[sdiy] High-K ceramics and audio

[brianw]

I'd also like to point out that the data sheets I'm referring to are not aimed at design of disposable consumer products. Instead, they're aimed at high-precision scientific instruments. The only electronics that last as long as 70s "hi-fi" gear are scientific instruments.

Brian


On Nov 29, 2023, at 9:22 PM, Ian Fritz via Synth-diy <synth-diy at synth-diy.org> wrote:
> I have always used overrated tants, and have never ever had one fail!
> 
> Ian
> 
> On Nov 29, 2023, at 7:19 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
>>> 
>>> 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?