Re: [korgpolyex] Re: DCO2 detune PWM?
2011-07-22 by billmeirelles@uol.com.br
Put the output of you Poly 800 into a scope and you will see that your Poly will never output a square wave, looks more like a fuzzy saw wave, anyways, finding
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2011-07-22 by billmeirelles@uol.com.br
Put the output of you Poly 800 into a scope and you will see that your Poly will never output a square wave, looks more like a fuzzy saw wave, anyways, finding
2011-07-22 by billmeirelles@uol.com.br
Audio input is the easiest way to acheive this, you will need a rectified voltage doubler with the positive output connected to the middle terminal of the
2011-07-22 by 7yash
I second the idea, although it can also be done from the external audio in mod.
2011-07-22 by k9k9dog
if this is being discussed, any plans to add pulse width? (to original DCO) eg: if the square is produced by a comparator, varying the input compared to will
2011-07-22 by 7yash
Here is my first test with the FM-800 mod. Needless to say that after the Moog Slayer and 12dB mod, this is supremely interesting as a simple way to extend the
2011-07-22 by Michael Hawkins
Gordon, I want to be able to digitally control the oscillator variation of DCO2. Digital control also might mean using a D2A or use an analog control. Or even
2011-07-21 by 7yash
Thanks for the info, Mike. You sure know your way around it. I totally agree about the Osc section limitations, and this is why any way where we could improve
2011-07-21 by Michael Hawkins
Yes, you could mix them but it wouldn t do anything much at all. Let me explain... The biggest drawback of the Poly-800 design was the tone generator. The
2011-07-21 by 7yash
Hmmm, interesting. Do you think they are mixable with the original DCOx signal without detriment?
2011-07-21 by Michael Hawkins
Those two chips come after the tone generator. They take the square wave outputs of the TG (16,8,4,2) and buffer them and also provide the quasi triangle wave
2011-07-21 by Josh Nursing
They re quite extensive for sure and I wish I could build such upgrades myself. As for me, fixing and enhancing the Poly-800 is a way for me to get into synth
2011-07-20 by billmeirelles@uol.com.br
IC4 and IC5 they come right before the MSM5232 chip and inputs at the MSM5232 are marked as 16 , 8 , 4 and 2 , looks like they are the clock dividers. Em
2011-07-20 by Josh Nursing
They are the IC4 and IC5 chips respectively. ... -- Josh Nursing Skype (preferred): yashnur Google Chat: josh.nursing@gmail.com Cell: +1 (514) 652 9738 ...
2011-07-20 by Michael Hawkins
Keep in mind that the AtomaHawk (which requires the HAWK as well) upgrades automatically control the FM-800 DCO source for you. Along with all of the other
2011-07-20 by Michael Hawkins
I don t think so. The octave selection is done inside the MSM5232 tone generator. Which chip are you talking about? Mike ________________________________ From:
2011-07-20 by billmeirelles@uol.com.br
You could try to put a resistor between the RES pot and the pcb, I decided not use a resistor as the high RES level is great for creating kick sounds. Let me
2011-07-20 by 7yash
Got some new parts and did these three mods tonight before tackling the External Audio In one: http://www.youtube.com/watch?v=32rDZ5IdLew As mentioned, the
2011-07-20 by billmeirelles@uol.com.br
I m not sure, but looks like they are the clock dividers for the octave switches. Em 19/07/2011 21:57, 7yash escreveu: Yes, looks
2011-07-20 by 7yash
Yes, looks more like it. Interesting stuff, what does that Pin 1 do then?
2011-07-19 by billmeirelles@uol.com.br
No, I believe you should connect it to pin 7 of IC5 where it leads to R76. The other side can still be connected to R22, seems to work. Em 18/07/2011 23:12,
2011-07-19 by 7yash
Yes, I was looking at that DCO1 FM-800 mod today in the schematics too. Basically, they re tapping into IC 4 and Pin7, with the nearby R 74. If you trace that
2011-07-19 by billmeirelles@uol.com.br
Yes, Silent Way is great, you get synced LFOs with lots of wave shapes, o Step LFO and lots of other stuff. You made your point about the DCO selector, I
2011-07-19 by 7yash
I will definitely look into Expert Sleepers at one time. I think you mentioned getting extra LFOs and other controls like this, so this will be handy. As for
2011-07-19 by billmeirelles@uol.com.br
Select between DCO1 or DCO2 will give you the same response as both DCOs are exactly the same, no diference between them, as for noise or external audio it can
2011-07-19 by 7yash
Nice. Can t wait to get the proper parts for these mods. On circuitbenders.co.uk, they have a switchable source for the FM modulation: DCO1 or DCO2 or Noise or
2011-07-19 by billmeirelles@uol.com.br
Only if the pot value is too small, than the ground will leak and you will loose signal power, if you are using a 50k or bigger it should be ok, I do prefere B
2011-07-19 by 7yash
Tried the Moog Slayer pot mod with pots I had in hand. If I use a smaller pot resistance value, it s normal that I get a low range, right?
