[sdiy] Tantalum alternatives for re-capping?

[Ben Bradley]

This appnote thing is a few years old (it's no longer on the
manufacturer's site) and only discusses the company's SMT tantalum
caps, but it may be instructive as far as which voltage rating you
choose, and why others are saying use a higher voltage rating, if you
choose to replace with new tantalums. From reading it I'd use at least
twice the voltage the cap will see in normal operation, or at least
twice the original capacitor's rated voltage.
https://web.archive.org/web/20151010013327/http://www.kemet.com/Lists/filestore/Derating%20Guidelings%20for%20Tantalum%202011%20(3).pdf

On Fri, 2 Jan 2026 at 21:03, Michael E Caloroso via Synth-diy
<synth-diy at synth-diy.org> wrote:
>
> If the caps are not on the power rails, I don't replace them.
>
> It's the power rails that are a hazard, because the maximum voltage rating of those caps degrades with age, and the first ones to go are those on power rails.
>
> You should be able to source a modern electrolytic substitute, because technology has advanced in that the farad/cubic-cm density has improved.  I have been able to substitute electrolytic with the same lead pitch of the original tantalum.
>
> MC
>
> On Fri, Jan 2, 2026 at 2:46 PM Colin Hinz via Synth-diy <synth-diy at synth-diy.org> wrote:
>>
>> Hello all,
>>
>> Slightly off-topic, but I am re-capping an old (circa 1977) MXR Digital
>> Delay and am wondering about the numerous small tantalum capacitors that
>> are in this unit. Should I leave them be? Replace them with new solid
>> tantalum parts? Replace them with some other technology?
>>
>> Unfortunately the replacements need to be through-hole parts, which
>> rules out some of the whizz-bang technologies touted as tantalum
>> replacements, such as niobium oxide.
>>
>> Thoughts?
>>
>> - Colin
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