[sdiy] High-K ceramics and audio

Paul Perry pfperry at melbpc.org.au
Thu Nov 30 06:08:38 CET 2023


Now to design a voltage controlled filter using those high-z ceramics...
I've also heard of one used as a motor engine sound transducer, epoxied to
a screwdriver shaft. A very adaptable component.

paul perry Melbourne Australia.



On Thu, Nov 30, 2023 at 1:21 PM Ben Bradley via Synth-diy <
synth-diy at synth-diy.org> wrote:

> According to this presentation, apparently from 2011, for best
> reliability you should never put more than HALF the rated voltage
> across a tantalum capacitor:
>
> https://web.archive.org/web/20151010013327/http://www.kemet.com/Lists/filestore/Derating%20Guidelings%20for%20Tantalum%202011%20(3).pdf
>
> On Wed, 29 Nov 2023 at 17:59, Mike Bryant <mbryant at futurehorizons.com>
> wrote:
> >
> > Indeed so.  But those data sheets are aimed at applications where the
> whole product will be in landfill within 5 to 10 years.  Audio is rather
> unusual in that we still use stuff from the 70s, possibly even earlier.
> >
> > ________________________________
> > From: brianw <brianw at audiobanshee.com>
> > Sent: 29 November 2023 21:56
> > To: Mike Bryant <mbryant at futurehorizons.com>
> > Cc: Andrey Salomatin <filipovskii.off at gmail.com>; synth-diy mailing
> list <synth-diy at synth-diy.org>
> > Subject: Re: [sdiy] High-K ceramics and audio
> >
> > If you pay close attention to data sheets and design guidelines from
> chip makers, even modern ones, you'll find that tantalum are often the
> first type of capacitor that is recommended. Granted, my recollection is
> that this was generally for power supply circuits - I don't recall seeing
> tantalum recommended for audio circuits (but that doesn't mean it's a rule).
> >
> > Brian
> >
> >
> > On Nov 29, 2023, at 1:35 PM, Mike Bryant <mbryant at futurehorizons.com>
> wrote:
> > > In the 70s there were two sorts of tantalums.  One sort was highly
> reliable and recommended for design by companies such as HP, and on the
> Voyager spacecraft, that didn't allow electrolytics except where absolutely
> necessary.  And the other sort were cheaper and crap - they suddenly died
> after 10 to 20 years.
> > >
> > > Guess which type all the modern SMD tantalums are ?  Obviously the
> technology has improved, so they don't die after 10 years, but the aging
> process of aluminium electrolytics is now well understood and it's much
> easier to design a product to last a long time.
> > >
> > > Which in other words means you don't have to 'decap' every
> electrolytic in your classic mixer :-)
> > >
> > >
> > > From: Andrey Salomatin <filipovskii.off at gmail.com>
> > > Sent: 29 November 2023 20:07
> > >
> > > Why not?
> > >
> > > On Wed, Nov 29, 2023, 20:56 Mike Bryant <mbryant at futurehorizons.com>
> wrote:
> > >> No :-)
> > >>
> > >>
> > >> From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of
> Andrey Salomatin via Synth-diy <synth-diy at synth-diy.org>
> > >> Sent: 29 November 2023 18:57
> > >>
> > >> Curious, are people using tantalum for those applications at all?
> >
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