Discussion about the Korg PolySix synthesizer

--- In PolySix@yahoogroups.com, "peterm" <peterm@...> wrote:
>
> Hi,
>
> I have no idea about the temperature, but I recall reading about a PSU replacement for the Kiwisix kit.
> http://kiwitechnics.com/kiwisix.htm
>
> "A number of Polysix's that arrive at our workshop have had extensive damage across multiple boards. It is our conclusion that this has been caused by overvoltage being applied to all the boards. This can only have come from the Power regulating board and because of this we no longer trust the original power regulating circuitry in the Polysix."
>
> It wouldn't surprise me if the original Polysix PSU has little or no margin for additional load.
>
> BR,
> Peter
>
> ----------------------------------------
> From: "chipaudette" <chipaudette@...>
> Sent: Monday, July 8, 2013 1:26 AM
> To: PolySix@yahoogroups.com
> Subject: [PolySix] Temperature of YOUR Polysix?
>
>
>
> Hi All,
>
> As you may remember, I've been doing a lot of mods to my Polysix. After focusing on having fun playing the thing for the last month or two, I'm noticing that the Polysix seems to get quite hot on the back panel. Because I've added two new microcontrollers (plus associated components) and powering them all off the Polysix's built-in power supply I'm worried that maybe the extra heat is my fault.
>
> I've done measurements of my modded Polysix. The thermal bus bar on the Polysix power supply is running about 140F (60C). You can see details here:
>
> http://synthhacker.blogspot.com/2013/07/polysix-temperature.html
>
> In searching the archives here, I found that others have mentioned that the Polysix gets hot (http://launch.groups.yahoo.com/group/PolySix/message/942) but nobody reported any measurements.
>
> Can anyone measure the temperature of their Polysix and tell me how hot she gets? If mine is hot, but normal, I may proceed with even more power-drawing modifications. If mine is hot and abnormal, I won't.
>
> Thanks for any help you can give...
>
> Chip
>
>
>
>
> [Non-text portions of this message have been removed]
>

--- In PolySix@yahoogroups.com, "feline1973" <feline1@...> wrote:
>
> Bloody hell, though:
> just read this in Kiwisix's documentation for the PSU board upgrade:
>
> "Warning: the metal plate between the Power supply
> board and the rear of the Polysix has heat transfer paste
> on it. This paste is also on the rear of the top metal rail
> of the power supply board. Some early heat transfer
> pastes were fairly toxic and can contain Beryllium so
> either wash with IPA or wear gloves and clean up
> carefully after you are finished."
>
> ...beryllium is HELLISHLY toxic, not "fairly toxic" - I would not mess with this at home without some kind of fume extraction system in place: even microgram amounts of beryllium dust inhaled into the lungs can have dire health consequences.
>
> David
>
> --- In PolySix@yahoogroups.com, "peterm" <peterm@> wrote:
> >
> > Hi,
> >
> > I have no idea about the temperature, but I recall reading about a PSU replacement for the Kiwisix kit.
> > http://kiwitechnics.com/kiwisix.htm
> >
> > "A number of Polysix's that arrive at our workshop have had extensive damage across multiple boards. It is our conclusion that this has been caused by overvoltage being applied to all the boards. This can only have come from the Power regulating board and because of this we no longer trust the original power regulating circuitry in the Polysix."
> >
> > It wouldn't surprise me if the original Polysix PSU has little or no margin for additional load.
> >
> > BR,
> > Peter
> >
> > ----------------------------------------
> > From: "chipaudette" <chipaudette@>
> > Sent: Monday, July 8, 2013 1:26 AM
> > To: PolySix@yahoogroups.com
> > Subject: [PolySix] Temperature of YOUR Polysix?
> >
> >
> >
> > Hi All,
> >
> > As you may remember, I've been doing a lot of mods to my Polysix. After focusing on having fun playing the thing for the last month or two, I'm noticing that the Polysix seems to get quite hot on the back panel. Because I've added two new microcontrollers (plus associated components) and powering them all off the Polysix's built-in power supply I'm worried that maybe the extra heat is my fault.
> >
> > I've done measurements of my modded Polysix. The thermal bus bar on the Polysix power supply is running about 140F (60C). You can see details here:
> >
> > http://synthhacker.blogspot.com/2013/07/polysix-temperature.html
> >
> > In searching the archives here, I found that others have mentioned that the Polysix gets hot (http://launch.groups.yahoo.com/group/PolySix/message/942) but nobody reported any measurements.
> >
> > Can anyone measure the temperature of their Polysix and tell me how hot she gets? If mine is hot, but normal, I may proceed with even more power-drawing modifications. If mine is hot and abnormal, I won't.
> >
> > Thanks for any help you can give...
> >
> > Chip
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>

--- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@...> wrote:
>
> Hi All,
>
> As you may remember, I've been doing a lot of mods to my Polysix. After focusing on having fun playing the thing for the last month or two, I'm noticing that the Polysix seems to get quite hot on the back panel. Because I've added two new microcontrollers (plus associated components) and powering them all off the Polysix's built-in power supply I'm worried that maybe the extra heat is my fault.
>
> I've done measurements of my modded Polysix. The thermal bus bar on the Polysix power supply is running about 140F (60C). You can see details here:
>
> http://synthhacker.blogspot.com/2013/07/polysix-temperature.html
>
> In searching the archives here, I found that others have mentioned that the Polysix gets hot (http://launch.groups.yahoo.com/group/PolySix/message/942) but nobody reported any measurements.
>
> Can anyone measure the temperature of their Polysix and tell me how hot she gets? If mine is hot, but normal, I may proceed with even more power-drawing modifications. If mine is hot and abnormal, I won't.
>
> Thanks for any help you can give...
>
> Chip
>

