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

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Subject: Re: [PolySix] Re: PolySix only works in test mode?

From: <backshall1@bellsouth.net>
Date: 2019-04-24

A couple more things. You don’t need an oscilloscope for the D/A adjustment. It’s just a lot of finicky turns of VR6 and VR7 and watching the Program LEDs. For the MG and PWM, you can probably just set their ranges to your own personal preferences without an oscilloscope. If it sounds good to you and you are the only one playing it, why not? For PW VR3 adjustment, the objective is to get the pulse width down to zero when the knob is at 10. As you turn up the PW knob, the pulse will get thinner and thinner until the note you are playing is no longer audible. This is used in some patches to “turn off” the oscillators so only the filter resonance and sub-oscillator can be heard.
Don B.
 
Sent: Wednesday, April 24, 2019 8:09 AM
Subject: Re: [PolySix] Re: PolySix only works in test mode?
 
 

 
The D/A Adjustment is the most critical to getting all knob ranges correct. If the thing boots up properly every time, then the Reset circuit adjustment is probably okay. The filter tracking is all done on the KLM-366 and you need to get the KLM-367 calibrated first.
They only list 4 items for KLM-367 check and adjustment:
(1) Reset circuit
(2) D/A adjustment
(3) MG adjustment
(4) PW/PWM check and adjustment
 
I should mention two important things. Correct +/-5V and +/-15V supplies need to be set first. If you tweak these later, you may have to recalibrate everything else. That picture of the “Normal setting” is important. Make sure all knobs and switches are set just like the picture before attempting the D/A adjustment or anywhere else in the service manual where they tell you to start with the normal setting.
 
Don B.
 
Sent: Wednesday, April 24, 2019 1:09 AM
Subject: Re: [PolySix] Re: PolySix only works in test mode?
 
 

Thank you! Yes, i'm really glad that it's working this well right off the bat. I don't own an oscilloscope so it might be a while until I can calibrate it if I do it on my own. How crucial is it to calibrate the polysix?

The only things i've noticed are the attack, decay, and release knobs only really responding in the VCA when turned about halfway up, which could be normal behavior for all I know. There's still a good range from 5-10, and the filter still seems responsive at levels below 5. The only other issue besides that is that the resonances on the filters aren't perfectly tuned when using key tracking. Nothing too major.