[sdiy] VCF caps in modern synths

[cheater cheater]

I've seen other articles talking about exactly the same thing. It's a
well known issue with multilayer capacitors. Read the author's bio (at
the end of the article). Do you think this IEEE Fellow's obviously
meticulous research is just some crackpot fantasy?

On Sun, Mar 28, 2021 at 7:32 PM Gordonjcp <gordonjcp at gjcp.net> wrote:
>
> On Sun, Mar 28, 2021 at 03:52:37PM +0200, cheater cheater wrote:
> > > On Mon, Jan 18, 2021 at 11:49 AM ColinMuirDorward <colindorward at gmail.com> wrote:
> > > In my 4pole 3320 BPF, the polypropylenes sound slightly better. The obvious difference is that at lower frequency settings, they go into self-oscillation more readily than the ceramics. To my biased ear, the ceramics make some small distortion perhaps, or for some reason add a slight edge to the sound. I did do a blind test using a 2pole 2164 SVF and the difference there is more noticeable than in any other filter I've tested. Here, the polys are a clear win. I want to use words like "liquid, juicy, lush" for the polys vs "bite, edge, grit" for the ceramics. However those are too strong words to describe a very subtle difference. I am waiting to find the right modern mono synth that I can do a capacitor "upgrade" on and test if it's possible to perceive a change in the sound in a factory-made unit. I have an uno synth on the way (was on sale for $135cad?!), perhaps I'll be lucky enough to find space inside that tiny case for four WIMAs.
> >
> > The sound quality you're talking is "roughness" and is measured in Aspers.
> >
> > Tiny capacitors have a very large voltage gradient across a very short
> > casing. They're probably self-modulating, i.e higher voltage means
> > less capacitance. Essentially self-filter-FM.
> >
> > Look at this article:
> > https://passive-components.eu/dc-and-ac-bias-dependence-of-mlcc-capacitors-including-temperature-dependence/
> >
>
> Lots of pretty graphs, for sure.
>
> Has anyone attempted to reproduce these experiments?
>
> --
> Gordonjcp
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