--- In PolySix@yahoogroups.com, "feline1973" <feline1@...> wrote:
>
> Bloody hell, though:
> just read this in Kiwisix's documentation for the PSU board upgrade:
>
> "Warning: the metal plate between the Power supply
> board and the rear of the Polysix has heat transfer paste
> on it. This paste is also on the rear of the top metal rail
> of the power supply board. Some early heat transfer
> pastes were fairly toxic and can contain Beryllium so
> either wash with IPA or wear gloves and clean up
> carefully after you are finished."
>
> ...beryllium is HELLISHLY toxic, not "fairly toxic" - I would not mess with this at home without some kind of fume extraction system in place: even microgram amounts of beryllium dust inhaled into the lungs can have dire health consequences.
>
> David
>
> --- In PolySix@yahoogroups.com, "peterm" <peterm@> wrote:
> >
> > Hi,
> >
> > I have no idea about the temperature, but I recall reading about a PSU replacement for the Kiwisix kit.
> > http://kiwitechnics.com/kiwisix.htm
> >
> > "A number of Polysix's that arrive at our workshop have had extensive damage across multiple boards. It is our conclusion that this has been caused by overvoltage being applied to all the boards. This can only have come from the Power regulating board and because of this we no longer trust the original power regulating circuitry in the Polysix."
> >
> > It wouldn't surprise me if the original Polysix PSU has little or no margin for additional load.
> >
> > BR,
> > Peter
> >
> > ----------------------------------------
> > From: "chipaudette" <chipaudette@>
> > Sent: Monday, July 8, 2013 1:26 AM
> > To: PolySix@yahoogroups.com
> > Subject: [PolySix] Temperature of YOUR Polysix?
> >
> >
> >
> > Hi All,
> >
> > As you may remember, I've been doing a lot of mods to my Polysix. After focusing on having fun playing the thing for the last month or two, I'm noticing that the Polysix seems to get quite hot on the back panel. Because I've added two new microcontrollers (plus associated components) and powering them all off the Polysix's built-in power supply I'm worried that maybe the extra heat is my fault.
> >
> > I've done measurements of my modded Polysix. The thermal bus bar on the Polysix power supply is running about 140F (60C). You can see details here:
> >
> > http://synthhacker.blogspot.com/2013/07/polysix-temperature.html
> >
> > In searching the archives here, I found that others have mentioned that the Polysix gets hot (http://launch.groups.yahoo.com/group/PolySix/message/942) but nobody reported any measurements.
> >
> > Can anyone measure the temperature of their Polysix and tell me how hot she gets? If mine is hot, but normal, I may proceed with even more power-drawing modifications. If mine is hot and abnormal, I won't.
> >
> > Thanks for any help you can give...
> >
> > Chip
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>



[Non-text portions of this message have been removed]

--- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@...> wrote:
>
> I noticed that mention of beryllium, too...but I'm not as familiar with its health consequences. I assume that its toxicity is closely related to the form of the beryllium (the specific compound), I looked up "beryllium thermal paste" to see if I could get a clue.
>
> Wiki (http://en.wikipedia.org/wiki/Thermal_grease) talks about the beryllium being in the form of a ceramic (beryllium oxide). Presumably as a powered ceramic used as a filler in the paste.
>
> Looking up beryllium oxide (http://en.wikipedia.org/wiki/Thermal_grease), they talk about it being used in thermal grease. Under the "safety" section they talk about the problems with inhaling the powder. It does sound bad.
>
> I guess that the question is, how much exposure to powder is likely when handling thermal grease? I'm thinking that the exposure to *powder* will be low. Conversely, though, how much exposure/risk are you willing to tolerate given the that the downside is pretty bad?
>
> Thanks for the heads-up regarding the beryllium thermal grease. Does anyone else have experience with these kinds of thermal pastes?
>
> Chip
>

--- In PolySix@yahoogroups.com, Malte Rogacki <gacki@...> wrote:
>
> The stock power supply was able to power the original Korg MIDI retrofit so
> I guess there will be some kind of power reserve.
>

--- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@...> wrote:
>
> Hi All,
>
> As you may remember, I've been doing a lot of mods to my Polysix. After focusing on having fun playing the thing for the last month or two, I'm noticing that the Polysix seems to get quite hot on the back panel. Because I've added two new microcontrollers (plus associated components) and powering them all off the Polysix's built-in power supply I'm worried that maybe the extra heat is my fault.
>
> I've done measurements of my modded Polysix. The thermal bus bar on the Polysix power supply is running about 140F (60C). You can see details here:
>
> http://synthhacker.blogspot.com/2013/07/polysix-temperature.html
>
> In searching the archives here, I found that others have mentioned that the Polysix gets hot (http://launch.groups.yahoo.com/group/PolySix/message/942) but nobody reported any measurements.
>
> Can anyone measure the temperature of their Polysix and tell me how hot she gets? If mine is hot, but normal, I may proceed with even more power-drawing modifications. If mine is hot and abnormal, I won't.
>
> Thanks for any help you can give...
>
> Chip
>

----- Original Message -----
From: Oakley Sound
To: PolySix@yahoogroups.com
Sent: Friday, July 12, 2013 6:37 PM
Subject: [PolySix] Making the P6 brighter



I've been following Chip's progress with interest. And his recent post
on the dynamic noise reduction filter on the effects board spurred me
onto to investigate further. I too have noticed that the P6 is somewhat
duller than other synths and I had always assumed that with the ensemble
mode off the output was as bright as it could be.

Chip's findings that all four ensemble modes pass through the DNR filter
was something I hadn't really thought about before.

http://synthhacker.blogspot.co.uk/2013/02/mystery-circuit-polysix-post-effects.html

In summary: the P6 has a 12dB/octave low pass filter that is set to
around 600Hz (the actual value depends on whether the BBDs are engaged)
when no notes are playing. This filter opens up when it detects audio
from the voice card. As Chip noticed it takes a finite time for the
filter to open and the filter doesn't always open fully in all cases. I
measured the filter took up to 100mS to open fully. That's a significant
loss of high frequency sound at the start of each note.

Yesterday I went a stage further than Chip. Chip's mod basically forces
the filter open. I decided to remove the filter from the circuit
altogether. This has the advantage of no dynamic filtering (which is of
dubious amenity) and reduces the circuit pathway that the audio has to
go through. The LM13600 isn't a hi-fi part and removing it improves the
signal quality.

The mod:

Remove links J28 and J29. Remove R115 and R109 (which disables the
envelope follower). Remove C73 and C61.

Link out, with a piece of solid core wire, the two left hand holes of
J28 and J29. Now connect with a piece of insulated wire the lower of
these now filled solder pads to the lower pad of C73. The filter is now
bypassed.

Link out, with a piece of solid core wire, the two holes of C61. This
capacitor serves no useful job that I can see.

Result: the P6 can be as bright as any synth. Percussive sounds ring out
where they didn't before. String sounds are really very majestic - you
can really pull off sounding like a string machine now. The slight
increase in background hiss is not a problem for me.

