[sdiy] Approximate linear 2164 scheme using zeners

[Sean Ellis]

Based on a suggestion on Modwiggler I tried a cheap way to get rough linear response from a 2164 using diodes to compress the CV, then scale it. So far it looks good in Spice but comes (I think) at the cost of S/N. Haven't tested this yet but if it works, I'm sure it could be improved.

(I'll try to attach the pics here but if not check the link.)
https://modwiggler.com/forum/viewtopic.php?p=3719506#p3719506

Ignore high resistor values in the signal path, had some trouble figuring out the 2164 model. The circuit is a polarizing VCA using an inverted part cancelling. With the exponential response this crossover is not really useable even from a large panel pot, it's so sharp. Dont need any precision here but a softer front panel experience (I just want to save a chip 😉 )

When I took these captures I had made the expo section lopsided in error, but the shape is the same when spaced out more. Any thoughts? I think it could be trimmed better down to 0 volts but that was where I started to lose the shape, rather trade some attenuation for the shape.


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