Discussion about the Korg PolySix synthesizer

That is the most common notation.  Some countries use a .  some use a , but it all makes sense when you replace both with the value.

4k7 is 4.7k or... 4,7k (europe?)

> ----- Original Message -----
> From: "sdlarch1" <sdlarch@gmail.com>
> To: PolySix@yahoogroups.com
> Subject: [PolySix] Re: Notes go out of pitch
> Date: Tue, 08 Aug 2006 02:10:13 -0000
> 
> 
> I'm not familiar with the resistor value notation used here.
> What are 4k7 and 1k2?  4.7k?  47k?
> 
> 
> --- In PolySix@yahoogroups.com, "Peter Andersson"
> <peter.peppe.andersson@...> wrote:
> >
> >
> > Hi,
> >
> > I wanted to let you know that I've finally managed to repair my 
> > Precious (Polysix). It was indeed the opto resistor, the PC-1, 
> > that was faulty. It was suggested to me that I replace the old
> mysterious
> > PC-1 component with a VTL5C3 and change R93 from 4k7 to 1k2 (to 
> > get the VTL5C3 working properly). I did and then the synth was as 
> > good as new!
> >
> > Appearently, the PC-1 is what stabilizes the expo-converter
> circuit.
> > If it's broken, the circuit can't manage to keep the synth in 
> > tune as the voltages vary (which is especially noticeable during 
> > the
> time
> > the machine is warming up).
> >
> > Thanks for the help!
> >
> >   Peter
> >
> > --- In PolySix@yahoogroups.com, Johannes Hausensteiner <jo.synth@c...> wrote:
> > > I would not start to replace all components; I would rather try
> > > to find out the faulty one. Heat up the whole area of the PCB
> > > using a hot fan. Then you can selectively cool down single
> > > components with cooling spray. If you start the Arpeggiator
> > > before you can let play the Polysix for its own and hear changes
> > > immediately.
> > > > Johannes
> > > > > Peter Andersson wrote:
> > > > You're right, searching for "2SC1583" does give me a bunch of 
> > > > interesting matches. No seller in Sweden but there are shops 
> > in > > Germany, for example, selling both that and the 2SA733. 
> > I'll
> ask
> > a > > friend to get them and post them to me. Like you say, the 
> > opto > > resistor (PC-1) could be tough to get hold of, though. 
> > I'll start by > > replacing the transistors anyway and see if 
> > that does anything. Oh, > > and what about those amplifier ICs? 
> > Is that a long shot you think? > > > > Peter
> > > > > > --- In PolySix@yahoogroups.com, Johannes Hausensteiner > 
> > > <jo.synth@c...> wrote:
> > > > > >>I read from the schematic:
> > > >>* Q12 is a dual npn transistor, common emitter.
> > > >>   The used type is 2SC1583.
> > > >>   I found a company Dönberg Electronics, who does sell this
> > > >>   component, by entering "2sc1583" into Google
> > > >>
> > > >>* Q3 is a standard (Japanese) pnp small signal transistor,
> > > >>   type 2SA733. Dönberg also do have this one or you can take
> > > >>   a BC557 as a substitute. But be careful, the pinout is
> > > >>   different:
> > > >>                  2SA733          BC557
> > > >>                   B-C-E          E-B-C
> > > >>
> > > >>* PC-1 seems to be a Korg custom component. Doesnt it have a
> > > >>   black rubber tube on it? It is drawn in the schematics as
> > > >>   an LED optically coupled to an LDR. Hm.
> > > >>   Maybe someone of the list has a spare?
> > > >>
> > > >>Johannes
> > > >>
> > > >>
> > > >>
> > > >>Peter Andersson wrote:
> > > >>
> > > >>>Wow, that's very useful info! Thanks Johannes!
> > > >>>
> > > >>>The control voltage must be crucial for the expo conversion 
> > to > > > > work > > > >>>properly then. If any of the amplifier 
> > circuits would be
> broken
> > > >>>(IC17, 18 or 19), could that cause this behaviour do you
> think,
> > > > > > or > > > >>>would that just make everything fail "from start"?