Tony

http://takla-makan.bandcamp.com/
http://www.oakleysound.com




[Non-text portions of this message have been removed]

--- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@...> wrote:
>
>
> So, lacking an stock polysix to measure, I disconnected the components that I added and then i re-measured the synth's temperature. Unfortunately, this excludes the heating due to the stock Polysix's 8049 microprocessor because it has been removed from my system. The result, though, is that de-modified Polysix reaches 136 F (58C) and my modified Polysix reaches 148F (63C). You can see graphs and details here:
>
> http://synthhacker.blogspot.com/2013/07/polysix-temperature-without-mods.html
>
> Estimating the power draw from the 8049 and adding it the heating contribution of that power draw, I estimate that a stock Polysix reaches about 140F (60C). Compare this to my modified synth (148F). Is the temperature of my modified synth a problem? Probably not. But, I probably shouldn't go adding more stuff to it. If I do, I ought to consider adding my own power supply.
>
> Chip
>
> --- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@> wrote:
> >
> > Hi All,
> >
> > As you may remember, I've been doing a lot of mods to my Polysix. After focusing on having fun playing the thing for the last month or two, I'm noticing that the Polysix seems to get quite hot on the back panel. Because I've added two new microcontrollers (plus associated components) and powering them all off the Polysix's built-in power supply I'm worried that maybe the extra heat is my fault.
> >
> > I've done measurements of my modded Polysix. The thermal bus bar on the Polysix power supply is running about 140F (60C). You can see details here:
> >
> > http://synthhacker.blogspot.com/2013/07/polysix-temperature.html
> >
> > In searching the archives here, I found that others have mentioned that the Polysix gets hot (http://launch.groups.yahoo.com/group/PolySix/message/942) but nobody reported any measurements.
> >
> > Can anyone measure the temperature of their Polysix and tell me how hot she gets? If mine is hot, but normal, I may proceed with even more power-drawing modifications. If mine is hot and abnormal, I won't.
> >
> > Thanks for any help you can give...
> >
> > Chip
> >
>

--- In PolySix@yahoogroups.com, "syntegrator" <me@...> wrote:
>
>
>
> Hi Chip,
>
> Have you considered the Power Supply replacement from Kiwitechnics? I have one of these installed in an 'almost' stock P6 (with an Old Crow replacement CPU board) and it certainly brings peace of mind versus the cranky old power supply that machine had installed originally.
>
> http://kiwitechnics.com/kiwisix.htm
>
> Scroll down to see a picture of the Kiwi power board - It's a nice piece of engineering... ;-)
>
> Syntegrator
>

--- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@...> wrote:
>
> Yes, I contacted the Kiwitechics guy (Murry) asking if his power supply gave more capacity than the new one (or just more reliability because it's new). He gave a very prompt reply saying that he thought that the polysix had such good heat sinking (ie, the entire metal panel) that he didn't think that I should have a problem drawing more power from the stock power supply.
>
> Given that he basically just talked me out of a sale, his reply seems pretty authentic. I worry though. Perhaps I didn't fully explain how much extra power I was drawing (which I hadn't quantified at that time). So, I dove in and did my temperature measurements and started this recent thread.
>
> For some reason, I thought that Murry stopped in around here from time to time. I expected him to chime in, given his interest and expertise in the Polysix and its power supply. If he hasn't seen the data, maybe I should shoot him another email...maybe he'd be interested and would be willing to his thoughts...
>
> Chip
>

--- In PolySix@yahoogroups.com, Peter Mörck <peterm@...> wrote:
>
> This sounds really interesting and I'm tempted... but...
> I assume there's no chance of hearing a good quality before/after recording with identical patches played identically? :P
> I want to judge the noise level myself before tearing things apart :)
>
> BR,
> Peter
>

> I'm going to try my non-destructive version of Tony's mod later today and compare it to my own mod where I simply force the filter open by jumpering +15V into C14.
>

On 2013-07-13, at 15:54, "chipaudette" <chipaudette@yahoo.com> wrote:

>
> Here's a sound demo of the mod that we've been discussing. It's a very basic demo, but you'll definitely get the idea of how defeating/removing this VCF really opens up the sound...
>
> https://soundcloud.com/synthhacker/korg-polysix-sound-of-removing
>
> Pretty dramaitc, eh? I call this one "The Snappy Mod". And, because it can be done non-destructively, I highly recommend it!
>
> A full post with schematics, pics, and graphs will come later.
>
> Enjoy!
>
> Chip
>
>


[Non-text portions of this message have been removed]

> Here's a sound demo of the mod that we've been discussing. It's a very basic demo, but you'll definitely get the idea of how defeating/removing this VCF really opens up the sound...
>
> https://soundcloud.com/synthhacker/korg-polysix-sound-of-removing
>
> Pretty dramaitc, eh? I call this one "The Snappy Mod". And, because it can be done non-destructively, I highly recommend it!

> A full post with schematics, pics, and graphs will come later.

>
> Enjoy!
>
> Chip

--- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@...> wrote:
>
>
> Here's a sound demo of the mod that we've been discussing. It's a very basic demo, but you'll definitely get the idea of how defeating/removing this VCF really opens up the sound...
>
> https://soundcloud.com/synthhacker/korg-polysix-sound-of-removing
>
> Pretty dramaitc, eh? I call this one "The Snappy Mod". And, because it can be done non-destructively, I highly recommend it!
>
> A full post with schematics, pics, and graphs will come later.
>
> Enjoy!
>
> Chip
>

--- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@...> wrote:
>
>
> Here's a full post showing how the mod can be done. I give schematics and some pics and the basic audio demo that was linked earlier:
>
> http://synthhacker.blogspot.com/2013/07/polysix-bypassing-post-effects-vcf.html
>
> At the end, I also analyze the background noise in each condition. I found that defeating the post-effects VCF by forcing open the filter actually *lowers* the noise from 100-1000Hz compared to the stock synth. But, it also exposes more of the synth's noise above 2 kHz, as expected.
>
> By removing the VCF (by pulling U15 and jumpering to R168), though, you get the lower noise value in the 100-1000Hz range *and* you get only a very slight increased in noise above 2kHz. Win-Win!
>
> Chip
>
> --- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@> wrote:
> >
> >
> > Here's a sound demo of the mod that we've been discussing. It's a very basic demo, but you'll definitely get the idea of how defeating/removing this VCF really opens up the sound...
> >
> > https://soundcloud.com/synthhacker/korg-polysix-sound-of-removing
> >
> > Pretty dramaitc, eh? I call this one "The Snappy Mod". And, because it can be done non-destructively, I highly recommend it!
> >
> > A full post with schematics, pics, and graphs will come later.
> >
> > Enjoy!
> >
> > Chip
> >
>

