved.

 

Finally, there is asumming mixer which is used to combine the CVs of channels A and B when using them in series.

The SQ-10 is the only other member of the original family to have some sort of official reissue, in the form of the SQ-1 (2015).

Honourable Mentions:

Korg made two tape echoes in the late 70s and the SE-500 is  worth a mention because it has external control inputs allowing for effect toggle, feedback reset and tape speed to be controlled from any of the MS synthesizers and/or the SQ-10 sequencer. Here's a video I made demonstrating this in action.

FK-3 and FK-5 pedals. Not officially part of the MS series, but worth a mention because they are closely related to the MS-01 and MS-04 and can interface perfectly with any of the synths from the range.

FK-3: A simple volume pedal with two inputs and two outputs. The pedal controls the volume.

FK-5: Foot Balancer. As with the FK-3, there are two inputs and two outputs, but the pedal cross fades between them, rather than controlling the volume of both. The example I saw of this pedal was in its original box and original wrapping and was basically untouched for over four decades!

There is also an FK-1 VCF / "Synthe Pedal", FK-2 "Mr Multi" Phase-Wah pedal and an FK-4 "Polyphonic Ensemble" for use with the PE-2000, but these aren't relevant to the MS range.