tantalum capacitors

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I have this old Tandberg cassette recorder which is full of tantalums. Compared to electrolytics they have smaller series resistance, low inductance and cover the audio spectrum pretty well. I don't think they can be beaten in the lowest frequentie range as a coupling cap. And they are cute.
 
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When tantalums fail, they fail spectacularly!

here is the problem ... devices with 40 years of life and beyond with tantalum capacitors in the circuits can cause unimaginable damage if they jump creating damage in sequence.
Reading an online tip the same Pass suggested replacing them in his old preamplifiers just to be safe but there are many devices that have these capacitors.
Today that everything is miniaturized, tantalum capacitors maybe no longer successful as capacitance vs size, also low ESR and stability over a wide temperature range is not only a feature of the old tantalum, same for vibration immunity . IHMO
 
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Performance in terms of what? I was under the impression their only trump card was the density (capacitance for size).
You say irreplacable where they are placed, so what exactly is this place we're placing them?
Tantalums ten to have a low ESL (Equivalent Series Inductance) compared to aluminum types, that that is their key advantage when used in circuits involving high frequencies.
 
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Here's a previous thread (actually I'm sure there are many, but this has a link I posted):
https://www.diyaudio.com/community/threads/tantalum-capacitors-sound.330072/
In my post, #21, I linked to a remarkable app note from a tantalum manufacturer. The link no longer works but was saved and is available here:
https://web.archive.org/web/2015101...Derating Guidelings for Tantalum 2011 (3).pdf
It give some dire warnings about the failure rate of tantalums, suggesting (to me at least) that anyone interested in reliability should have AT MOST 1/2 the rated voltage across a tantalum capacitor at all times.
Toward the end it discusses polymer tantalums, apparently much improved, but still it suggests derating rated voltage by 10 to 20 percent for improved reliability.
 
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Recent tantalum caps are good and have relatively normal failure* ratings when one takes care to overdimension them with regards to maximum voltage ratings. Solid aluminum capacitors (meant as a better replacement) had very good properties but as usual with very good parts not many wanted to spend more money. Out of production.... Anyway, FWIW I used and still use Kyocera /AVX 35V rated TPS series parts for max. 15V operational voltage and had no (0) failures till now. They were used in numbers and they were connected directly to the power rails.

Niobium polymer caps are also OK and they are available in the same SMD footprints as tantalum caps depending on the value but with lower maximum voltage ratings.

*The memory keeps remembering exploding drop types and older series exploding and sometimes shorting tantalum SMD caps. Those days are over.
 
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Yes I have but …. I did not write any notes and haven’t used them since. You mean PPS?! I have used Panasonic PPS caps in SMD and they were very good then but large for the value, limited in maximum value/voltage and they were fragile as they had an "open" structure. Still have them in stock. My wish was to have them in a dipped version in SMD.

PET is the lowest (no! ->) most standard quality in film caps AFAIK. I use these in abundance (MKT/MKS/Mylar/Polyester) in through hole versions by Wima for decades and they are fine, better than most electrolytic and ceramic caps anyway. Fine as in good sounding, not breaking down and just doing their job so industrial quality.
 
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Yes, Kyocera/AVX or Kemet and bought fresh from normal distributors. Avoid anything unknown/unbranded/chinese or the famous Aliexpress brand in tantalum caps. Please do a search on Aliexpress and see the many unknown types and series. Buying those is gambling but their most excellent electrical property is a high mg/$ rating which is convincing to many.

First we had the Coltan debacle, then the exploding tantalum caps evolving into reliable (but still black swan) high temp tantalum polymer caps and now the Chinese producers. What can go wrong? :)
 
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