> it sounds very noticeably more hissy to me the mod, and not so much

> https://soundcloud.com/synthhacker/korg-polysix-sound-of-removing

--- In PolySix@yahoogroups.com, Oakley Sound <oakleylist@...> wrote:
>
> > it sounds very noticeably more hissy to me the mod, and not so much
> "snappy" as just raspy and nasal!
>
> One thing to point out here is that Soundcloud's compression algorithm
> is particularly bad at highlighting things like increased brightness -
> quite often turning them into something nasty. So it's worth downloading
> the file to give it a proper listen to.
>
> > https://soundcloud.com/synthhacker/korg-polysix-sound-of-removing
>
> Having said that the third sample on that wav file sounds pretty awful
> on one particular voice. Perhaps Chip could upload a more traditional
> bass synth sound with a swept envelope.
>
> It's worth noting that all the mod does is remove the dynamic noise
> reduction low pass filter that the whole instrument goes through. If you
> want your sound to be a little darker as before then simply turn down
> the cut-off frequency just a bit. What the mod does is give you that
> choice - you can now have it brighter if you want where previously you
> couldn't. The Polysix's SSM2044 voice filters are now the ones doing the
> filtering and not having to work against the DNR filtering.
>
> The mod does not significantly affect loud patches with a long attack
> since the DNR filter will be fully open 100mS after hitting the first
> note. Although, by bypassing (or removing) the DNR filter you will have
> less overall noise and distortion within the signal.
>
> But what the mod does do is sharpen the sound of fast transient sounds.
> So plucky sounds will have a lot more life to them.
>
> I can't think of any other synth that has a DNR filter applied to its
> main output when the ensemble/chorus unit is not engaged. The Polysix
> already has noise reduction fitted to the ensemble circuitry so it does
> seem somewhat overkill to install yet another filter on the direct output.
>
> One final point is that if one is fitting the mod like Chip has done
> with the +15V being sent to the envelope follower's buffer then this
> could be done with a switch fitted to the rear panel. Then one can
> engage the DNR filter on the fly.
>
> Tony
>
> http://takla-makan.bandcamp.com/
> http://www.oakleysound.com
>

--- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@...> wrote:
>
>
> Here's a sound demo of the mod that we've been discussing. It's a very basic demo, but you'll definitely get the idea of how defeating/removing this VCF really opens up the sound...
>
> https://soundcloud.com/synthhacker/korg-polysix-sound-of-removing
>
> Pretty dramaitc, eh? I call this one "The Snappy Mod". And, because it can be done non-destructively, I highly recommend it!
>
> A full post with schematics, pics, and graphs will come later.
>
> Enjoy!
>
> Chip
>

--- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@...> wrote:
>
>
> Y'all have good ears...in the "VCF Removed" case, you all easily detected the one "fluffy" voice in my Polysix. It definitely made for a bad demo. Here's a second demo...it's not great, but it's a bit better...
>
> https://soundcloud.com/synthhacker/korg-polysix-sound-of-removing
>
> The others of you, with the "nasal" or "raspy" comment also heard some truth. In my opinion, it is indeed a touch to buzzy with the mod. But this means that I can now turn down the filter cutoff knob on my synth. With the stock Polysix, I was always wanting to open up the filter more, but I couldn't because the knob was already maxed out. Now I've got the added flexibility. My preference.
>
> I hope that you enjoy the newer demo. It's hard doing demos! If you free-hand play the "before" case and the "after" case, the two samples end up sounding too different...the listener hears the difference in performance more than the difference in timbre. So, I was forced to use my (hacked) arpeggiator...hence you get the highly repetitive demo. If I ever put a MIDI jack on my synth, I suppose that I could use a sequencer from my PC...but what fun would that be!?!
>
> Chip
>
>
> --- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@> wrote:
> >
> >
> > Here's a sound demo of the mod that we've been discussing. It's a very basic demo, but you'll definitely get the idea of how defeating/removing this VCF really opens up the sound...
> >
> > https://soundcloud.com/synthhacker/korg-polysix-sound-of-removing
> >
> > Pretty dramaitc, eh? I call this one "The Snappy Mod". And, because it can be done non-destructively, I highly recommend it!
> >
> > A full post with schematics, pics, and graphs will come later.
> >
> > Enjoy!
> >
> > Chip
> >
>

> Cut that 1K resistor (the upper one, not the lower one!) and you'll

--- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@...> wrote:
>
>
> Y'all have good ears...in the "VCF Removed" case, you all easily detected the one "fluffy" voice in my Polysix. It definitely made for a bad demo. Here's a second demo...it's not great, but it's a bit better...
>
> https://soundcloud.com/synthhacker/korg-polysix-sound-of-removing
>
> The others of you, with the "nasal" or "raspy" comment also heard some truth. In my opinion, it is indeed a touch to buzzy with the mod. But this means that I can now turn down the filter cutoff knob on my synth. With the stock Polysix, I was always wanting to open up the filter more, but I couldn't because the knob was already maxed out. Now I've got the added flexibility. My preference.
>
> I hope that you enjoy the newer demo. It's hard doing demos! If you free-hand play the "before" case and the "after" case, the two samples end up sounding too different...the listener hears the difference in performance more than the difference in timbre. So, I was forced to use my (hacked) arpeggiator...hence you get the highly repetitive demo. If I ever put a MIDI jack on my synth, I suppose that I could use a sequencer from my PC...but what fun would that be!?!
>
> Chip
>
>
> --- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@> wrote:
> >
> >
> > Here's a sound demo of the mod that we've been discussing. It's a very basic demo, but you'll definitely get the idea of how defeating/removing this VCF really opens up the sound...
> >
> > https://soundcloud.com/synthhacker/korg-polysix-sound-of-removing
> >
> > Pretty dramaitc, eh? I call this one "The Snappy Mod". And, because it can be done non-destructively, I highly recommend it!
> >
> > A full post with schematics, pics, and graphs will come later.
> >
> > Enjoy!
> >
> > Chip
> >
>

