2720 VCO tuning

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Billb3
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2720 VCO tuning

Post by Billb3 »

I have 1 2720-2 and 2 -2a vcos. none of them will tune to the same note per volt or tune to a proper scale. any suggestions?
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PAiA-Scott
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Re: 2720 VCO tuning

Post by PAiA-Scott »

Just posted the procedures for setting up these two models of PAiA VCOs over at the 2720/4700 area linked below. Cross your fingers and hope for the best with the 2720-2: It wasn't long before the 2720-2 VCO design was updated to be the 2720-2A with a more accurate zero-intercept implementation.

http://www.paia.com/talk/viewforum.php?f=31
Scott Lee
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Billb3
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Re: 2720 VCO tuning

Post by Billb3 »

I was finally able to get my oscillators in tune (correct scale)
- 2720-2 I changed cap C1 and then added a 343n cap in parallel
- 2720-2A I added the zero mod, changed C1, and changed R5 to 14k
- 2720-2A I added the zero mod, changed C1, removed R5, and replaced
R8 with a 5K multi turn trim pot.

I'll have to see how well this holds up under use

Bill
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Re: 2720 VCO tuning

Post by marcodiego »

Hi! I'm new here. How the heck do I do a new post? I have a vintage PAIA keyboard that I'm trying to find info about.

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Billb3
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Re: 2720 VCO tuning

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