Well don't I feel silly...

[Jay Vaughan]

> i must admit, the only way i know is to take it apart and identify the
> green chips on the PCB


>From wikipedia:

"Originally, the filters used Korg's proprietary KORG-35] thick film i.c. Later, the filters were redesigned to use off-the-shelf LM13600 OTAs. MS-20 units fitted with LM13600 filters have a small daughter board; the front panel on such units often has a tell-tale mounting screw whose head is visible in the vicinity of the VCA block diagram. However, a report to the Analogue Heaven email list in January 2010 identified an MS-20 with the front panel screw but containing the Korg 35 filter thick film circuit rather than the expected LM13600 circuit."


So it seems we have to take it apart to find out.  (Mine has the screw.)

I don't wanna take mine apart, either.