[sdiy] KorgMS20 mods? help?

[dj hohum]

On 7/31/07, peter edwards <synth at casperelectronics.com> wrote:
> Greg and Daryl,
> Thanks for the feedback. I understand where both of you are coming
> from. I'm not so concerned with the money value of the MS.
>   It's in great condition functionally, but it has some body damage
> that has probably already devalued it a bunch.
>   And this may be short sited, but I really don't ever plan on
> selling it.
> I have a whole bunch of Ken Stone's and Ray Wilson's kits. I'm slowly
> building a big modular using these boards and a few custom built ones
> (very simple).
> My understanding of the MS though is that there are a bunch of
> incompatibilities with modular synth standards.

I'll let the experts chime in here, but, I'm not convinced that's the
case. The supply rails are +-15 and everything seems to have standard
inputs and outputs.  Note on the schematic that many, if not all, of
the mod sources  are restricted to 0 to 5v.Many look quite simple,
like the LFO for instance. I'd start there, you can't go wrong by
cloning what's already there.

I have to say though, popping parts now and again is part of the game.
It happens when you experiment. Just start cautiously and be prepared
to fix things if you overstep your bounds so to speak. The great thing
about the MS-20 is there aren't many (any?) hard to get parts. I can't
find anything on the schematic that isn't pretty bog standard. A few
awkward op-amps maybe, but nothing difficult. Hey, I'd never really
looked at the ms schematics very closely, it's a very clone-able
machine!

daryl


> -pete
>
> On Jul 28, 2007, at 5:34 PM, dj hohum wrote:
>
> > While I think all of those mods are great and I could hardly be called
> > a purist, unless those mods are well done you will certainly devalue
> > your instrument. Fortunately or unfortunately depending on one's
> > perspective, the MS-20 is one of those instruments that's worth quite
> > a bit more when in original shape.
> >
> > I think greg's advice is solid. If you haven't done things like that
> > before then starting on an MS-20 is a risky move. Alternatively,
> > another way to pick up skills and additional modules at the same time
> > is to build a small companion modular from kits, or, even better, just
> > circuit boards. I can highly recommend Ken Stone's boards. Building
> > his boards is relaxing like building a kit but with enough room for
> > deviation that it doesn't become boring. If you want everything in the
> > bag for you then both blacet and paia give you everything you need
> > down to the power cable. While I prefer the blacet build quality I'd
> > have to give the nod to paia in terms of beginner appeal.
> >
> > The thing to get from building is not necessarily just the process of
> > building, rather, it's to understand how to do the mods that you're
> > asking for without worrying about frying things. Adding an LFO, for
> > example, is trivial. You only need to connect it to the power supply
> > and drill holes.
> >
> > But, if you really want to go for it, here's some of what you asked
> > for:
> >
> > http://www.korganalogue.net/korgms/service/ms20/m20s.html
> >
> > daryl
> >
> >
> >
> > On 7/27/07, peter edwards <synth at casperelectronics.com> wrote:
> >> I see that there's been a fair amount of discussion in this group
> >> concerning the Korg MS20 (great rebuild by Julian btw!! http://
> >> www.port23.co.uk/ms20/) so I hope this isn't a tired topic......
> >> I've owned an MS20 for about 7 years now and haven't had a single
> >> problem. What a great synth! 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 love this synth and would hate to fry it so I'm
> >> taking the cautious approach and looking to those with more
> >> experience than I for some pointers.
> >> I'm interested in adding some controls like a pulse width CV input as
> >> well as further patching options like ring mod inputs and an EXT in
> >> mixer. 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 suspect that it would be more trouble
> >> than it's worth.
> >> Anyone out there with some experience who could give me some advice,
> >> schematics, links, etc...
> >> I'm not a pro, but I've got some experience and I'm real good at
> >> following directions.
> >> Thanks!!
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