Howdy,

This filter mod. Is it for the SK-1? 5? 60? or all? Right now, I'm
trying to get all the bending info I can for 3 Sk-5s and 2 SK-60s.
Not to mention coleco talking teacher and various v-tech stuff.
Oh....oh AND a Casio CT-370. That's the one that's lying open on my
table right now, along with an hr-16 and 16B.
Rig


--- In CasioSK@yahoogroups.com, "plutoniq9" <Plutonique9@...> wrote:
>
> It shouldn't affect peak CV voltage. Right now, the four 0.33uf
> capcacitors connected to the individual voice CV out's are used
merely
> to smooth the quantized (8-bit?) envelopes generated by the OKI CPU.
> That is, they have a very fast roll-off...that is what I think the
10k
> resistors are for, fast discharge of the 0.33uf caps. If you
increase
> this value with a potentiometer, maybe like 1M or 2M in series with
> 10k resistor, it should have the effect of decreasing the capacitor
> discharge rates, therefore extending decay time...
>
> Setting the envelope to gate mode (on/off with note key press) would
> give the best results for having 100% control over decay time.
>
> now you got me interested in this..... :)
>
> cya
>
> --- In CasioSK@yahoogroups.com, "gmeredith1" <gmeredith1@> wrote:
> >
> > Hi Ryan,
> >
> > Worth a try. I didn't fool around with any of the components
> > downstream (I inserted the mod directly out from the processor CV
> > lines). Although, if controlling the decay as you mentioned with
> > those components reduces the CV voltage output in some way, it
might
> > be to the detriment of my next mod - the Filterbank VCF mod. It
needs
> > all the CV voltage it can get to open the filters nice and wide,
as
> > the raw CV voltage out from the processor is only 2.5V. It's JUST
> > high enough to open the filters all the way.
> >
> > cheers, Graham
> >
> >
> >
> > --- In CasioSK@yahoogroups.com, "plutoniq9" <Plutonique9@> wrote:
> > >
> > > Hi Graham,
> > >
> > > I haven't MS Word here @ home so I'll have to print out your
mod @
> > > work today so I can see the graphics.
> > >
> > > Looking at the schematics, a few things come to mind;
> > >
> > > -I'm wondering what the 100K resistors are used for that are in
> > > parallel with the diodes just prior to the 0.33uf caps. In a
normal
> > RC
> > > envelope circuit, I'd just expect the diode to be there (to
prevent
> > > reverse discharge). I know the caps are used to "smooth" the
> > quantized
> > > envelope CV's, perhaps they are there to counter the .7v switch
> > on/off
> > > threshold of most silicon diodes? Are they germanium diodes i
> > wonder?
> > > Gotta take a look inside my unit.
> > >
> > > - I can see a 10k resistor going to ground just after the 0.33uf
> > > capacitor charge goes through a 2.2k (for each voice). Seems
that
> > > increasing this value (10k resistor) should extend decay time,
> > perhaps
> > > this may have the desired effect?
> > >
> > > seeya
> > >
> > > ryan
> > >
> >
>