> > > >>>
> > > >>>Well, speaking of which... The synth no longer tunes up > > 
> > > > correctly > > > >>>after 20 minutes. Now the tuning and the 
> > note intervals are > > > > screwed > > > >>>up period. So 
> > whatever needed "warming up" a few days ago
> seems
> > > > > > to > > > >>>have failed permanently now.
> > > >>>
> > > >>>I just went over the soldering points around the components
> you
> > > >>>pointed out and resoldered most of them to be sure. I still
> get
> > > > > > the > > > >>>same problem, though, so I guess it's time 
> > to start replacing > >>>components. I'll definitely try testing 
> > with cooling spray. Good > >>>suggestion! > >>>
> > > >>>BTW, it seems I can replace all components in the expo > > > 
> > > conversion > > > >>>circuitry easily except Q12, Q3 and PC-1. 
> > Can't seem to find > > > > info on > > > >>>these anywhere. You 
> > wouldn't happen to know of components > > > > compatible > > > 
> > >>>to any of these three, would you?
> > > >>>
> > > >>>Peter
> > > >>>
> > > >>>
> > > >>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner > 
> > >>><jo.synth@c...> wrote:
> > > >>>
> > > >>>
> > > >>>>The hold capacitors are C56 in unit0..5. But I do not think 
> > that > > > > it
> > > > > >>>>is the hold capacitors very likey. If it were, not all six voices
> > > >>>>would be affected equally. No, it must be something common.
> If
> > it
> > > >>>>is not the wires to/from KLM-396, then the "expo converter"
> is
> > my
> > > >>>>no.1 candidate. KLM-396 seems to be a part of it. The KBD
> works
> > > >>>>logarithmically; that is going up a certain number of keys (e.g.
> > > >>>>12 for one octave) multiplies the frequency of the generated note
> > > >>>>by a certain factor (times 2 in case of an octave). So the
> KBD
> > CV
> > > >>>>logarithmic by its nature, whereas the oscillators work
> linear;
> > > >>>>that is, the generated frequency changes linearly with the 
> > > > > > control
> > > > > >>>>voltage (e.g 1V gives 1000Hz, 2V give 2000Hz, 3V give 3000Hz, > >>>
> > > >>>etc.).
> > > >>>
> > > >>>
> > > >>>>These two schemes are not compatible to each other but it is > >>>
> > > >>>possible
> > > >>>
> > > >>>
> > > >>>>(and necessary) to convert from one to the other. When converting
> > > >>>
> > > >>>>from logarithmic to linear you have to do the opposite of > 
> > > > > logarithm
> > > > > >>>>which is exponential function. It happens that diodes and > >>>
> > > >>>transistors
> > > >>>
> > > >>>
> > > >>>>have exponential transfer curves, so they can be used for this
> > > >>>>purpose. But the exponential function is extrem sensitive 
> > to > > > > small
> > > > > >>>>variations; a small variation of the input causes a big
> change
> > at
> > > >>>>the output. Furthermore the human ear is very sensitive to 
> > > > > > changes
> > > > > >>>>in pitch. This means that there must be taken special
> measures
> > > > > > that
> > > > > >>>>the whole thing does not run out of tune.
> > > >>>>The expo converter in the Polysix is made of IC17, 18, and
> 19,
> > > > > > Q12
> > > > > >>>>(the expo component), PC-1 (kind of an opto-coupling device), Q3,
> > > >>>>and surrounding components. In case of "old production" units
> > > >>>>KLM-396 belong to this circuitry, too. Polysix has 6 voices
> but
> > > >>>>the analog (de)multiplexers for the CV have 8 inputs/outputs. The
> > > >>>>additional 2 inputs/outputs are used for some kind of calibrating
> > > >>>>the exp. amplifier and thus stabilizing tuning of the instrument.
> > > >>>>I am not 100% sure how this works as the CPU never measures
> any
> > > >>>>value and therefore cannot adjust to changing values. From what I
> > > >>>>can see from the code there is always the value 0 ouput > > 
> > > > to "voices"
> > > > > >>>>6 and 7.