2011-07-18 by billmeirelles@uol.com.br
Ur welcome ;-) Take care, Bill Meirelles Em 18/07/2011 19:35, 7yash escreveu: Thanks for the additional info, Bill. It does makes
2011-07-18 by 7yash
Thanks for the additional info, Bill. It does makes more sense to mix another Noise source prior to using the External Audio In rather than Mix it with the
2011-07-18 by billmeirelles@uol.com.br
The noise level is VR3, you have to swap the wiring from left to right or the pot will reverse the noise level, 0 pos = 100 and 100 pos = 0. I ve never tried
2011-07-18 by 7yash
Thanks Bill, I am ready to try that and also the 12/24 Db Filter mod. Then, I ll also do the Moog Slayer and FM-800 mods. Much Fun. How would one wire the
2011-07-18 by billmeirelles@uol.com.br
Yes, I believe C24 is the one, it s located right after the trasistors of the noise generator but it input at pin 7 not 19, you should desolder the negative
2011-07-18 by Gordon JC Pearce
On Mon, 18 Jul 2011 00:55:06 -0000 ... Not easily, but you could use a crystal oscillator with a varicap diode to pull it a few kHz. I don t know if that
2011-07-18 by ackolonges
Thanks a lot for your reply Don, I ve taken out R1 and D1, and soldered in a battery. Everything works great :) I ve also added the cutoff/res and FM800 knobs
2011-07-18 by 7yash
It looks like C24 is the one: it the one just below the 4 yellow components on the right of the NJM2609 chip.
2011-07-18 by billmeirelles@uol.com.br
Yes, I m sure it is, I bet it is just before pin 19, if you follow the tracks you will find it, connect the tip of your audio signal to the negative leg of the
2011-07-18 by 7yash
Hi Bill, Looks like wiring through a cap is the way to go. I found this existing thread. It is not easy to make full sense of it as it is:
2011-07-18 by Bill Tomlinson
Hi. Anybody know who the manufacture of the 2.0mm wire to board connectors? Battery leakage (the drycells) has eaten several. Looked thru Mouser, but nothing
2011-07-18 by korgpolyex800
I am looking for some help from some of you electronics engineer types that i know are on this forum. I want to create a new detune circuit to include in the
2011-07-17 by billmeirelles@uol.com.br
I m not sure how I did it, I found the descripton at the forum but can t remember where, anyways I believe I took out the negative leg of the cap prior to pin
2011-07-17 by 7yash
Hi all, Considering that the Osc section of the Poly-800 uses an additive form synthesis with Square waves, I thought that the next nice mod for mine would be
2011-07-15 by backshall1 (dsl)
Hi Jason, If those solder pads look clean, with no traces of old solder, then you probably have one of the in between models which had solder pads added to
2011-07-15 by ackolonges
Hi, I got a hold of a poly-800 recently, and it doesn t hold patches so I figured the battery had run out. When I opened it up I found that the place where the
2011-07-11 by billmeirelles@uol.com.br
Yep, check the service manual, there is a VR for tune. Em 11/07/2011 08:30, honod3k escreveu: After being on for over an hour (w/ power
2011-07-11 by Michael Hawkins
The master TG clock is not particularly susceptible to power supply drift but nevertheless, I would check your power supply for drift first. Then, if the power
2011-07-11 by honod3k
After being on for over an hour (w/ power adapter, not batteries) my Poly went so far flat that I had to move the Tune slider all the way to the right. Soon
2011-07-05 by Josh Nursing
Makes sense, but the service manual doesn t contain much concerning adjustment for the Chorus board. I ll check those trim pots again, especially if there s
2011-07-05 by billmeirelles@uol.com.br
There s no adjustment procedure in the service manual? Maybe the effect is to soft for you to hear on the headphones, the chorus may need adjustment, twisting
2011-07-05 by Josh Nursing
In the Mk1, there s only a Chorus board, no delay as in the MkII. The only setting you have per program is turning off or on the Chorus. The effect does seem
2011-07-05 by billmeirelles@uol.com.br
Mine is a Poly 800 II so I don t know exactly how the MkI works, but it seams like a strange behavior, have you tried to change the chorus settings? Usualy