1V/oct scale circuit

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pix
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1V/oct scale circuit

Post by pix » Thu Feb 18, 2021 6:36 pm

I just got a cv.ocd converter and I'm noticing that the scaling of my synth is a bit off. It's tuned to its internal keyboard and it becomes progressively flat when you go up the octaves using external voltage. The output of the converter is spot-on so this is probably due to a different voltage coming from the internal kbd.

I could re-tune it based on the ext voltage but would prefer to tweak the V input. The cv.ocd doesn't have a "scale" adjustment like the kentons, but it does have a 1.2V/oct mode. So I'm wondering if it's possible to make a V divider with a trimpot and get the right scale from it (I'm assuming it should be around 1.01V/oct or something...

If this is possible is it just a matter of putting a trimpot-to-ground? or do I need to do anything else to keep it linear across octaves?

Thanks!

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MikeDB
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Re: 1V/oct scale circuit

Post by MikeDB » Fri Feb 19, 2021 12:25 am

You can try the trimpot first. I don't know what the output impedance of the external source is so can't advise a value.

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pix
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Re: 1V/oct scale circuit

Post by pix » Fri Feb 19, 2021 11:04 am

OK, I went with 1k/5k and seems to be working. Thanks!

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