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 9710 VCA inverted CV output 
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Joined: Sat Jul 30, 2011 5:46 am
Posts: 70
Post 9710 VCA inverted CV output
Just thinking out loud here..is there any way to access the inverted CV signal that is normaled from the Left CV input to the Right CV input. Is there a way to tap this inverted signal and bring out to a TS jack maybe?

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James


Fri Mar 20, 2020 7:04 am
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Joined: Thu Sep 24, 2009 2:14 pm
Posts: 95
Post Re: 9710 VCA inverted CV output
it's been quite a while since i looked at the 9710 schematic.

i'm thinking that any voltage brought out to the front panel would require a noninverting buffer (NIB). (Input on +, - tied to output)

Let me study sch more. I'll be back......

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Sat Mar 21, 2020 11:51 am
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Joined: Sat Jul 30, 2011 5:46 am
Posts: 70
Post Re: 9710 VCA inverted CV output
great..thank you toneman. I only know enough to be dangerous with this. I'm learning, but not that confident knowledgeable or confident yet.
Maybe the output on pin1 of IC3:A?

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James


Sun Mar 22, 2020 7:33 am
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Joined: Thu Sep 24, 2009 2:14 pm
Posts: 95
Post Re: 9710 VCA inverted CV output
Yes, that should work.
Input to CVleft goes to inverters IC3d and IC3a. IC3c drives tranny Q2 180deg from Q1.

Yes, the ivoltage at test point “B” should be the inverted voltage you’re looking for! It’s already “normalized” into IC3c thru J5, but I would add a buffer before going to a front panel jack just to reduce loading effects. To work without a buffer, just add a wire from test point “B” to a new panel jack. Then, whatever voltage goes into CVleft will be 180deg out at test point “B”. Example: +5V at TP-E gives -5V at TP-B. Otay?

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Sun Mar 22, 2020 12:51 pm
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Joined: Sat Jul 30, 2011 5:46 am
Posts: 70
Post Re: 9710 VCA inverted CV output
adding a wire to a new external jack seems the easiest and least complicated solution. I should probably ground the new jack with all the others yes?

coolness, instant CV inverter with just a simple mod. The only thing left for this VCA to be able to do would be voltage offset. But I don't see anything that would allow me to do that with this module. Then it would become a Frac version of Maths..:)

Thanks so much toneman..you've been a huge help and I've learned more about electronic circuits from you just by these 2 mods.

I'm sure I'll have more ideas about mods soon. I'm trying to stay within the Paia ecosystem as much as possible. I love the loose organic analog sound of Paia..nothing else out there really like it at all. Dirt is good..:)

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James


Sun Mar 22, 2020 4:17 pm
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