Korg Poly800/EX800 Users

wondering what a block diagram of this synth
would look like. as in, a kind of signal flow
diagram or something like that.

just wondering about theoretical possibilities
(and impossibilities) for future ideas;
for instance, taking separate harmonics and
rerouting them, ringmod options, stuff like that?

i'd like to know more about what's going on inside,
how it compares,say, to juno's jp's and jx's. some
kind of assessment/description of the osc+filter etc.
circuitry.

Hey,
Which synth do you have exactly? I have the Poly-800II so I can only really speak about it but go to "Files > 3) Poly-800 MKII > User manuals and tips" and get the manual "Poly800II_Manual.pdf". There is a block diagram on page 15 in the PDF file. If you have a different synth I am sure it can not be to much different then what you will find there. Hopefully that will get you started. Also search the other User and Service manuals found here or elsewhere on the web!


Joe

--- In korgpolyex@yahoogroups.com, "k9k9dog" <domgoold@...> wrote:
>
> wondering what a block diagram of this synth
> would look like. as in, a kind of signal flow
> diagram or something like that.
>
> just wondering about theoretical possibilities
> (and impossibilities) for future ideas;
> for instance, taking separate harmonics and
> rerouting them, ringmod options, stuff like that?
>
> i'd like to know more about what's going on inside,
> how it compares,say, to juno's jp's and jx's. some
> kind of assessment/description of the osc+filter etc.
> circuitry.
>

the main difference with the Poly-800 series as opposed to other polysynths of the era is that all eight oscillators are first routed through their own amplifier, and then through a *shared* 4-pole filter. this makes it a unique instrument to play harmonically -- something between a polysynth and a monosynth. all of the other synths you mentioned use the more traditional polysynth architecture which provides each voice it's own filter and amplifier, with the filter before the amplifier. -pc

The principle you mentioned was more common with TOS (organ type) polysynths or enseble keyboards in the 70s, such as the Polymoog or Korg PE Series. later, in the 80s, there were only few designs with shared filter, such as the Korg Mono/Poly. Korg did this design on the 800 mainly for cutting costs. The DW series do have the same VCF chip (NJM2069) but one for each oscillator. Interesting to see the reduction of components. Polysix does use 2 mask programmed MCS48 MCUs while Poly 800 uses one of these MCUs with external ROM.

--- In korgpolyex@yahoogroups.com, Paul Cunningham <paul@...> wrote:
>
> the main difference with the Poly-800 series as opposed to other polysynths of the era is that all eight oscillators are first routed through their own amplifier, and then through a *shared* 4-pole filter. this makes it a unique instrument to play harmonically -- something between a polysynth and a monosynth. all of the other synths you mentioned use the more traditional polysynth architecture which provides each voice it's own filter and amplifier, with the filter before the amplifier. -pc
>
>
> On Feb 14, 2011, at 3:44 PM, k9k9dog wrote:
>
> > wondering what a block diagram of this synth
> > would look like. as in, a kind of signal flow
> > diagram or something like that.
> >
> > just wondering about theoretical possibilities
> > (and impossibilities) for future ideas;
> > for instance, taking separate harmonics and
> > rerouting them, ringmod options, stuff like that?
> >
> > i'd like to know more about what's going on inside,
> > how it compares,say, to juno's jp's and jx's. some
> > kind of assessment/description of the osc+filter etc.
> > circuitry.
> >
> >
>

ok; so single (D)CF, post VCAs. eg, mix pre-filter.then, i guess,
another vca to set output level?

in synthedit, it made sense to share a filter to save cpu on a
recent project, but that was pre vca/pan and mix/level.

interested you say there 8 oscillators, whereas i was suspecting
a single osc, with freq/dividing to produce divisions/harmonics.

so this could suggest independent outputs and operation? detuning?
i find the detuning a bit unimpressive, tbh, just semi's, whereas
somethign finer could really fatten things up a bit. and phasemod
and stuff like that...
hey, i haven't seen/used my ex800 (poly1) for some time, so i forget
a bit. wdf, it has it's own character, within what it has.

i'll look for the stuff you mention, but would like something
'from the horse's mouth', eg this group of interested users,
from the circuit-bending viewpoint, for purpose of discussion.
(i ain't going in there messing things up)

my main reference atm is synthedit, which has allowed me to
experiment with things like phase etc. just means i can plug
things in without breaking anything...

