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Poly/EX-800 Delay Time Mod - Success!

Poly/EX-800 Delay Time Mod - Success!

2017-06-05 by ashdot@...

Hi,

I think I found the way to control the delay time of the EX800 chorus.

I removed resistors R67 & R68 and replaced them with a potentiometer wired as a voltage divider between D+ and D-.

My scope shows that the pot changes the frequency of the voltage going into the MN3012 clock.

I placed a 10K resistor between D+ and the pot, as any resistance below about 10K stalls the chorus.

Izhar

Re: Poly/EX-800 Delay Time Mod - Success!

2017-06-05 by jusuf@...

Hi
Hi, yes, you need to cut off input from LFO to lead 7 of MN3102. Then you can control "delay" time with knob between leads 6>7 + capacitor between 5>7. You can see it on my old drawing under group files "Cross Modulation mod" .  
By the name "cross modulation"  i was not meaning classic cross-osc, but something as semi-modular use of available signals (chorus LFO...)
It is a pitty I have no records from my >time ago-ed< experiments - just one record of  chorus feedback ...  :
https://groups.yahoo.com/neo/groups/korgpolyex/files/4)%20Modifications/Chorus%20Feedback%20mod/

https://xa.yimg.com/df/korgpolyex/Poly800+-+Matrix.jpg?token=iqmfh2coqUuJ9e8iR0sVDdZMG08gEr4ne1aZ5d3vfxnu4g7hhgAvx4dYflbZCk0iRKL-OpPsmnVxA2HFpZvaoWR_6q_559U1Gs9T88e4s4KA9KgbmkxuPc0KTJOKZev-QRNayyWQQZcY65oRjs2v9Wrwzn_tJjZWNxWamCvtWYwzwqU6Ml5EUqlnSIoD-f17lVwlr-Nr&type=download
https://xa.yimg.com/df/korgpolyex/Poly800+-+Matrix.jpg?t...
View on xa.yimg.com
Preview by Yahoo

 



---In korgpolyex@yahoogroups.com, <ashdot@...> wrote :

Hi,

I think I found the way to control the delay time of the EX800 chorus.

I removed resistors R67 & R68 and replaced them with a potentiometer wired as a voltage divider between D+ and D-.

My scope shows that the pot changes the frequency of the voltage going into the MN3012 clock.

I placed a 10K resistor between D+ and the pot, as any resistance below about 10K stalls the chorus.

Izhar

 

Re: Poly/EX-800 Delay Time Mod - Success!

2017-06-06 by ashdot@...

Thank you!
Your suggestion to cut off the LFO from pin 7 would make it a "straight" delay. 
My goal was to change the MN3102 clock while keeping the LFO oscillation, which I managed by replacing R67 & R68 with a pot and a 10K resistor.
Izhar

Re: [korgpolyex] Poly/EX-800 Delay Time Mod - Success!

2017-06-06 by paulmorison

Well done. Very useful mod! Approx how much does it vary it-what is freq range from one end of the pot to the other Please?

Rgds

P



Sent from my Samsung Galaxy smartphone.

-------- Original message --------
From: "ashdot@... [korgpolyex]" <korgpolyex@yahoogroups.com>
Date: 05/06/2017 20:44 (GMT+00:00)
To: korgpolyex@yahoogroups.com
Subject: [korgpolyex] Poly/EX-800 Delay Time Mod - Success!

 

Hi,

I think I found the way to control the delay time of the EX800 chorus.

I removed resistors R67 & R68 and replaced them with a potentiometer wired as a voltage divider between D+ and D-.

My scope shows that the pot changes the frequency of the voltage going into the MN3012 clock.

I placed a 10K resistor between D+ and the pot, as any resistance below about 10K stalls the chorus.

Izhar

Re: [korgpolyex] Re: Poly/EX-800 Delay Time Mod - Success!

2017-06-07 by Michael Hawkins

I think it's time to add LFO modulation of the Chorus as a real mod in the HAWK.

It would be pretty simple to do.

/Mike


From: "jusuf@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: korgpolyex@yahoogroups.com
Sent: Monday, June 5, 2017 6:31 PM
Subject: [korgpolyex] Re: Poly/EX-800 Delay Time Mod - Success!

 
Hi
Hi, yes, you need to cut off input from LFO to lead 7 of MN3102. Then you can control "delay" time with knob between leads 6>7 + capacitor between 5>7. You can see it on my old drawing under group files "Cross Modulation mod" .  
By the name "cross modulation"  i was not meaning classic cross-osc, but something as semi-modular use of available signals (chorus LFO...)
It is a pitty I have no records from my >time ago-ed< experiments - just one record of  chorus feedback ...  :
https://groups.yahoo.com/neo/groups/korgpolyex/files/4)%20Modifications/Chorus%20Feedback%20mod/

https://xa.yimg.com/df/korgpolyex/Poly800+-+Matrix.jpg?token=iqmfh2coqUuJ9e8iR0sVDdZMG08gEr4ne1aZ5d3vfxnu4g7hhgAvx4dYflbZCk0iRKL-OpPsmnVxA2HFpZvaoWR_6q_559U1Gs9T88e4s4KA9KgbmkxuPc0KTJOKZev-QRNayyWQQZcY65oRjs2v9Wrwzn_tJjZWNxWamCvtWYwzwqU6Ml5EUqlnSIoD-f17lVwlr-Nr&type=download
https://xa.yimg.com/df/korgpolyex/Poly800+-+Matrix.jpg?t...
View on xa.yimg.com
Preview by Yahoo
 


---In korgpolyex@yahoogroups.com, <ashdot@...> wrote :

Hi,
I think I found the way to control the delay time of the EX800 chorus.
I removed resistors R67 & R68 and replaced them with a potentiometer wired as a voltage divider between D+ and D-.
My scope shows that the pot changes the frequency of the voltage going into the MN3012 clock.
I placed a 10K resistor between D+ and the pot, as any resistance below about 10K stalls the chorus.
Izhar