--- In PolySix@yahoogroups.com, "chipaudette" wrote:
>
>
> Here's a full post showing how the mod can be done. I give schematics
and some pics and the basic audio demo that was linked earlier:
>
>
http://synthhacker.blogspot.com/2013/07/polysix-bypassing-post-effects-v\
cf.html
>
> At the end, I also analyze the background noise in each condition. I
found that defeating the post-effects VCF by forcing open the filter
actually *lowers* the noise from 100-1000Hz compared to the stock synth.
But, it also exposes more of the synth's noise above 2 kHz, as expected.
>
> By removing the VCF (by pulling U15 and jumpering to R168), though,
you get the lower noise value in the 100-1000Hz range *and* you get only
a very slight increased in noise above 2kHz. Win-Win!
>
> Chip
>
> --- In PolySix@yahoogroups.com, "chipaudette" chipaudette@ wrote:
> >
> >
> > Here's a sound demo of the mod that we've been discussing. It's a
very basic demo, but you'll definitely get the idea of how
defeating/removing this VCF really opens up the sound...
> >
> > https://soundcloud.com/synthhacker/korg-polysix-sound-of-removing
> >
> > Pretty dramaitc, eh? I call this one "The Snappy Mod". And,
because it can be done non-destructively, I highly recommend it!
> >
> > A full post with schematics, pics, and graphs will come later.
> >
> > Enjoy!
> >
> > Chip
> >
>



[Non-text portions of this message have been removed]

On Tue, Aug 13, 2013 at 8:43 PM, chipaudette <chipaudette@yahoo.com> wrote:

> **
>
>
>
> I decided to make my "non-destructive" modification a bit more
>
> permanent. I removed the clip lead and, in its place, I soldered in a
> jumper wire. Now the synth is more robust and will better tolerate the
> rigors of travel. If I wish to un-do the mod, it's still pretty easy to
> reverse.
> (I'm trying the new "Rich Text Format" interface for the Yahoo Groups
> "Post Message" page. Let's see if it makes the link work
> correctly...)http://synthhacker.blogspot.com/2013/08/polysix-permanently\
> -removing-post.html<http://synthhacker.blogspot.com/2013/08/polysix-permanently-removing-post.html>
>
>
> <http://synthhacker.blogspot.com/2013/08/polysix-permanently-removing-po\
> st.html<http://synthhacker.blogspot.com/2013/08/polysix-permanently-removing-post.html>
> >
> I hope that you're all having a good Summer!
> Chip
>
> --- In PolySix@yahoogroups.com, "chipaudette" wrote:
> >
> >
> > Here's a full post showing how the mod can be done. I give schematics
> and some pics and the basic audio demo that was linked earlier:
> >
> >
> http://synthhacker.blogspot.com/2013/07/polysix-bypassing-post-effects-v\
> cf.html<http://synthhacker.blogspot.com/2013/07/polysix-bypassing-post-effects-vcf.html>
>
> >
> > At the end, I also analyze the background noise in each condition. I
> found that defeating the post-effects VCF by forcing open the filter
> actually *lowers* the noise from 100-1000Hz compared to the stock synth.
> But, it also exposes more of the synth's noise above 2 kHz, as expected.
> >
> > By removing the VCF (by pulling U15 and jumpering to R168), though,
> you get the lower noise value in the 100-1000Hz range *and* you get only
> a very slight increased in noise above 2kHz. Win-Win!
> >
> > Chip
> >
> > --- In PolySix@yahoogroups.com, "chipaudette" chipaudette@ wrote:
> > >
> > >
> > > Here's a sound demo of the mod that we've been discussing. It's a
> very basic demo, but you'll definitely get the idea of how
> defeating/removing this VCF really opens up the sound...
> > >
> > > https://soundcloud.com/synthhacker/korg-polysix-sound-of-removing
> > >
> > > Pretty dramaitc, eh? I call this one "The Snappy Mod". And,
> because it can be done non-destructively, I highly recommend it!
> > >
> > > A full post with schematics, pics, and graphs will come later.
> > >
> > > Enjoy!
> > >
> > > Chip
> > >
> >
>
> [Non-text portions of this message have been removed]
>
>
>



--
C'est La Guerre Moving Pictures Inc.
(204) 918 9317


[Non-text portions of this message have been removed]

On Tue, 2013-08-13 at 23:58 -0500, james meagher wrote:
> The link worked for me. And thanks for posting this - I'm very excited
> about this mod. I was about to do it last week, but when I fired up my
> PolySix for the first time in months, I found that it no longer wants to
> produce sound . . . ah, vintage.
>
> But seriously, as soon as I have time to trouble shoot this issue I'll be
> performing this mod.
>
> Cheers,
> James
>
>
> On Tue, Aug 13, 2013 at 8:43 PM, chipaudette <chipaudette@yahoo.com> wrote:
>
> > **
> >
> >
> >
> > I decided to make my "non-destructive" modification a bit more
> >
> > permanent. I removed the clip lead and, in its place, I soldered in a
> > jumper wire. Now the synth is more robust and will better tolerate the
> > rigors of travel. If I wish to un-do the mod, it's still pretty easy to
> > reverse.
> > (I'm trying the new "Rich Text Format" interface for the Yahoo Groups
> > "Post Message" page. Let's see if it makes the link work
> > correctly...)http://synthhacker.blogspot.com/2013/08/polysix-permanently\
> > -removing-post.html<http://synthhacker.blogspot.com/2013/08/polysix-permanently-removing-post.html>
> >
> >
> > <http://synthhacker.blogspot.com/2013/08/polysix-permanently-removing-po\
> > st.html<http://synthhacker.blogspot.com/2013/08/polysix-permanently-removing-post.html>
> > >
> > I hope that you're all having a good Summer!
> > Chip
> >
> > --- In PolySix@yahoogroups.com, "chipaudette" wrote:
> > >
> > >
> > > Here's a full post showing how the mod can be done. I give schematics
> > and some pics and the basic audio demo that was linked earlier:
> > >
> > >
> > http://synthhacker.blogspot.com/2013/07/polysix-bypassing-post-effects-v\
> > cf.html<http://synthhacker.blogspot.com/2013/07/polysix-bypassing-post-effects-vcf.html>
> >
> > >
> > > At the end, I also analyze the background noise in each condition. I
> > found that defeating the post-effects VCF by forcing open the filter
> > actually *lowers* the noise from 100-1000Hz compared to the stock synth.
> > But, it also exposes more of the synth's noise above 2 kHz, as expected.
> > >
> > > By removing the VCF (by pulling U15 and jumpering to R168), though,
> > you get the lower noise value in the 100-1000Hz range *and* you get only
> > a very slight increased in noise above 2kHz. Win-Win!
> > >
> > > Chip
> > >
> > > --- In PolySix@yahoogroups.com, "chipaudette" chipaudette@ wrote:
> > > >
> > > >
> > > > Here's a sound demo of the mod that we've been discussing. It's a
> > very basic demo, but you'll definitely get the idea of how
> > defeating/removing this VCF really opens up the sound...
> > > >
> > > > https://soundcloud.com/synthhacker/korg-polysix-sound-of-removing
> > > >
> > > > Pretty dramaitc, eh? I call this one "The Snappy Mod". And,
> > because it can be done non-destructively, I highly recommend it!
> > > >
> > > > A full post with schematics, pics, and graphs will come later.
> > > >
> > > > Enjoy!
> > > >
> > > > Chip
> > > >
> > >
> >
> > [Non-text portions of this message have been removed]
> >
> >
> >
>
>
>