> > > >>>>
> > > >>>>According to what you tell, it may be a thermal problem. So 
> > I > > > > would
> > > > > >>>>carefully check all solder points and try to heat up / cool down
> > > >>>>the PCB in the area where these components are located. With > >>>
> > > >>>cooling
> > > >>>
> > > >>>
> > > >>>>spray you may identify a faulty component.
> > > >>>>
> > > >>>>Johannes
> > > >>>>
> > > >>>>
> > > >>>>Peter Andersson wrote:
> > > >>>>
> > > >>>>
> > > >>>>>Yes, it's an old production unit alright. I've checked the 
> > > > > > wires > > > >>>>>between the 366 and the 396. It seems 
> > ok, the solder joints too.
> > > >>>>>
> > > >>>>>Can you tell me which major components are actually involved in > >>>
> > > >>>the > >>>
> > > >>>
> > > >>>>>lin/log conversion/tuning? I've been told to "check" the key > >>>
> > > >>>voltage > >>>
> > > >>>
> > > >>>>>selector chip, the DAC and the S/H capacitors as well as > >>>
> > > >>>something > >>>
> > > >>>
> > > >>>>>called an expo converter. (I don't understand half of this 
> > > > > > stuff > > > >>>to > >>>
> > > >>>
> > > >>>>>be honest - I know you're not surprised. I'm learning, > > 
> > > > though... > > > >>>>>quickly!). These are some of the key 
> > components of the 366
> as
> > > >>>
> > > >>>far as > >>>
> > > >>>
> > > >>>>>I understand. Do they handle the conversion/tuning you're > >>>
> > > >>>refering > >>>
> > > >>>
> > > >>>>>to? I thought I'd start out by replacing the S/H 
> > capacitors. > > > > The > > > >>>>>cheapest and easiest operation 
> > to start with, I thought. > >>>
> > > >>>However, I > >>>
> > > >>>
> > > >>>>>haven't even been able to locate them. It's nearly impossibe to > >>>
> > > >>>read > >>>
> > > >>>
> > > >>>>>the numbers on the 366 schematics I got off the Old Crow web > >>>
> > > >>>site. > >>>
> > > >>>
> > > >>>>>(Man what a fantastic resource his site is, btw!).
> > > >>>>>
> > > >>>>>Again, thanks for helping!
> > > >>>>>
> > > >>>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner > 
> > >>>>><jo.synth@c...> wrote:
> > > >>>>>
> > > >>>>>
> > > >>>>>>From what you tell I would say it is a problem on the KLM-
> > 366, > >>>
> > > >>>in
> > > >>>
> > > >>>
> > > >>>>>>the log/lin conversion/tuning section.
> > > >>>>>>Or maybe you have one of the rare "old production" units.
> Is
> > > >>>
> > > >>>there
> > > >>>
> > > >>>
> > > >>>>>>a small add-on board "KLM-396" to the KLM-366?
> > > >>>>>>It could be a lose wire (if "old production") and/or a 
> > bad > > > > solder
> > > > > >>>>>>joint.
> > > >>>>>>I can see that you are located in Sweden; maybe you ask Ricard
> > > >>>>>>( http://home.swipnet.se/ricard2/p6index.html ) for technical > >>>
> > > >>>help.
> > > >>>
> > > >>>
> > > >>>>>>Peter Andersson wrote:
> > > >>>>>>
> > > >>>>>>
> > > >>>>>>
> > > >>>>>>
> > > >>>>>>>Actually, tones are quite stable even during the first 20 > >>>>>
> > > >>>>>minutes, but
> > > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>>>>the synth is not in tune generally. Also, an octave is a 
> > > > > > quite > > > >>>>>stable
> > > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>>>>major 7 interval for the first 20 minutes, until 
> > suddenly, > > > > the > > > >>>>>synth
> > > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>>>>goes into tune and then the octave is correct as well.
