[sdiy] phantom power: how to avoid electrolytics?

[Czech Martin]

Most good microphones require that the audio path carries also
DC power to the microphone (aka phantom power).

Usually this dc voltage is blocked at the amplifier
with electrolytics.
Usually using electrolytics in the audio path is no such
a good idea.

But: the biasing is large, so the the cap faces a large dc
field with a little ac riding on top.
I think even expensive gear has electrolytic caps in there.
So maybe it isn't so harmfull in this application?

Or are there better solutions arround?

As far as I remember, the output impedance of studio
mics is about 100-500 Ohm. The amplifier should be 
in the same area (was this noise impedance matching?
could someone point out for my poor brain what the
optimisation idea was?)

So the caps impedance should be way lower even @ 20Hz.
Assuming 200 Ohm, this gives about <= 160uF or so
as a ball-park figure. Quite a lot for foil cpacitors.
with 2000 Ohm impedance things would be manageable.

Any thoughts?

Martin Czech