"mikem" wrote a lot of good stuff about aircraft alternators.
....
Alternator whine heard in aircraft avionics audio has nothing to do
with "filtering" at the alternator. It has everything to do with how
the avionics wiring harnesses were fabricated and installed. If the
avionics wiring is properly done using a "single-point-grounding", and
to a lesser extent, proper shielding, there is no detectable
alternator whine or strobe squeal, filters or not!

But what do you know? You only have a PhD in electrical engineering. g

Thanks for the info.

Jon