"John Smith" wrote in message
...
In article NBmsk.718$lf2.305@trnddc07, "Mike"
wrote:

wrote in message
...
On Aug 23, 12:46 pm, noname wrote:
The microphone in my old headset went TU and need a replacement.
Anybody have a working one they would like to part with?

Thanks

Dave

You could probably fix it with the electret mike from a
cheap telephone (not an old carbon-mike phone). I built a headset once
and used the mike from a $3 corded phone, no preamp or anything, and
it worked OK. Had to put a small capacitor across it to bleed off some
of the high freqencies. The mike itself was maybe 3/8" diameter, about
the same thick, and fit nicely into a holder carved of wood.

Dan

That sounds like a lot of work to develop something that's going to be
less
effective than a replacement, but I can't say I'm innocent of spending
way
too many man-hours trying to save a few bucks. The problem with using
one
from a telephone is I don't think the impedence matches up and most
aviation
mics have some type of noise cancelling circuitry.

What makes you think the impedence of the ones in the telephones are
different from the ones in your headset?

Because they are two different devices used in two different applications.
All microphones, even electret models, don't have the same impedence and
there are wide variances depending on the application. Even a mic removed
from a DC military headset won't work well in their civilian version because
of the differences in impedence.

What makes you think they are the same?