[sdiy] VCF caps in modern synths

[cheater cheater]

Good distinction, I totally missed that. Yeah, looks like C0G don't
lose capacitance when changing the bias voltage, at least as professed
by Kemet here:

https://ec.kemet.com/blog/mlcc-dielectric-differences/

Also the page for the AVX C0G says "virtually zero voltage
coefficient", missed that too. Although the actual datasheet doesn't
specify it.

So I guess C0G are safe here.

Are Behringer using C0G in the orange 2600 clone that started this conversation?


On Sun, Mar 28, 2021 at 8:06 PM Justin Herrmann <ebn303afxcut at email.com> wrote:
>
> I think the https://passive-components.eu/dc-and-ac-bias-dependence-of-mlcc-capacitors-including-temperature-dependence/
>
> article is great, and I agree with its findings. It doesn't say anything about C0G though. It's about X5R and X7R.
>
> Justin
> On 3/28/21, 12:50 PM cheater cheater <cheater00social at gmail.com> wrote:
>>
>> Sorry, didn't finish reading - that's actually 5 authors, each of
>> which has commendable industry experience. I don't think there's any
>> reason to doubt their findings.
>>
>> On Sun, Mar 28, 2021 at 7:46 PM cheater cheater
>> <cheater00social at gmail.com> wrote:
>> >
>> > 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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