Archive of the former Yahoo!Groups mailing list: Discussion about the Korg PolySix synthesizer

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Subject: Re: Notes go out of pitch

From: "Peter Andersson" <peter.peppe.andersson@home.se>
Date: 2004-01-21

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
> >>>
> >>>
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> >>>
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> >>>
> >>>
> >>>
> >
> >
> >
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> >
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> >
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