polysix tuning issues

[dr funk]

no--it doesn't have the KLM-396. so obviously it's one of the "new production" keyboards...
so i suppose step 4 is just omitted in this case?
anyway, thanks so much for all the input/feedback...
nate

Mine is a newer one too, without the KLM396. I didn't follow that part of the calibration precisely though, as I was measuring with a frequency counter rather than a tuner. I also used A rather than C as a tuning reference because it was easier that way with the counter (A440, 880, 1600 etc). Sorry I can't be more help either, but the method I used worked out ok for me, even if it was somewhat improvised...

Cheers
Frank

[mantrak]

Hello Polysix tuning society! I recently bought mine (OLD version with KLM396A) and it came detuned. Difference between voices on a same note was almost a semitone, octaves were compressed over the 5 octaves by a couple of semitones. So I Googled and studied... like this:
http://www.oldcrows.net/~oldcrow/synth/ ... iserv.html

and this:
https://groups.yahoo.com/neo/groups/Pol ... opics/1604

and this:
http://www.vintagesynth.com/forum/viewt ... =5&t=33592

I also checked the optocoupler mythology according to this:

http://s188.photobucket.com/user/minebi ... 1.png.html

But apparently you cannot be sure:
http://huebnerie.de/blog/?p=318

Anyway, I assumed the optocoupler is ok and plunged into tuning. The results are not good. There is much less difference between voices, that is almost fixed. However, the octave stretching is terrible. Now it is compressed much more.

All in all, I was tweaking these trims:

- On the KLM396A: VR1
- On the KLM366: VR1 and VR3
- On the KLM366, for each voice: VR10 and VR11

That is all I touched. Missed anything?

It was not clear to me why should I move SW1 to "stretch" position because there is nothing to do except to "confirm" something (according to the manual, step 10). The catch must be somewhere there, as what does it mean to "confirm"? To adjust perhaps? With what? By tweaking which pot?

For me it is also confusing that there are two VR1's in play, both are described as "TUNE MID" here:

http://www.sequencer.de/synthesizer/vie ... hp?t=82149

So there are 2 global TUNE MID controls, one TUNE LOW, and no global TUNE HIGH. Confusing.

Anyway, the question is simple: how do I stretch the octaves globally before I go to individual voices? Can anyone write a good instruction? Or give me a hint and if I ever succeed, I promise to write a really good one.

[mantrak]

Hi, six weeks later and no end in sight. However, I have learned a thing or two which may help or at least provide some comfort to others with similar problems:

1) There is LOT of unreliable information online. Do not expect wrong info to be refuted. Trust the info that is repeated by several sources.

2) Have someone qualified and experienced to check the circuitry as soon as you have trouble tuning. If you cannot get it right in say, an hour, there must be something wrong (possibly optocoupler, but not necessarily).

3) You will not have much problems getting all six voices staying together. The problem is the stretch, how many tones you get per octave. That is applied equally to all six voices. Faulty "antilog" circuit will result in having 8 to 15 tones per octave, depending on the octave number (lower octaves are stretched, higher are squeezed). Once tuned together, all six voices will be off by the same amount.

4) Have some microtonal fun, enjoy the weird tuning while you can I am considering a mod which would give me control over the octave stretch.

Will keep you posted!

[db0451]

1) There is LOT of unreliable information online. Do not expect wrong info to be refuted. Trust the info that is repeated by several sources.

Amen. As long as those several sources aren’t people on the internet saying ‘I heard X is true’. People will repeat anything. As you’ve found out, the ones to believe are the ones who have measurements, pictures, and rationales! (and adequate literacy is often a good hint too)

The repair sounds kinda wild. Interesting, though. If the price hadn’t already put me off the P6, things like this would! The infamous Roland 80017 chips have given me plenty ‘analogue organic unpredictability’ for 2014~15. I hope I bet it’ll be totally worth it when you get it sorted, though. Keep us posted! And if that weird tuning inspires any creativity, we need to hear it.

[Sava66]

Sam, I also have a funky sounding polysix. It's hard to say exactly what's wrong. It just doesn't play patches like it "should." I.e. Programming the factory patches does not result in patches that sound right (brass, strings, etc) when you fixed yours, did you just go through the calibration procedures from start to finish? Did you have an o-scope? Sometimes I feel ready to do this and then I get to the first line and it says "put a dummy connector" sand I get scared. Could you detail a little better the troubleshooting process you went through? I don't have access to a synth tech right now.

[sam]

I always follow the service manual for tuning..after over 50 polysix repairs I have got the hang of tuning these things.

Is it the tuning that's off...?