[sdiy] VCO that goes SHARP in highest octaves??

brianw brianw at audiobanshee.com
Wed Jun 15 23:49:04 CEST 2022

Are polyester caps available in SMD?

Sorry for being lazy, but I recall searching for them in the past and finding none. I had to change to through-hole. However, I may have been looking for very specific poly formulations, not the broader category.

I know that C0G/NP0 have very good specifications, but I don't know the details of whether they're poly formulations or some other magical material.


On May 19, 2022, at 12:57 PM, Sarah Thompson via Synth-diy <synth-diy at synth-diy.org> wrote:
> Chip ceramic capacitors can show changes in capacitance with bias voltage. If stable capacitance is necessary, then specifying something fundamentally more stable like a polyester might be sensible, albeit at the cost of board area.
> On Wed, May 11, 2022 at 2:01 PM Richie Burnett <rburnett at richieburnett.co.uk> wrote:
> > One issue when looking at HF oscillations is sometimes the scope probe
> adds enough capacitance or resistance to stop the oscillation...
> Then the "oscillator going SHARP" condition might go away when the probe is 
> connected!?
> Neil Harper, I guess the VCO does eventually go flat again at some point 
> higher than a C8 pitch?  The pitch errors you mentioned in cents aren't 
> huge.  Does it get worse and worse above the C8 or does it get better again?

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