Phil Allison wrote:
"Scott Dorsey"
Phil Allison

** Tantalums are *very* prone to fail dead short if subjected to a
sudden
self discharge or reverse polarity of even a few volts. Accidental
shorts
from pins 2 or 3 to ground will inevitably happen with phantom powered
mic
inputs.

This is the case with dry slug types only, not with the wet slug ones.

** Kindly supply a reference to a supplier of the latter - with pulse
current specs.

Kemet makes 'em. Look for the mil-spec types. Because of the high cost, you
don't see them very often except in avionics and military gear any longer.
You do see them in a lot of 1970s audio gear, since dry slug types were very
unreliable back then (and because capacitively-coupled audio stages with low-Z
inputs were almost universal then too.)

And it is also the case for some of the newer solid electrolyte aluminum
types,
like the Sanyos.

** Aluminium is not tantalum.

BTW The price for a 47 uF, 25 volt Sanyo SC ( ie solid aluminium) is
ridiculous.

Maybe. The question is how long it lasts. On typical pro audio gear, you may
see a piece of equipment recapped three or four times over a 30-year lifespan.
The cost of the labour far exceeds the cost of the parts.

Right now, I don't think anybody has a grip on real longevity for the solid
aluminum stuff (which is in fact much closer to a dry slug tantalum in
technology than it is to a conventional electrolytic). It is going to be very
interesting to see.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."