[sdiy] Coarse and Fine Pots

[Terry Bowman]

> On May 24, 2025, at 9:34 PM, Michael E Caloroso <mec.forumreader at gmail.com> wrote:
> 
> Just sum the CVs from both pots to the CV summer opamp, configure the fine tune pot to lower gain.

It's the frequency pot for a Schmitt trigger/integrator LFO. I'd love to have some VCLFOs but that isn't in the cards. I'd love to build a modular version of this thing but I don't have the cash.

A dual concentric pot would be convenient and cool but it's not a deal-breaker. I saw a 100kΩ / 20kΩ somewhere but it was out of stock, probably for a long time.


> On May 24, 2025, at 11:29 PM, Ben Bradley via Synth-diy <synth-diy at synth-diy.org> wrote:
> 
> It's been quite a while since I've touched an SEM, but yeah, I think
> those are two separate knobs on a reduction system that goes to the
> shaft of one pot. These were used on the tuning shafts of old radios
> from many decades ago. It's usually a ball bearing reduction and they
> appear to be rather expensive.

I had a Two-Voice and I loved it. No stops on the fine pot, what a concept.

I hadn't found any for sale up until now so thanks for that. Are the knobs twice as much?


Terry Bowman, KA4HJH
"The Mac Doctor"

https://www.astarcloseup.com

“...the book said something astonishing, a very big thought. The stars, it said, were suns but very far away. The Sun was a star but close up.”—Carl Sagan, "The Backbone Of Night", Cosmos, 1980


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