Korg Poly800/EX800 Users

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.
> > > > 
> > > >
> > >
> >
>