--- In korgpolyex@yahoogroups.com, Paul Cunningham <paul@...> wrote:
>
> the main difference with the Poly-800 series as opposed to other polysynths of the era is that all eight oscillators are first routed through their own amplifier, and then through a *shared* 4-pole filter. this makes it a unique instrument to play harmonically -- something between a polysynth and a monosynth. all of the other synths you mentioned use the more traditional polysynth architecture which provides each voice it's own filter and amplifier, with the filter before the amplifier. -pc
>
>
> On Feb 14, 2011, at 3:44 PM, k9k9dog wrote:
>
> > wondering what a block diagram of this synth
> > would look like. as in, a kind of signal flow
> > diagram or something like that.
> >
> > just wondering about theoretical possibilities
> > (and impossibilities) for future ideas;
> > for instance, taking separate harmonics and
> > rerouting them, ringmod options, stuff like that?
> >
> > i'd like to know more about what's going on inside,
> > how it compares,say, to juno's jp's and jx's. some
> > kind of assessment/description of the osc+filter etc.
> > circuitry.
> >
> >
>

Hi may be you will interested in my drawing Photos section / poly-800 - wiring modification . http://groups.yahoo.com/group/korgpolyex/photos/album/2123369380/pic/199866271/view?picmode=original&mode=tn&order=ordinal&start=1&dir=asc
I promised (but unfortunately haven`t time and mainly space to continue) to make and document some rewiring modifications. And drawing shows basic points ,like signal inputs and outputs for parts (DCOs, VCA..). So there`s needed "just" to take some wire, and conect it here and there... :-)

What I could hear from my Poly800 (except of well known FM-800 and moog slayer):
- audio in - connected to noise transistor - has large gain (distorts sound)
- chorus feedback
- slowed down chorus LFO
- chorus (actually short delay) not driven by LFO , but manually set
- filter cutoff and/or resonance driven by LFO
- DCO2 output bypassed VCF - sound mixed
- FM800 like , but driven by external audio

All mods were just one-time tries, and I don`t have mounted them as permanent options.
But anyway, now ,as I can see this list written together, it`s a shame I didn`t made a documentation+sounds. May be, I will find at least some photos...

Jozef

PS: Zdravim pana Forro-a, este vzdy siahnem po niektorej Vasej knihe.

