Korg MS-20 Mini Music Synthesizer

&

SQ-1 Sequencer

© Brooke Clarke 2016

Background
Description MS-20 Mini
    Versions
    Software Versions
    Research
Keyboard & Control Voltages
SQ-1 Description
    LittleBits
Accessories
Photos
Related
References
Links

Background 

A few decades ago I had a Yamaha DX7IID with an add on printed circuit board that allowed it to play "The Entertainer" (YouTube), see my Music web page..  It was possible to assign different instrument voices to the various parts.  Quite amazing.

Recently I learned about the Linnstrument (Music#Linnstrument) and was very impressed.  And started looking into low cost analog music synthesizers.  Note that using just your finger it's possible to modify 3 parameters, pitch, amplitude and a third parameter such as pulse width and achieve a high degree of expressiveness without a really fancy synthesizer.  But ideals you would use one of the few synths listed on the Linn Instruments web page that are polyphonic and that can process the very large amount of MIDI data that it puts out.

So in the process of looking for a synth to go with a Linnstrument (which I don't have and probably will not get) I found the Korg MS-20 Mini.  Which is a remake of the classic MS-20 (Wiki).  It's called "Mini" because the size is smaller and that's achieved by using 3.5mm (1/8") jacks instead of the 1/4" phone jacks used in the original MS-20 as well as shrinking the size of the keyboard for an overall 86% of original size.  There are some additions like MIDI In and USB In & Out &Etc.

Description ms-20

Although the DX7 may be the highest production volume music synthesizer ever made (about a quarter million units) the MS-20 is not far behind and catching up. 
It outputs line level sound, but there is no built-in speaker, so needs an external amp and speaker or can be fed into a mixer or analog recorder.
Has MIDI in and out as well as a USB-B jack.

Versions

Version
Release
Date
Comments
original 1978 keys make mechanical click
tuning varies w/temp
115 VAC power
No MIDI
No USB
MS-20ic
Instrument
Controller
2004 no sounds out only MIDI
use to drive iPad
3.5mm jacks
Mini
2013
Stable tuning
DC power
MIDI & USB
3.5mm jacks
MS-20 Kit
2014
Very similar to the original
switchable "35" or new filter
VCO sync switch
Hz Volt options
MS-20M
Module
2015
Like the MS-20 Kit
no keyboard
comes with the SQ-1 sequencer

Software Versions

1995 - Trinity (Wiki) digital hardware workstation
1999 -  Oasys PCI (Wiki) PCI card & Triton (Wiki) digital hardware workstation
2004 - Known as the "Legacy Collection".  Consists of the MS-20, Polysix (Wiki: 1981 hardware,Wavestation, Legacy Cell & MS-20ic
2005 to 2009 - Oasys (Wiki: hardware Workstation Computer)
2007 - Legacy "Collection Analogue Edition".  Consists of the MonoPoly, M1
2011 - Kronos (Wiki) hardware workstation for x86 PC type computers except running Linux op system. Can load & play Yamaha DX7 files
2012 - Kronos X hardware workstation for iOS version 2 & Kronos 2 for iOS version 3.
2013 - iPolysix (Korg), Polyseq, Durms-6, Mixer-8, Polysix+KAOSS PAD, Polyshare
???? - KORG Gadget, KORG Module, iMS-20 (Korg), iKaossilator, iM1, iDS-10, BLuetooth MIDI Connect

Research

 While waiting for the MS-20 and SQ-1 to get here I've been doing some on line research.  Here are some links.

YouTube

Korg MS-20 Mini and Make Noise Modular Pt. 1 - MS-20: Log pitch scale, Eurorack: exponential pitch scale - Harvestman English Tear (AnalogueHaven) does the conversions.
Korg MS-20 Mini and Make Noise Modular Pt. 2 -
Korg MS-20 Mini and Make Noise Modular Pt. 3  -
Harvestman – English Tear / NAMM Notes
MS20: FM & the Momentary Switch by willsanquil -
Inauguration of The MS-20 (mini) Synth Synesthesia  by Sounds & Things -
Korg MS 20 mini noise problem -
Korg MS-20 mini - Noise Problem?  by KORGINC -
KORG iMS-20 v1.1 Demonstration Movie (MS-20ic)  - with iPad - "You need to use a powered USB hub. I use a battery powered CyberPower USB 2.0 Mobile Battery Powered Hub CP-H420MP."

MIDI

MIDI-Ox - MIDI software for PC

Web Pages

MS-20 Patch library - most do not have audio clips, but there's a lot of them.
Muff Wiggler - Korg MS-20 Re-issue, MS20 mini mods, Korg MS20ic Controller,
Mutable Instruments - Eurorack module tester - plans
electrical audio: Korg MS-20 mods (full size and mini)
Vintage Synth Expolorer - Korg MS-20 Mini -

Keyboard & Control Voltages

First a table showing the 88 keys available on a regular piano keyboard, their frequency and the Control Voltage from the MS-20 keyboard. (Wiki)

Note
Octave 0
Octave 1
Pedal C
Octave 2
Deep C
Octave 3
C3
Octave 4
Middle C
Octave 5
Tenor C
Octave 6
Soprano C
Octave 7
Double Hi C
Octave 8
Hz
Theory
V
Hz
meas
Hz
V
Hz
meas
Hz
V
Hz
meas
Hz
V
Hz
meas
Hz
V
Hz
meas
Hz
V
Hz
V
Hz
V
Hz
V
B
30.8677


