[Boatanchors] PERMANIC Microphone

[KA9EGW]

I googled it, and found an abstract about a psychology experiment which
chose that mic for the setup because it was inexpensive and because it
"requires no exciting voltage".  

Looked at it on eBay and it looks like just phone tips for output.

Sounds like a crystal mic, huh?

-----Original Message-----
From: boatanchors-bounces at puck.nether.net
[mailto:boatanchors-bounces at puck.nether.net] On Behalf Of Mike Langner
Sent: Wednesday, March 09, 2011 8:43 PM
To: 'Bob Peters'
Cc: boatanchors at puck.nether.net
Subject: Re: [Boatanchors] PERMANIC Microphone

Hello !

Let me guess.

Early broadcast dynamic microphones used a DC current operated field coil to
make the magnetic field.

Indeed, in the very early days, this current would cause the microphone to
become quite warm, hence the phrase "hot mic!"

I bet this is what you have.  If so, it's a great part of broadcasting
history!!

Mike/
K5MGR

(lifelong broadcast engineer -- my career started in 1958!)
____________________________________________________


Mike Langner
929 Alameda Road NW
Albuquerque, NM 87114-1901

(505) 898-3212 home/home office
(505) 238-8810 cell
mlangner at swcp.com

-----Original Message-----
From: boatanchors-bounces at puck.nether.net
[mailto:boatanchors-bounces at puck.nether.net] On Behalf Of Bob Peters
Sent: Wednesday, March 09, 2011 7:28 PM
To: boatanchors at mailman.qth.net; boatanchors at puck.nether.net; 'Discussion of
AM Radio in the Amateur Service'
Subject: [Boatanchors] PERMANIC Microphone

Does anyone on here know what a PERMANIC MICROPHONE is ???? I just bought
one of e bay...Manufactured by Quam the Speaker company. No one at Quam has
ever heard of it...It looks like about
1940 vintage... it is NOT a speaker...IDEAS???

Bob W1PE

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