--- In korgpolyex@yahoogroups.com, "k9k9dog" <domgoold@...> wrote:
>
> ok; so single (D)CF, post VCAs. eg, mix pre-filter.then, i guess,
> another vca to set output level?
>
> in synthedit, it made sense to share a filter to save cpu on a
> recent project, but that was pre vca/pan and mix/level.
>
> interested you say there 8 oscillators, whereas i was suspecting
> a single osc, with freq/dividing to produce divisions/harmonics.
>
> so this could suggest independent outputs and operation? detuning?
> i find the detuning a bit unimpressive, tbh, just semi's, whereas
> somethign finer could really fatten things up a bit. and phasemod
> and stuff like that...
> hey, i haven't seen/used my ex800 (poly1) for some time, so i forget
> a bit. wdf, it has it's own character, within what it has.
>
> i'll look for the stuff you mention, but would like something
> 'from the horse's mouth', eg this group of interested users,
> from the circuit-bending viewpoint, for purpose of discussion.
> (i ain't going in there messing things up)
>
> my main reference atm is synthedit, which has allowed me to
> experiment with things like phase etc. just means i can plug
> things in without breaking anything...
>
>
> --- In korgpolyex@yahoogroups.com, Paul Cunningham <paul@> wrote:
> >
> > the main difference with the Poly-800 series as opposed to other polysynths of the era is that all eight oscillators are first routed through their own amplifier, and then through a *shared* 4-pole filter. this makes it a unique instrument to play harmonically -- something between a polysynth and a monosynth. all of the other synths you mentioned use the more traditional polysynth architecture which provides each voice it's own filter and amplifier, with the filter before the amplifier. -pc
> >
> >
> > On Feb 14, 2011, at 3:44 PM, k9k9dog wrote:
> >
> > > wondering what a block diagram of this synth
> > > would look like. as in, a kind of signal flow
> > > diagram or something like that.
> > >
> > > just wondering about theoretical possibilities
> > > (and impossibilities) for future ideas;
> > > for instance, taking separate harmonics and
> > > rerouting them, ringmod options, stuff like that?
> > >
> > > i'd like to know more about what's going on inside,
> > > how it compares,say, to juno's jp's and jx's. some
> > > kind of assessment/description of the osc+filter etc.
> > > circuitry.
> > >
> > >
> >
>

Michael,

can you give me a hint which components belong to the detune circuit? Is ot IC17/18? I take a look at the schematics but on my 19" monitor I still have no overwiew, think I should get it printed:)

Im remember well the unison detune circuit of my Polysix, it was simple, but clever: an additional 4051 just added switched positive or negative offsets to the osciallator CVs. On the 800 it is a digital circuit I think.

--- In korgpolyex@yahoogroups.com, Michael Hawkins <korgpolyex800@...> wrote:
>
> the detune circuit is just begging for some one to come along and design a much
> more fine tuned detuned.
>
> But, keep in mind that the MSM5232 chip uses two clocks which then feeds into
> the two banks of 4 DCO's.
>
> So if someone comes up with a great detune circuit, it is still only going to
> affect DCO1 to DCO2 detuning. And it won't detune all DCO's.
>
> The four DCO's will still be in pure tune and then the other four DCO's will be
> in perfect tune. The two clocks detuned would at least detune the two pairs of
> DCO's. So that would be great.
>
> Mike.
>
>
>
>
> ________________________________
> From: k9k9dog <domgoold@...>
> To: korgpolyex@yahoogroups.com
> Sent: Tue, February 15, 2011 2:57:30 PM
> Subject: [korgpolyex] Re: the synth architecture
>
>
> ok; so single (D)CF, post VCAs. eg, mix pre-filter.then, i guess,
> another vca to set output level?
>
> in synthedit, it made sense to share a filter to save cpu on a
> recent project, but that was pre vca/pan and mix/level.
>
> interested you say there 8 oscillators, whereas i was suspecting
> a single osc, with freq/dividing to produce divisions/harmonics.
>
> so this could suggest independent outputs and operation? detuning?
> i find the detuning a bit unimpressive, tbh, just semi's, whereas
> somethign finer could really fatten things up a bit. and phasemod
> and stuff like that...
> hey, i haven't seen/used my ex800 (poly1) for some time, so i forget
> a bit. wdf, it has it's own character, within what it has.
>
> i'll look for the stuff you mention, but would like something
> 'from the horse's mouth', eg this group of interested users,
> from the circuit-bending viewpoint, for purpose of discussion.
> (i ain't going in there messing things up)
>
> my main reference atm is synthedit, which has allowed me to
> experiment with things like phase etc. just means i can plug
> things in without breaking anything...
>
> --- In korgpolyex@yahoogroups.com, Paul Cunningham <paul@> wrote:
> >
> > the main difference with the Poly-800 series as opposed to other polysynths of
> >the era is that all eight oscillators are first routed through their own
> >amplifier, and then through a *shared* 4-pole filter. this makes it a unique
> >instrument to play harmonically -- something between a polysynth and a
> >monosynth. all of the other synths you mentioned use the more traditional
> >polysynth architecture which provides each voice it's own filter and amplifier,
> >with the filter before the amplifier. -pc
> >
> >
> > On Feb 14, 2011, at 3:44 PM, k9k9dog wrote:
> >
> > > wondering what a block diagram of this synth
> > > would look like. as in, a kind of signal flow
> > > diagram or something like that.
> > >
> > > just wondering about theoretical possibilities
> > > (and impossibilities) for future ideas;
> > > for instance, taking separate harmonics and
> > > rerouting them, ringmod options, stuff like that?
> > >
> > > i'd like to know more about what's going on inside,
> > > how it compares,say, to juno's jp's and jx's. some
> > > kind of assessment/description of the osc+filter etc.
> > > circuitry.
> > >
> > >
> >
>