61.7354


123.471


246.942


493.883


987.767

1975.53

3951.07



A#
29.1352


58.2705


116.541


233.082


466.164


932.328

1864.66

3729.31



A
27.5000


55.0000


110.000


220.000


440.000


880.000
1760.00

3520.00



G#



51.9131


103.826


207.652


415.305


830.609

1661.22

3322.44



G



48.9994


97.9989


195.998


391.995


783.991

1567.98

3135.96



F#



46.2493


92.4986


184.997


369.994


739.989

1479.98

2959.96



F



43.6535


87.3071


174.614


349.228


698.456

1396.91

2793.83



E



41.2034


82.4069


164.814


329.628


659.255

1318.51

2637.02



D#



38.8909


77.7817


155.563


311.127


622.254

1244.51

2489.02



D



36.7081


73.4162


146.832


293.665


587.330

1174.66

2349.32



C#



34.6478


69.2957


138.591


277.183


554.365

1108.73

2217.46



C



32.7032
1.000

65.4064
1.999

130.813
3.998

261.626
8.00

523.251

1046.50

2093.00

4186.01

My YouTube Videos:

Korg MS-20 Mini Control Voltages & Frequencies - First showing the DC Voltage from the keyboard, then the corresponding frequencies.
I made a mistake in the video 45 seconds where the frequency of the very left most key (1.000 Volts) it's C1, not A0, so should be 32.7 Hz, not the 27.5 Hz for A0 which is not on this keyboard, i.e. the keyboard starts with C1.  Turning the VCO2 pitch up slightly will bring the frequency to 32.7.  So Korg allows the very left key (C1 in terms of keyboard layout) to be mistuned down to A0 just like a grand piano.

The frequencies with the VCO2 pitch fully CCW look very similar to A0, A1, A2 & A3 and when the VCO2 Scale switch is moved up range the frequency is modified by 2X, 4X or 8X giving a maximum frequency of 1852 which is sort of like A6.  There's no provision to get to C7.

SQ-1 Sequencer Description

There are two banks of 8 levels each when active sends out a DC voltage between 0 and 1, 2, 5 Volts/Octave or 8 Hz/Volt according to which of the  CV-A Range (4 buttons) or CV-B Range  (4 buttons) has been selected while holding down the Function button.  This box has no sound generating capability, it only outputs Control Voltages (CV) or MIDI or USB data.

The On/Off button is just to the right of the Mode rotary switch in the upper left corner.  Hold down for a few seconds to turn unit off.

This unit runs on a couple of internal AA batteries.

Korg web page with connection info for MS-20M, MS-20 Mini, LittleBits.

Wiki page on Control Voltage and Gate signals.

cdm  -Here’s What Korg’s $99 SQ-1 Step Sequencer Can Do [In Depth Guide] -
YouTube

Korg SQ-1 - How to play ratcheting sequences -
Korg SQ-1 - How to transpose Midi-notes and send velocity -
Korg SQ-1 knobs - pimp - uses 6 mm black control knobs 32106
On the run - SQ-1 + MS-20, patch & live knob turning
Korg SQ-1 Sequencer MS-20 MicroKorg Jam -

LittleBits

While I was looking at what low cost music synthesizers were available I came across the Korg LittleBits synth.  In fact one of the comments was that for someone interested in a music synth the MS-20 would be a better choice (music capability for the money), so I got the MS-20 Mini.  But . . .  LittleBits is a child friendly way to work with electronics since it uses a 5 Volt power supply and magnets to connect modules (no soldering required).  Open source (GitHub, Files ) hardware and software.

The magnetic connectors (male & female) have 3 terminals (ground, signal & +5 volts).  While there are Korg music modules there are also many other modules all offered under open hardware and software license.

Heavy use is made of ATmega micro controllers (same as used in Arduino (Wiki) boards). 

The LitttleBits output is a combined Gate plus Control Voltage output so only a single mono cable is needed.  When connecting the SQ-1 to the MS-20 Mini 2 cables are needed (CV and Gate).

Accessories

The MS-20 comes with some 3.5mm patch cables.  But either a 3.5mm "Y" or stackable 3.5mm mono cables from Tip Top (AudioHaven).

Custom cable RG-174 coax BNCm to 3.5mm mono - for use with scope and HP 4395A spectrum analyzer.
Custom cable 3.5mm mono - 1/4" phone plug for connecting Yamaha HS5 active (amplified) speaker.
Yamaha HS5 - small easy to carry (not as good as the NS10M, but far lower price).
MIDI cable
USB - MIDI adapter and WIN7 software

Photos

MS-20 Mini

Fig 1 Used unit came in factory box and packing.
Korg MS-20
                      Mini Music Synthesizer
Fig 2
Korg MS-20
                      Mini Music Synthesizer

Fig 3 SQ-1 Sequencer & KA350 power supply in boxes.
Korg MS-20
                      Mini Music Synthesizer

Fig 4  Front
Korg MS-20
                      Mini Music Synthesizer
Fig 5 Back
Korg MS-20
                      Mini Music Synthesizer
Fig 6 KA350 World AC adapter, 9V <= 1.7 Amp output.
Positive center contact.  9.15 V no load.
Power Plug: 5.5 mm OD (not the more standard 5.2 mm)

Korg MS-20
                      Mini Music Synthesizer





SQ-1

Fig 1 SQ-1 Sequencer
Korg SQ-1
                      Sequencer
Fig 2  USB output and battery compartment
Korg SQ-1
                      Sequencer
Fig 3 Front panel.  Note Midi out 1/8" stereo jack.

Korg SQ-1
                      Sequencer





Related

HP 4395A Spectrum Analyzer
Music

References


Links

PRC68, Alphanumeric Index of Web pages, Contact, Products for Sale
Page Created 6 Nov 2016