--- In PolySix@yahoogroups.com, Frank Carvalho <dko4342@...> wrote:
>
> Worked for me too. But I was wondering. If you are jumpering the signal
> directly to output, bypassing the VCF chip, is it at all necessary to
> remove the chip?
>
> /Frank
>

--- In PolySix@yahoogroups.com, Oakley Sound <oakleylist@...> wrote:
>
> I've been following Chip's progress with interest. And his recent post
> on the dynamic noise reduction filter on the effects board spurred me
> onto to investigate further. I too have noticed that the P6 is somewhat
> duller than other synths and I had always assumed that with the ensemble
> mode off the output was as bright as it could be.
>
> Chip's findings that all four ensemble modes pass through the DNR filter
> was something I hadn't really thought about before.
>
> http://synthhacker.blogspot.co.uk/2013/02/mystery-circuit-polysix-post-effects.html
>
> In summary: the P6 has a 12dB/octave low pass filter that is set to
> around 600Hz (the actual value depends on whether the BBDs are engaged)
> when no notes are playing. This filter opens up when it detects audio
> from the voice card. As Chip noticed it takes a finite time for the
> filter to open and the filter doesn't always open fully in all cases. I
> measured the filter took up to 100mS to open fully. That's a significant
> loss of high frequency sound at the start of each note.
>
> Yesterday I went a stage further than Chip. Chip's mod basically forces
> the filter open. I decided to remove the filter from the circuit
> altogether. This has the advantage of no dynamic filtering (which is of
> dubious amenity) and reduces the circuit pathway that the audio has to
> go through. The LM13600 isn't a hi-fi part and removing it improves the
> signal quality.
>
> The mod:
>
> Remove links J28 and J29. Remove R115 and R109 (which disables the
> envelope follower). Remove C73 and C61.
>
> Link out, with a piece of solid core wire, the two left hand holes of
> J28 and J29. Now connect with a piece of insulated wire the lower of
> these now filled solder pads to the lower pad of C73. The filter is now
> bypassed.
>
> Link out, with a piece of solid core wire, the two holes of C61. This
> capacitor serves no useful job that I can see.
>
> Result: the P6 can be as bright as any synth. Percussive sounds ring out
> where they didn't before. String sounds are really very majestic - you
> can really pull off sounding like a string machine now. The slight
> increase in background hiss is not a problem for me.
>
> Tony
>
> http://takla-makan.bandcamp.com/
> http://www.oakleysound.com
>

On Tue, Aug 20, 2013 at 9:53 AM, chipaudette <chipaudette@yahoo.com> wrote:
> I finally followed-up on Tony's suggestion that C61 on KLM-368 appears to have no purpose and that it could be removed.
>
> When I look at C61, I also see no purpose. I see that it could possible attenuate the lowest bass frequencies. I was curious to see the effect of removing this component. Not wanting (yet) to permanently remove C61, I simply bypassed it with a single clippy jumper wire. Easy!
>
> The result appears to be ~6 dB more of the deepest bass frequencies (down in the 33 Hz neighborhood). That's deep.
>
> If you're interested in the mod, you can check out the details at:
>
> http://synthhacker.blogspot.com/2013/08/polysix-deeper-bass-bypass-c61.html
>
> If you've got good headphones or really good speakers, there's also an audio comparison.
>
> My conclusion is that maybe the Polysix doesn't need these super-deep frequencies. It is a fun change, but I'm not sure it's how I want it to sound all the time. I'll have to live with it for a while before I make my decision.
>
> Thoughts?
>
> Chip
>
> --- In PolySix@yahoogroups.com, Oakley Sound <oakleylist@...> wrote:
>>
>> I've been following Chip's progress with interest. And his recent post
>> on the dynamic noise reduction filter on the effects board spurred me
>> onto to investigate further. I too have noticed that the P6 is somewhat
>> duller than other synths and I had always assumed that with the ensemble
>> mode off the output was as bright as it could be.
>>
>> Chip's findings that all four ensemble modes pass through the DNR filter
>> was something I hadn't really thought about before.
>>
>> http://synthhacker.blogspot.co.uk/2013/02/mystery-circuit-polysix-post-effects.html
>>
>> In summary: the P6 has a 12dB/octave low pass filter that is set to
>> around 600Hz (the actual value depends on whether the BBDs are engaged)
>> when no notes are playing. This filter opens up when it detects audio
>> from the voice card. As Chip noticed it takes a finite time for the
>> filter to open and the filter doesn't always open fully in all cases. I
>> measured the filter took up to 100mS to open fully. That's a significant
>> loss of high frequency sound at the start of each note.
>>
>> Yesterday I went a stage further than Chip. Chip's mod basically forces
>> the filter open. I decided to remove the filter from the circuit
>> altogether. This has the advantage of no dynamic filtering (which is of
>> dubious amenity) and reduces the circuit pathway that the audio has to
>> go through. The LM13600 isn't a hi-fi part and removing it improves the
>> signal quality.
>>
>> The mod:
>>
>> Remove links J28 and J29. Remove R115 and R109 (which disables the
>> envelope follower). Remove C73 and C61.
>>
>> Link out, with a piece of solid core wire, the two left hand holes of
>> J28 and J29. Now connect with a piece of insulated wire the lower of
>> these now filled solder pads to the lower pad of C73. The filter is now
>> bypassed.
>>
>> Link out, with a piece of solid core wire, the two holes of C61. This
>> capacitor serves no useful job that I can see.
>>
>> Result: the P6 can be as bright as any synth. Percussive sounds ring out
>> where they didn't before. String sounds are really very majestic - you
>> can really pull off sounding like a string machine now. The slight
>> increase in background hiss is not a problem for me.
>>
>> Tony
>>
>> http://takla-makan.bandcamp.com/
>> http://www.oakleysound.com
>>
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>