what kind of frequencies are involved at these points?
and what are the steps/components that divide down the clock?

saw also that there are outputs for two other 'fundamentals'(?)
at 8' and 16', described as 'rectangle'(is this the same as pulse?)

on a different note, looking at the block diagram, showing
the separate outputs of each tone source, it would seem to
offer the opportunity for cross modulation, such as ringmod,
and some type of FM. (obviously, independent detune comes in
here...). you can get a good range of tx-type sounds with
just two operators/oscillators using audio from one to mod
*phase* on the other, sync/un-sync, with relative detuning.

there could maybe be some kind of variable sync'ing of oscillators?
or are they already sync'd by being run by shared clock?

it's quite a leap; doesn't hurt to talk about it, tho'.

--- In korgpolyex@yahoogroups.com, Michael Hawkins <korgpolyex800@...> wrote:
>
> Detune is based upon IC20 (74HC393), IC19 (74HC151) and logic parts of IC17 and
> IC18.
>
> It is marked on the schematic as section "22" and in the service manual it is
> explained there.
>
> The Poly-800 has one master oscillator. Pitch bend and DCO modulation signals
> are injected into the master oscillator.
>
> The master clock is fed directly into CLK1 on the DCO tone generator (marked on
> the schematic as "K".
>
> The detuned clock takes the master clock as its input source, detunes it and
> then feeds it into CLK2 on the DCO tone generator. Marked as "J".
>
> Mike
>
>
>
>
> ________________________________
> From: microbugix <springmauser@...>
> To: korgpolyex@yahoogroups.com
> Sent: Sat, February 19, 2011 6:21:46 PM
> Subject: [korgpolyex] Re: the synth architecture
>
>
> Michael,
>
> can you give me a hint which components belong to the detune circuit? Is ot
> IC17/18? I take a look at the schematics but on my 19" monitor I still have no
> overwiew, think I should get it printed:)
>
> Im remember well the unison detune circuit of my Polysix, it was simple, but
> clever: an additional 4051 just added switched positive or negative offsets to
> the osciallator CVs. On the 800 it is a digital circuit I think.
>
> --- In korgpolyex@yahoogroups.com, Michael Hawkins <korgpolyex800@> wrote:
> >
> > the detune circuit is just begging for some one to come along and design a much
> >
> > more fine tuned detuned.
> >
> > But, keep in mind that the MSM5232 chip uses two clocks which then feeds into
> > the two banks of 4 DCO's.
> >
> > So if someone comes up with a great detune circuit, it is still only going to
> > affect DCO1 to DCO2 detuning. And it won't detune all DCO's.
> >
> > The four DCO's will still be in pure tune and then the other four DCO's will be
> >
> > in perfect tune. The two clocks detuned would at least detune the two pairs of
>
> > DCO's. So that would be great.
> >
> > Mike.
> >
> >
> >
> >
> > ________________________________
> > From: k9k9dog <domgoold@>
> > To: korgpolyex@yahoogroups.com
> > Sent: Tue, February 15, 2011 2:57:30 PM
> > Subject: [korgpolyex] Re: the synth architecture
