[sdiy] KorgMS20 mods? help?

[Andre Majorel]

On 2007-07-27 10:25 -0400, peter edwards wrote:

> I've owned an MS20 for about 7 years now [...] Now that I've
> really gotten to know  every bit of this machine, I'd like to
> take it further and expand  it's functionality. [...] I'm
> interested in adding some controls like a pulse width CV input

Adding PWM is simple, did it on mine with just a jack and a pot.

> as  well as further patching options like ring mod inputs and an
> EXT in  mixer.

The ring modulator inputs won't work as well as you might hope as
it's not a real ring modulator, just a XOR gate. It's meant for
pulses only.

> I would also love to add some modules like one or two more  LFOs
> and CV mixers. Has anyone looked into modularizing?? VCO
> outputs, VCF ins and outs.

I have mid term plans to modularise mine. Much of the potential of
the MS-20 is locked because of the fixed signal path. Linear FM,
exponential FM, filter FM, notch filter, different signals paths
for each VCO are all possible by adding sockets and perhaps some
level-matching circuitry.

> Anyone out there with some experience who could give me some advice,  
> schematics, links, etc...

The schematics are on http://kornucopia.net/.

> I'm not a pro, but I've got some experience and I'm real good at  
> following directions.

Can't get specific right now but when I do modify mine, I will try
to document it on the web.

-- 
André Majorel <URL:http://www.teaser.fr/~amajorel/>
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