Hi David. You're talking about the Korg MS-04 expression pedal that was offered back in the days of the MS-10 and MS-20 synths. Yes, that would be a great pedal to use with the MP4 ! Now, the only thing is to find one, and be prepared to spend a fair amount to get it.
I suppose we can always modify a Moog EV-5 or Roland EP-2 or Korg EXP-2 to add an LFO to them and power them with two 9V batteries

Alain.

--- In korg_mono-poly@yahoogroups.com , David Kyle <sammydvsjr@...> wrote:
>
> Korg used to make an expression pedal- if you can find one, you will LOVE IT
> !!!!! it ran on 2 nine volt batteries-
> I used to have one- it offered an LFO mode( with sample and hold! )- hooked
> up to the MP it's a charm-
> you could sweep the filter and/or lfo at the same time !
> I sold mine on ebay 5 yrs ago for 350 usd- which I regret .
>
> D
>
> On Wed, Mar 17, 2010 at 10:34 AM, Alain <hubertalain@...> wrote:
>
> >
> >
> > Hi (put your name here), and welcome to this group.
> >
> > Unfortunately, the Mono/Poly doesn't support expression pedals. There are
> > indeed VCO and VCF frequency control jacks in the back to vary the pitch or
> > filter cutoff. Both those connectors are waiting to receive a voltage from
> > an outside source.
> >
> > An expression pedal, such as the EP-2 From Moog Music and EV-5 from Roland,
> > are just a potentiometer and some wires. Those pedals have a stereo 1/4"
> > plug and are receiving a voltage from the synth, and send back the
> > variations produced by the pot being moved by the foot plate.
> >
> > On the MP4, there is no voltage present at the connectors on the back,
> > except the "CV out" (variable voltage that follows the keyboard notes) and
> > "TRIG out" (very short pulses on each key stroke).
> >
> > What is required for an expression pedal to work is a fixed voltage source.
> > There is the possibility of modifying the Mono/Poly to replace the switched
> > mono "VCF fcM in" connector by a switched stereo one, and routing a fixed
> > voltage source to that. But that would mean tinkering with your beloved
> > synth.
> >
> > So the short answer is: expression pedals will not work on a Korg
> > Mono/Poly, sorry.
> >
> > Alain.
> >
> > --- In korg_mono-poly@yahoogroups.com <korg_mono-poly%40yahoogroups.com>,
> > "suicidesushi82" <jeppe@> wrote:
> > >
> > > Hello everyone.First post here...
> > > Okay so i really want to mod the filter cutoff with som kind of
> > > expression pedal. Does any of you have any experience with this I
> > > bought a pedal from Moog called EP-2 because it was cheap and I figured
> > > it would fit with some CV standard that Mono/Poly used. But it didn't
> > > work. Are any of you useing an expression pedal to modulate the filter
> > > cutoff And which
> > > Thanks a bunch.
> > >
> >
> >
> >
>
>
>
> --
> eat and sleep....TODAY!!!!
>