Hello Sophie.

Well, is it simply the terms used that you don't quite get, like VCO, VCF, FM, and such
Or is it what the result of those mods would be
Or maybe a combination of the two

Let's take them one by one:

1-VCO -> Cutoff FM

Would take the output of the oscillators, and control the frequency of the filter cutoff. That would result in FM (audio frequency modulation) of the filter. The equivalent of turning the cutoff knob really really fast.

2-VCO -> VCA FM

Same principle, but controlling the volume instead of the filter cutoff. (actually that would be technically called AM, not FM, for amplitude modulation)

3-VCO1 -> VCO(x) FM

Taking the output of oscillator 1 to control the pitch of other oscillators. Frequency modulating other VCOs. (Like you can already do now with MG1 controlling the pitch but much, much faster)

4-LFO speeds increase by adding caps

Getting faster speeds from MG1 or MG2 by adding, or better yet changing values of, timing capacitors (or resistors) in the electronic circuits that compose those LFOs. Which ones
Well to know that, you have to have some technical knowledge or background in electronics.

5- Audio in -> VCF/VCA

Add a connector to allow external signals (other synths, electric guitar, etc...) to pass through the filter (VCF), or final amp (VCA) for using the MP as an "effect" box.

6-Suboscillators via divide circuit to every square

Build additional circuits to effectively add sub-oscillators (oscillators playing one or more octave bellow the source) to each of the square wave output of the oscillators.


Hope this helps a little...


Alain.

--- In korg_mono-poly@yahoogroups.com , Sophie Caroline Bernhard <sophiebernhard@...> wrote:
>
> Hi Johan, Alain and all,
>
> I have to admit it, I am a littler lost with modifications
>
> Where could I get some infos to understand better about those
> modifications Johan wants to make
> Is there a book, a course (a secret potion)
>
> Many thanks in advance for your time in this
>
> Sophie
>
>
>
> On 11 Feb 2010, at 21:51, "Alain" <hubertalain@...> wrote:
>
> > Good mod choices, Johan.
> > I like the CHD Elektro MIDI retrofit better than the Mungo. It's a
> > bit more expensive, but comes already complete and is a more elegant
> > solution for the MP. But that's only my personal opinion.
> >
> > A word of advice,if I may. When dealing with mods that concern the
> > VCOs, extra care must be taken, as those SSM2033 are close to
> > impossible to find as replacement chips, if ever a mod destroys one
> > (or more) of them.
> >
> > For this reason, I'd suggest starting with the filter mods. If ever
> > you inadvertently destroy the SSM2044, there are plenty available
> > (and inexpensive) on Ebay to replace it. Moreover, it is in a DIP
> > socket for easy removal. The SSM2033 are also in a socket, but have
> > their Tempco resistors glued on them and soldered to the main pcb.
> >
> > The LFO speed increase is entirely feasible, but also be aware that
> > doing so to MG2 might not trigger the arpeggiator correctly passed a
> > certain speed (cpu interrupt timing limitation).
> >
> > Sub-osc via divide is a great idea to get a little more "meat" out
> > of the low end.
> >
> > Do you have any schematics to start with, or are you going to
> > engineer them from scratch
> >
> > Alain.
> >
> > --- In korg_mono-poly@yahoogroups.com , "JohanI" <johan.inkinen@>
> > wrote:
> > >
> > > Hi everyone! Thanks for the welcome! :)
> > >
> > > Well I've been thinking of doing these mods:
> > >
> > > VCO->Cutoff FM
> > > VCO->VCA FM
> > > VCO1->VCO(x) FM
> > > LFO speeds increase by adding caps
> > > Audio in -> VCF/VCA
> > > Suboscillators via divide circuit to every square
> > >
> > > Oh, and also adding midi, either via Mungo Enterprises Midi
> > Retrofit or this one : http://www.chd-el.cz/index.php id=409
> > >
> > > I consider myself a beginner in synthmodding, have done a couple
> > on the korg poly800 (moog slayer, 12/24db filterswitch, fm800 and so
> > on) and siel exp80 (similar architecture as poly800). Also working
> > on fitting the Mungo Enterprises midikit in a Juno6 atm.
> > >
> > >
> > >
> > > --- In korg_mono-poly@yahoogroups.com , "Alain" <hubertalain@> wrote:
> > > >
> > > > Yes Johan, welcome!
> > > >
> > > > I've already done a simple mod on mine, to convert arpeggiator
> > trigger input from s-trigger to pulse.
> > > > I also plan to add a sample-and-hold with the clock source as
> > either MG1 or MG2...
> > > >
> > > > Tell us what you want to mod on your MP!
> > > >
> > > > Alain.
> > > >
> > > >
> > > > --- In korg_mono-poly@yahoogroups.com , Florian Anwander
> > <fanwander@> wrote:
> > > > >
> > > > > Hello Johan,
> > > > >
> > > > > welcome to the group!
> > > > >
> > > > > Comment from new user:
> > > > > > hello. i would like to do some modifications on my mp and
> > come here
> > > > > > for help...
> > > > >
> > > > > Let us know what you want to modify.
> > > > >
> > > > > Florian
> > > > >
> > > >
> > >
> >
> >
>