> I'll
> > > >>>
> > > >>>check
> > > >>>
> > > >>>
> > > >>>>>>>tonight if a single generated tone changes a lot during
> the
> > > >>>>>
> > > >>>>>first 10
> > > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>>>>sec.
> > > >>>>>>>
> > > >>>>>>>All six voices are affected. If I play a chord when it > 
> > > > > suddenly > > > >>>>>slides
> > > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>>>>out of pitch, all notes follow. It actually sounds like
> I'm
> > > >>>>>
> > > >>>>>turning
> > > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>>>>the pitch wheel. (I disconnected the pitch wheel, btw,
> just
> > > > > > to > > > >>>>>be sure
> > > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>>>>it wasn't playing tricks on me).
> > > >>>>>>>
> > > >>>>>>>It is not related to the MG setting and I've played 
> > around > > > > with > > > >>>>>all
> > > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>>>>three - VCA, VCF and VCO. I'm quite sure it's not affected by > >>>
> > > >>>the
> > > >>>
> > > >>>
> > > >>>>>>>waveform setting either (whether I use a saw or a pulse) but > >>>
> > > >>>I'll
> > > >>>
> > > >>>
> > > >>>>>>>double check that tonight. The PWM setting does not make
> any
> > > >>>>>>>difference.
> > > >>>>>>>
> > > >>>>>>>Does this give you any clues? Thanks for helping!
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner > >>>>>
> > > >>>>><jo.synth@c...>
> > > >>>>>
> > > >>>>>>>wrote:
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>>It is not normal that it takes 20 miuntes to tune up. > 
> > > > > Usually > > > >>>it
> > > >>>
> > > >>>
> > > >>>>>>>>takes about 10sec to tune and then it is quite stable.
> > > >>>>>>>>Check the following: hold a key down when switching 
> > power > > > > on. > > > >>>The
> > > >>>
> > > >>>
> > > >>>>>>>>generated note should change quite a lot until it 
> > stabilizes > >>>>>
> > > >>>>>after
> > > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>>>>>a few secs.
> > > >>>>>>>>Are all six voice affected? Is the effect related to the MG > >>>>>
> > > >>>>>setting
> > > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>>>>>(VCA/VCF/VCO)? Is it related to PWM setting?
> > > >>>>>>>>
> > > >>>>>>>>
> > > >>>>>>>>Peter Andersson wrote:
> > > >>>>>>>>
> > > >>>>>>>>
> > > >>>>>>>>
> > > >>>>>>>>
> > > >>>>>>>>
> > > >>>>>>>>>Hi all,
> > > >>>>>>>>>
> > > >>>>>>>>>I'm the proud new owner of a Polysix. I love it! Can't 
> > take > > > > my
> > > > > >>>>>>>hands > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>>>off those knobs - the filters are just great! But I'm 
> > > > > > having > > > >>>a > >>>
> > > >>>
> > > >>>>>>>>>problem with it and I'm hoping someone can tell me what it's
> > > >>>>>>>
> > > >>>>>>>about > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>>>and maybe even what can be done...
> > > >>>>>>>>>
> > > >>>>>>>>>After I've played the synth for a while, notes start to go > >>>
> > > >>>out > >>>
> > > >>>
> > > >>>>>of > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>>>>>>pitch every now and then. It happens randomly every 10-
> 30
> > > > > > sec > > > >>>or
> > > >>>
> > > >>>
> > > >>>>>>>so. > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>>>The notes go off pitch with a note or so and always 
> > jump or > >>>>>
> > > >>>>>slide > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>>>>>>back to the original pitch again within half a second.
> > > >>>>>>>>>
> > > >>>>>>>>>At first I thought it was some filter setting of mine that > >>>>>
> > > >>>>>caused > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>>>>>>it, but as it turns out I get this no matter how the 
> > Poly6 > > > > is > > > >>>>>>>>>programmed (or if I use a preset 
> > or a fresh "manual" > > > > sound). > > > >>>(By
> > > >>>
> > > >>>
> > > >>>>>>>the > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>>>way, it takes about 20 minutes for the unit to get in 
> > > > > > perfect
> > > > > >>>>>>>tune > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>>>after a cold start. Don't know if that's normal or if
> it's
> > > >>>>>>>
> > > >>>>>>>related > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>>>to this problem in any way).
