Korg MS 20 - Notes 1

The MS 20 comes pre wired but the connections can be broken and re-routed using patch cables.

I'll break it up into the following sections
1. Modulation Generator
2. Envelope Generator 1 (Pitch Envelope)
3. Envelope Generator2  (Filter  & main VCA Envelope)
4. Keyboard
5. Mod Wheel & Momentary Push Button
6. Sample & Hold.
7. ESP (External Signal Processor).


1. Modulation Generator
This Korg speak for the LFO

It's  hardwired to three parameters:
a. The pitch of VCO1 & VCO2
b. cutoff of the highpass filter
c. Cutoff of the lowpass filter.

 Here is a close up of the internal routing:

Only the Triangle / Saw waveforms are hardwired . If you wish to use the LFO's square waves, you will need to patch it.

Adjusting the control panel knobs between MG & T.EXT will effect the mix of wave forms

A bit about the T. EXT.
This refers to the Total External input.

Any CV plugged into here will effect the pitch of VCOs 1 & 2, plus the Cutoff of both filters simultaneously.

2. Envelope Generator 1
The patch panel doesn't show clearly where its hardwired too.
You can see that it has 2 outputs: a normal & reverse wave form.

 It's actually connected to the pitch of the two VCOs. (via the frequency input on the patch panel)

 You can apply this envelope to the VCOs by using the EG1 amount control.

If you plug something into the frequency input, you will break the connection between EG1 & the VCOs.

3. Envelope Generator 2
This is wired to the filters and the main VCA.
It controls the filters' cutoff.

The hardwired connection to the VCA cannot be cut, but you can add extra CVs to modify the signals from EG2 via the initial gain jack. EG2 also has a reverse output.

EG2 is applied to the Filters using thetwo EG2 amount controls.
One is for the HP filter, and the other for the LP.
The External inputs give you flexible control over how you modulate each filter.
Above each EG2 control is a MG control. Thus the MG is still connected and can be used in conjunction with the External input sources.

You can plug in all manner of CV like the mod wheel, noise, EG1, the square MG, a sequencer, etc etc.

4. The Keyboard
It's default is to of course send CV to control the pitch of the VCOs.

In addition it sends gate signals to both EGs

You can break the connection to both EGs by plugging something into TRG IN.
Use this is you are using an external sequencer such as an SQ 10 to trigger notes. If you wish to just trigger EG1, use EG1 TRIG IN.

Being able to access the CV of the Keyboard is useful. Use it to control the filter for example.
You may also want to break the keyboard connection to one of the VCOs, by plugging in for example a LFO, the mod wheel or a sequencer.