--- In PolySix@yahoogroups.com, "Chromatest J. Pantsmaker" <chromatest@...> wrote:
>
> I play a lot of bass-heavy music. It would be super easy to add a
> switch for this mod. I look forward to trying this on my big
> subwoofers!
>
> On Tue, Aug 20, 2013 at 9:53 AM, chipaudette <chipaudette@...> wrote:
> > I finally followed-up on Tony's suggestion that C61 on KLM-368 appears to have no purpose and that it could be removed.
> >
> > When I look at C61, I also see no purpose. I see that it could possible attenuate the lowest bass frequencies. I was curious to see the effect of removing this component. Not wanting (yet) to permanently remove C61, I simply bypassed it with a single clippy jumper wire. Easy!
> >
> > The result appears to be ~6 dB more of the deepest bass frequencies (down in the 33 Hz neighborhood). That's deep.
> >
> > If you're interested in the mod, you can check out the details at:
> >
> > http://synthhacker.blogspot.com/2013/08/polysix-deeper-bass-bypass-c61.html
> >
> > If you've got good headphones or really good speakers, there's also an audio comparison.
> >
> > My conclusion is that maybe the Polysix doesn't need these super-deep frequencies. It is a fun change, but I'm not sure it's how I want it to sound all the time. I'll have to live with it for a while before I make my decision.
> >
> > Thoughts?
> >
> > Chip
> >
> > --- In PolySix@yahoogroups.com, Oakley Sound <oakleylist@> wrote:
> >>
> >> I've been following Chip's progress with interest. And his recent post
> >> on the dynamic noise reduction filter on the effects board spurred me
> >> onto to investigate further. I too have noticed that the P6 is somewhat
> >> duller than other synths and I had always assumed that with the ensemble
> >> mode off the output was as bright as it could be.
> >>
> >> Chip's findings that all four ensemble modes pass through the DNR filter
> >> was something I hadn't really thought about before.
> >>
> >> http://synthhacker.blogspot.co.uk/2013/02/mystery-circuit-polysix-post-effects.html
> >>
> >> In summary: the P6 has a 12dB/octave low pass filter that is set to
> >> around 600Hz (the actual value depends on whether the BBDs are engaged)
> >> when no notes are playing. This filter opens up when it detects audio
> >> from the voice card. As Chip noticed it takes a finite time for the
> >> filter to open and the filter doesn't always open fully in all cases. I
> >> measured the filter took up to 100mS to open fully. That's a significant
> >> loss of high frequency sound at the start of each note.
> >>
> >> Yesterday I went a stage further than Chip. Chip's mod basically forces
> >> the filter open. I decided to remove the filter from the circuit
> >> altogether. This has the advantage of no dynamic filtering (which is of
> >> dubious amenity) and reduces the circuit pathway that the audio has to
> >> go through. The LM13600 isn't a hi-fi part and removing it improves the
> >> signal quality.
> >>
> >> The mod:
> >>
> >> Remove links J28 and J29. Remove R115 and R109 (which disables the
> >> envelope follower). Remove C73 and C61.
> >>
> >> Link out, with a piece of solid core wire, the two left hand holes of
> >> J28 and J29. Now connect with a piece of insulated wire the lower of
> >> these now filled solder pads to the lower pad of C73. The filter is now
> >> bypassed.
> >>
> >> Link out, with a piece of solid core wire, the two holes of C61. This
> >> capacitor serves no useful job that I can see.
> >>
> >> Result: the P6 can be as bright as any synth. Percussive sounds ring out
> >> where they didn't before. String sounds are really very majestic - you
> >> can really pull off sounding like a string machine now. The slight
> >> increase in background hiss is not a problem for me.
> >>
> >> Tony
> >>
> >> http://takla-makan.bandcamp.com/
> >> http://www.oakleysound.com
> >>
> >
> >
> >
> > ------------------------------------
> >
> > Yahoo! Groups Links
> >
> >
> >
>

--- In PolySix@yahoogroups.com, "feline1973" <feline1@...> wrote:
>
> Not wanting to be an old sourpuss,
> but adding 6dB boosts to something at 30Hz is usually a good way to totally ruin a mix :) It is very hard to accurately hear stuff down there - forget trying it on headphones... and forget most speakers... and the modal bass response of most rooms will totally muck up what you're hearing too... move your chair two feet to the left and you'll hear something different.
> I'd guess that all you'd be doing to the Polysix with this mod is making it eat up headroom in a mix or on a PA, to no good musical purpose (and very likely to a lot of musical detriment)
> On the other hand, for those into Extreme Noise Terror and the 'brown sound', it would be fantastic :-D
>
> David
>
>

--- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@...> wrote:
>
> I'm not going to deny that line of thinking in any way at all. It is super deep, which means that it's inaudible without a lot of power and mass to make it happen.
>
> What it is good for is finally being able to (try to) compete with the prog rocker guy with the Taurus I bass pedals the next time that you're playing the Meadowlands or Wembley Stadium. To hang with that kinda beast, you gotta get DEEP ;)
>
> Chip
>
> --- In PolySix@yahoogroups.com, "feline1973" <feline1@> wrote:
> >
> > Not wanting to be an old sourpuss,
> > but adding 6dB boosts to something at 30Hz is usually a good way to totally ruin a mix :) It is very hard to accurately hear stuff down there - forget trying it on headphones... and forget most speakers... and the modal bass response of most rooms will totally muck up what you're hearing too... move your chair two feet to the left and you'll hear something different.
> > I'd guess that all you'd be doing to the Polysix with this mod is making it eat up headroom in a mix or on a PA, to no good musical purpose (and very likely to a lot of musical detriment)
> > On the other hand, for those into Extreme Noise Terror and the 'brown sound', it would be fantastic :-D
> >
> > David
> >
> >
>

--- In PolySix@yahoogroups.com, "feline1973" <feline1@...> wrote:
>
> Well, you say that - but again, in all seriousness, what makes the Taurus sound so "deep" is not that it's billowing out a sine wave at 30Hz: it's more to do with the way the two VCOs roll around each other and their upper harmonics growl and mildly distort between (pulling a figure out of my ass here ;) something like 80 to 250Hz... psychoacoustically it makes for a hugely deep and solid sounding bass, cos your brain generates elephantine phantom fundamentals. Maybe :)
>
> David
>

--- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@...> wrote:
>
>
> Continuing the discussion about the Taurus from the "Deeper Bass" thread...
>
> When the Minitaur came out, Moog talked about its unusual oscillator sync feature whereby the two oscillators are reset right when a note is started. Then, after the start of the note, the oscillators are allowed to drift in the same way that any analog VCO's will drift.
>
> The fact that they are sync'd right at the beginning would mean that phase of the two oscillators is the same at the start of the note, which means that they constructively interfere, which means that you get a super solid start to every note.
>
> I've always liked that idea. I've been figuring out how to try this kind of note-on oscillator reset on my Polysix (especially with the six-note unison). Again, since I'm not a master of how analog oscillators function, I'm having difficulty seeing how to do it. I'm assuming that I'm looking for a cap that I would need to discharge (ie, quickly short) in order to reset the oscillator. The only cap that looks like a reasonable target would be C54 -- the 6200 pF cap in the per-voice section of KLM-366.
>
> If I put a transistor (or other electronic switch) across this cap and sent it a pulse to quickly short the cap (thereby draining it), would it reset the oscillator?
>
> Chip
>

--- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@...> wrote:
>
> I finally followed-up on Tony's suggestion that C61 on KLM-368 appears to have no purpose and that it could be removed.
>
> When I look at C61, I also see no purpose. I see that it could possible attenuate the lowest bass frequencies. I was curious to see the effect of removing this component. Not wanting (yet) to permanently remove C61, I simply bypassed it with a single clippy jumper wire. Easy!
>
> The result appears to be ~6 dB more of the deepest bass frequencies (down in the 33 Hz neighborhood). That's deep.
>
> If you're interested in the mod, you can check out the details at:
>
> http://synthhacker.blogspot.com/2013/08/polysix-deeper-bass-bypass-c61.html
>
> If you've got good headphones or really good speakers, there's also an audio comparison.
>
> My conclusion is that maybe the Polysix doesn't need these super-deep frequencies. It is a fun change, but I'm not sure it's how I want it to sound all the time. I'll have to live with it for a while before I make my decision.
>
> Thoughts?
>
> Chip
>

--- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@...> wrote:
>
> I made a better set of frequency response measurements with the C61 mod. The graph is much clearer in how the deepest bass freqencies are now extended by the removal of C61. If you're interested, you can check it out at:
>
> http://synthhacker.blogspot.com/2013/08/polysix-frequency-response-with-deeper.html
>
> Also, you'll notice that the frequency response graph (with or without C61) shows a boost to the high treble frequencies. I mentioned this phenomenon in an earlier post regarding "Korg's Built-In Treble Boost". This new graph doesn't necessarily imply the cause of the boost, but it does very clearly show that a boost exists.
>
> There will be follow up on the treble boost later.
>
> Chip
>

Hi!

Chip here, the one from the synthhacker blog that you referenced.  To answer your questions:

Re: R166 (the 1K resistor not being present), I just looked in my synth...mine is also missing.  Interesting.

Re: R167 (the 33K resistor maybe not being 33K), mine is colored orange-orange-orange, which is 33K, as specified.  When I measure it in-circuit with my DMM, it is only indicating 4K or so.  Since the color bands clearly indicate 33K, the lower reading must be because the in-circuit measurement includes parallel paths through ground or something.  Your own evaluation of R167 might be seeing the same effect.  What were the color stripes on R167?

Re: R168 (you didn't ask, but it the 22K that the 33K is jumping around), my R168 is red-red-orange, which suggests 22K as indicated on the schematic, but it is only reading ~5K in-circuit.  So, again, in-circuit measurements can be funny.

If you've been checking out my frequency-response mods, don't miss the others that I did after this one:

Bypass the Post-Effect VCF to open up the sound: http://synthhacker.blogspot.com/2013/07/polysix-bypassing-post-effects-vcf.html

Deeper Bass (Based on Tony's Discussion): http://synthhacker.blogspot.com/2013/08/polysix-deeper-bass-bypass-c61.html  and be sure to read it's follow-up posts.

Flatten Treble Response: http://synthhacker.blogspot.com/2013/08/polysix-flatten-treble-response.html

Good luck!

Chip

Hi,

    I am the new owner of a PolySix, bought recently from a major auction site. Think I have dealt with the battery damage, and have ordered new tact switches from Mouser, but the keyboard rubber domes seem to be a problem.   Only about 1/4 of the keys work.   Cleaning the pcb and the rubber domes (lightly) with IPA didn't seem to do much.  The pattern is not regular, and I have checked the resistance at the connector using the diode position of my meter.   The keys that work are low, and the other ones are much higher.   I have read good and bad things about CaiKote, and the other products, such as the stuff for repairing rear window defrosters, or the Circuit Works pen.   I am wondering if anyone has any long-term experience with these solutions.

The problem with all of them seems to be that it's hard to get something to stick to the rubber, and it flakes off eventually.   Is there one of these that will

fix a keyboard long-term?  Thanks.   Looking forward to reading lots of posts here and learning about my PolySix.   Any chance some replacement key contact strips for a newer keyboard could be adapted to the PolySix?

    Bob

 

Hi,

    I am the new owner of a PolySix, bought recently from a major auction site. Think I have dealt with the battery damage, and have ordered new tact switches from Mouser, but the keyboard rubber domes seem to be a problem.   Only about 1/4 of the keys work.   Cleaning the pcb and the rubber domes (lightly) with IPA didn't seem to do much.  The pattern is not regular, and I have checked the resistance at the connector using the diode position of my meter.   The keys that work are low, and the other ones are much higher.   I have read good and bad things about CaiKote, and the other products, such as the stuff for repairing rear window defrosters, or the Circuit Works pen.   I am wondering if anyone has any long-term experience with these solutions.

The problem with all of them seems to be that it's hard to get something to stick to the rubber, and it flakes off eventually.   Is there one of these that will

fix a keyboard long-term?  Thanks.   Looking forward to reading lots of posts here and learning about my PolySix.   Any chance some replacement key contact strips for a newer keyboard could be adapted to the PolySix?

    Bob

-- 
Tubbutec
Tobias Münzer
http://tubbutec.de
mail@tubbutec.de

Personally, I've had good luck using Caikote.  I've used it on two of my synths (my Mono/Poly and my Polysix)...

http://synthhacker.blogspot.com/2012/12/dead-keys-on-old-korg-try-caikote-44.html

Chip