Korg Poly 800 Oscillators

[Harry Bissell]

I think they used a dac to set the current source of a VCO,  then hard sync with
a CPU output... any error shows up as amplitude, not frequency...

but it IS very digital

H^)

patchell wrote:

>     I am now looking at the Poly 800 schematic.  My impressions were wrong, for
> sure.
>
>     The VCO seems to be a chip labled MSM5232.  It has 8 inputs that come from
> a D/A converter and Sample Hold.  So off hand, I would say the pitch is
> controlled by an analog signal.
>
> Glen wrote:
>
> > Hi,
> >
> > I know that the Korg Poly 800 used digitally controlled oscillators, but
> > does anyone know what sort of DCO's these really are? Some companies have
> > used the "DCO" phrase to refer to wavetable digital oscillators (which are
> > really pure digital - not digitally controlled analog.) Other companies
> > have actually built analog oscillators and then used a microprocessor to
> > control them. I would consider the  oscillators in a Gleeman Pentaphonic or
> > an Arp Chroma Polaris to be of this type. Both of these instruments can
> > tune themselves.
> >
> > So does anyone know what style of DCO is in the Korg?
> >
> > Thanks,
> > Glen Berry
>
> --
>  -Jim
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