Racal-Amplivox magnetic microphone insert

[Sparks]

The one on the left has a NC electromagnetic microphone, probably much the same design as the one we've been discussing. The one on the right has a regular moving coil dynamic type, same design as the giveaway types with old cassette recorders but higher quality and NC.

[ScottBouch]

Ah, now I found it, how these mics were available for Amplivox headsets, see attached. I read in an earlier post about the Airmed/CCI Airlite 62, which led me up the garden path - bit of confusion!

I have an Amplivox Astrolite in the garage too, I'll go and dig it out.

[ScottBouch]

Ok, so here is my Amplivox Astrolite, with yet another different mic type!

Don't know why this has a DIN plug, and no mic switch in the cable, not sure of its intended purpose.

Also not yet stripped apart the earpiece to look for an amplifier like yours.

[Sparks]

The microphone in your Astrolite is a standard, i.e. not NC, moving coil dynamic type. Impedance 500 ohms. The DIN plug suggests this headset was intended for a language lab. Our Tandberg language lab at my high school (nearly 40 years ago) used Astrolites but with the Nexus US spec NATO plug.

[ScottBouch]

Originally Posted by Radio Wrangler

Glider pilots have very quiet cockpits and like to flaunt it. They like to use a cabin speaker rather than headphones, and they like to use a straight-forward dynamic mike on a flexible gooseneck.

Had my first glider flight last year, as you say, no headsets and a gooseneck mic fitted. All of our conversation was literally just spoken in the cockpit, instructor sat behind me.

He only used the radio once to land too.

[ScottBouch]

Another mic, modern RACAL Atlantic headset, with another type of noise cancelling mic. I also have this type of mic element on booms for Mk4 flying helmetsfrom the 90's

[ScottBouch]

And the Ampluvox /RACAL Jetguard, with yet anothrr noise cancelling mic. This type of mic also appears on flying helmets.

[Sparks]

The microphone on the Atlantic headset is a moving coil NC type, 200 ohms. Also available in grey! I've no idea about the other one.

[ScottBouch]

These all should be 200 Ohm dynamic for compatibility to aircraft with NATO sockets.

Having used noise cancelling mics in an EE Lightning on engine testing, they still pick up a lot of noise. Much better to use an oxygen mask or throat mic.

[delaitt]

Hello Scott

Is there a schematic for the Airmed amplifier adapter that you mentioned on earlier post in this thread?

I am interested about it for connecting an airlite 62 to a Collins 618T

By default the Collins 618T uses a carbon Microphone with an 18V DC on the line

I sent you a PM

Thanks

Thierry