I did the Noise Level mod this past weekend. Basically all I did was
replace the 1 meg ohm trimmer (VR3) on the board with a 1meg pot
mounted on the top panel. Through about half of its range this sounds
good turning up the noise level as the resistance increases (remember
it's in the feedback loop of the op-amp.) Then after 50% a monotone
alias creeps in that is totally out of tune with the note being
played and it sounds terrible. This is most likely the 5223 op-amp
going into oscillation. I plan on inserting a capacitor or maybe even
a choke to eliminate the undesirable frequencies creating this
oscillation to clean up this op-amp's feedback loop. More fun!!!
So far I've done the resonance, cutoff, 12/24db filter switch, FM
feedback mod, and the digital delay clock for my Poly-800 II. I'm
very pleased with the results of these mods to say the least. Now to
clean up the noise level control and this beast is set.....
Fran
--- In korgpolyex@yahoogroups.com, "narfman96" <narfman96@...> wrote:
>
> Hi Brian,
> Glad you're still here, time has been flyin' by for me because it's
our
> busy time of year so I know what you mean.
> I didn't find out anything other than I had mine apart to look over
the
> 2 areas for these mods. I was going to do these mods this past
weekend
> but it was hot and the grankids wanted to go swimming. Maybe this
> weekend I'll get into it and document everything.
>
> I am still looking for the schematics or service docs for the Poly-
800
> II. There doesn't seem to be that much interest here in these Mark
II
> mods. Is there anywhere else to look or am I just too late for the
Poly-
> 800 bandwagon????
>
> More patches is great! I wrote the ones I posted before I did the
mods
> so they need some tweaking to use the "MS" pots effectively.
>
> I'll let you know when I get more info, Fran
>
> --- In korgpolyex@yahoogroups.com, "BRIAN" <walesparry@> wrote:
> >
> > >Hi Fran, sorry to take so long to respond.Did you find out if
the
> > white noise VR-3 mod is similar to the VR-5 or VR_2 mod? Also do
you
> > have a detailed schematic for the delay mod on VR-3 delay board.
> Thanks
> > again for all the help.Ive been programing some Poly 800 sounds
just
> > for the moogslayer mod and will post em when i finsh a full
> bank.These
> > will be for headphones and the brave souls only.
> > BRIAN and WALES
> >
>