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View Full Version : calling radio heads......


Satis
20th Mar 2000, 13:40
anybody got any info of interchangeability of carbon, dynamic and em mics.
I was asked to look at an old platronics MS50 headset which I think has a dynamic mic. I'm trying to get it working. Guys in Radio shop tried to test it on a rig used for large modern boeing h/sets (em I'm sure). I thought that would pop a dynamic mic but they assured me it wouldn't?? They said the mic is bust......I don't have access to a dynamic mic a/c or test rig at my airport to check it.

Will/should a dynamic mic work in an em setup? Anybody familiar with the model I've been given to look at?

Wide Body
25th Mar 2000, 05:05
Dynamic (Moving coil mics generally work on anything) they don't need a DC bias voltage on the mic line to generate an o/p like the electret, and carbon types. It's just a little coil rattling around near a magnet.
On some of the smaller light a/c intercomms, if you mix different types of mic havoc will prevail. These units generally can't cope with different impeadance loading like the big interphone systems.
A good test for a dynamic mic is a continuity test. Around 150 ohms is good I think ??? However, the biggest problem with headset mics is the copious amount of aircrew dribble that makes them damp and un-intelligable. "The mic that is!"
Hope this helps.