> >
> >
> > ok; so single (D)CF, post VCAs. eg, mix pre-filter.then, i guess,
> > another vca to set output level?
> >
> > in synthedit, it made sense to share a filter to save cpu on a
> > recent project, but that was pre vca/pan and mix/level.
> >
> > interested you say there 8 oscillators, whereas i was suspecting
> > a single osc, with freq/dividing to produce divisions/harmonics.
> >
> > so this could suggest independent outputs and operation? detuning?
> > i find the detuning a bit unimpressive, tbh, just semi's, whereas
> > somethign finer could really fatten things up a bit. and phasemod
> > and stuff like that...
> > hey, i haven't seen/used my ex800 (poly1) for some time, so i forget
> > a bit. wdf, it has it's own character, within what it has.
> >
> > i'll look for the stuff you mention, but would like something
> > 'from the horse's mouth', eg this group of interested users,
> > from the circuit-bending viewpoint, for purpose of discussion.
> > (i ain't going in there messing things up)
> >
> > my main reference atm is synthedit, which has allowed me to
> > experiment with things like phase etc. just means i can plug
> > things in without breaking anything...
> >
> > --- In korgpolyex@yahoogroups.com, Paul Cunningham <paul@> wrote:
> > >
> > > the main difference with the Poly-800 series as opposed to other polysynths
> >of
> >
> > >the era is that all eight oscillators are first routed through their own
> > >amplifier, and then through a *shared* 4-pole filter. this makes it a unique
> > >instrument to play harmonically -- something between a polysynth and a
> > >monosynth. all of the other synths you mentioned use the more traditional
> > >polysynth architecture which provides each voice it's own filter and
> >amplifier,
> >
> > >with the filter before the amplifier. -pc
> > >
> > >
> > > On Feb 14, 2011, at 3:44 PM, k9k9dog wrote:
> > >
> > > > wondering what a block diagram of this synth
> > > > would look like. as in, a kind of signal flow
> > > > diagram or something like that.
> > > >
> > > > just wondering about theoretical possibilities
> > > > (and impossibilities) for future ideas;
> > > > for instance, taking separate harmonics and
> > > > rerouting them, ringmod options, stuff like that?
> > > >
> > > > i'd like to know more about what's going on inside,
> > > > how it compares,say, to juno's jp's and jx's. some
> > > > kind of assessment/description of the osc+filter etc.
> > > > circuitry.
> > > >
> > > >
> > >
> >
>

Although I may be a bit late to the party, I like to share my idea about this topic:)

Best thing you can do here is replacing all the discrete components with one but programmable chip: an FPGA. I think there are small ones out there, but they will allow to do nearly everything you want with the clock signal. Just take a look at http://www.fpga4fun.com/index.html or fpgacentral.com, there are many resources for these things.

There is a bit of learning curve to master this chips, but you can do many things with it if you are willing to do:)

