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Korg MS-20 Potentiometer Substitutes

Posted: Sun Jan 27, 2019 3:23 pm
by jakejoseph
I am working on an original Korg MS-20 - I have narrowed down its problems to the EG sections, and in addition, some physically broken pots in the other sections. The pots in question are labeled VR30-34 VR21,22 and 27.

I can get a reasonable approximation for the pots except for VRs 33,34, and 27. I cannot find a small format 2M audio pot anywhere.

Some questions - and I theoretically could calculate out the effects, or run a spice simulation, but I was hoping that someone knows the answers offhand. If not, SPICE it is.

1) What's the effect of swapping those 2Ms for the commonly available 1M? I know it will restrict the range - but will it still be usable?

2) Will replacing with a linear pot substantially change the UX?

3) Does anyone have a good source for those vertical mount potentiometers?

I'm going to try to use the adding a resistor to the wiper trick to change the 2M linear response as a first resort, but I prefer using original parts.

I'd appreciate anyone's thoughts on this.