> > > >>>>>>>>>
> > > >>>>>>>>>I'd be truly grateful for any help!
> > > >>>>>>>>>
> > > >>>>>>>>>Peter
> > > >>>>>>>>>
> > > >>>>>>>>>
> > > >>>>>>>>>
> > > >>>>>>>>>
> > > >>>>>>>>>PolySix "Digiest" Page: 
> > http://www.acc.umu.se/~amber/Poly6 > >>>>>>>>>
> > > >>>>>>>>>
> > > >>>>>>>>>Yahoo! Groups Links
> > > >>>>>>>>>
> > > >>>>>>>>>To visit your group on the web, go to:
> > > >>>>>>>>>http://groups.yahoo.com/group/PolySix/
> > > >>>>>>>>>
> > > >>>>>>>>>To unsubscribe from this group, send an email to:
> > > >>>>>>>>>PolySix-unsubscribe@yahoogroups.com
> > > >>>>>>>>>
> > > >>>>>>>>>Your use of Yahoo! Groups is subject to:
> > > >>>>>>>>>http://docs.yahoo.com/info/terms/ > >>>>>>>>>
> > > >>>>>>>>>
> > > >>>>>>>>>
> > > >>>>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 > >>>>>>>
> > > >>>>>>>Yahoo! Groups Links
> > > >>>>>>>
> > > >>>>>>>To visit your group on the web, go to:
> > > >>>>>>>http://groups.yahoo.com/group/PolySix/
> > > >>>>>>>
> > > >>>>>>>To unsubscribe from this group, send an email to:
> > > >>>>>>>PolySix-unsubscribe@yahoogroups.com
> > > >>>>>>>
> > > >>>>>>>Your use of Yahoo! Groups is subject to:
> > > >>>>>>>http://docs.yahoo.com/info/terms/ > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>>PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 > >>>>>
> > > >>>>>Yahoo! Groups Links
> > > >>>>>
> > > >>>>>To visit your group on the web, go to:
> > > >>>>>http://groups.yahoo.com/group/PolySix/
> > > >>>>>
> > > >>>>>To unsubscribe from this group, send an email to:
> > > >>>>>PolySix-unsubscribe@yahoogroups.com
> > > >>>>>
> > > >>>>>Your use of Yahoo! Groups is subject to:
> > > >>>>>http://docs.yahoo.com/info/terms/ > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>
> > > >>>
> > > >>>
> > > >>>PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 > >>>
> > > >>>
> > > >>>Yahoo! Groups Links
> > > >>>
> > > >>>To visit your group on the web, go to:
> > > >>> http://groups.yahoo.com/group/PolySix/
> > > >>>
> > > >>>To unsubscribe from this group, send an email to:
> > > >>> PolySix-unsubscribe@yahoogroups.com
> > > >>>
> > > >>>Your use of Yahoo! Groups is subject to:
> > > >>> http://docs.yahoo.com/info/terms/ > >>>
> > > >>>
> > > >>>
> > > >>>
> > > > > > > > > > PolySix "Digiest" Page: 
> > http://www.acc.umu.se/~amber/Poly6 > > > > Yahoo! Groups Links
> > > > > > To visit your group on the web, go to:
> > > >  http://groups.yahoo.com/group/PolySix/
> > > > > > To unsubscribe from this group, send an email to:
> > > >  PolySix-unsubscribe@yahoogroups.com
> > > > > > Your use of Yahoo! Groups is subject to:
> > > >  http://docs.yahoo.com/info/terms/ > > > > > > > >
> >
> 
> 
> 
> 
> 
> 
> PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> Yahoo! Groups Links
> 
> 
> 
> 

>



.sig
-Chromatest J. Pantsmaker
http://www.chromatest.net