--- In korgpolyex@yahoogroups.com, Michael Hawkins <korgpolyex800@...> wrote:
>
> Detune is based upon IC20 (74HC393), IC19 (74HC151) and logic parts of IC17 and
> IC18.
>
> It is marked on the schematic as section "22" and in the service manual it is
> explained there.
>
> The Poly-800 has one master oscillator. Pitch bend and DCO modulation signals
> are injected into the master oscillator.
>
> The master clock is fed directly into CLK1 on the DCO tone generator (marked on
> the schematic as "K".
>
> The detuned clock takes the master clock as its input source, detunes it and
> then feeds it into CLK2 on the DCO tone generator. Marked as "J".
>
> Mike
>
>
>
>
> ________________________________
> From: microbugix <springmauser@...>
> To: korgpolyex@yahoogroups.com
> Sent: Sat, February 19, 2011 6:21:46 PM
> Subject: [korgpolyex] Re: the synth architecture
>
>
> Michael,
>
> can you give me a hint which components belong to the detune circuit? Is ot
> IC17/18? I take a look at the schematics but on my 19" monitor I still have no
> overwiew, think I should get it printed:)
>
> Im remember well the unison detune circuit of my Polysix, it was simple, but
> clever: an additional 4051 just added switched positive or negative offsets to
> the osciallator CVs. On the 800 it is a digital circuit I think.
>
> --- In korgpolyex@yahoogroups.com, Michael Hawkins <korgpolyex800@> wrote:
> >
> > the detune circuit is just begging for some one to come along and design a much
> >
> > more fine tuned detuned.
> >
> > But, keep in mind that the MSM5232 chip uses two clocks which then feeds into
> > the two banks of 4 DCO's.
> >
> > So if someone comes up with a great detune circuit, it is still only going to
> > affect DCO1 to DCO2 detuning. And it won't detune all DCO's.
> >
> > The four DCO's will still be in pure tune and then the other four DCO's will be
> >
> > in perfect tune. The two clocks detuned would at least detune the two pairs of
>
> > DCO's. So that would be great.
> >
> > Mike.
> >
> >
> >
> >
> > ________________________________
> > From: k9k9dog <domgoold@>
> > To: korgpolyex@yahoogroups.com
> > Sent: Tue, February 15, 2011 2:57:30 PM
> > Subject: [korgpolyex] Re: the synth architecture
> >
> >
> > ok; so single (D)CF, post VCAs. eg, mix pre-filter.then, i guess,
> > another vca to set output level?
> >
> > in synthedit, it made sense to share a filter to save cpu on a
> > recent project, but that was pre vca/pan and mix/level.
> >
> > interested you say there 8 oscillators, whereas i was suspecting
> > a single osc, with freq/dividing to produce divisions/harmonics.
> >
> > so this could suggest independent outputs and operation? detuning?
> > i find the detuning a bit unimpressive, tbh, just semi's, whereas
> > somethign finer could really fatten things up a bit. and phasemod
> > and stuff like that...
> > hey, i haven't seen/used my ex800 (poly1) for some time, so i forget
> > a bit. wdf, it has it's own character, within what it has.
> >
> > i'll look for the stuff you mention, but would like something
> > 'from the horse's mouth', eg this group of interested users,
> > from the circuit-bending viewpoint, for purpose of discussion.
> > (i ain't going in there messing things up)
> >
> > my main reference atm is synthedit, which has allowed me to
> > experiment with things like phase etc. just means i can plug
> > things in without breaking anything...
> >
> > --- In korgpolyex@yahoogroups.com, Paul Cunningham <paul@> wrote:
> > >
> > > the main difference with the Poly-800 series as opposed to other polysynths
> >of
> >
> > >the era is that all eight oscillators are first routed through their own
> > >amplifier, and then through a *shared* 4-pole filter. this makes it a unique
> > >instrument to play harmonically -- something between a polysynth and a
> > >monosynth. all of the other synths you mentioned use the more traditional
> > >polysynth architecture which provides each voice it's own filter and
> >amplifier,
> >
> > >with the filter before the amplifier. -pc
> > >
> > >
> > > On Feb 14, 2011, at 3:44 PM, k9k9dog wrote:
> > >
> > > > wondering what a block diagram of this synth
> > > > would look like. as in, a kind of signal flow
> > > > diagram or something like that.
> > > >
> > > > just wondering about theoretical possibilities
> > > > (and impossibilities) for future ideas;
> > > > for instance, taking separate harmonics and
> > > > rerouting them, ringmod options, stuff like that?
> > > >
> > > > i'd like to know more about what's going on inside,
> > > > how it compares,say, to juno's jp's and jx's. some
> > > > kind of assessment/description of the osc+filter etc.
> > > > circuitry.
> > > >
> > > >
> > >
> >
>