"Joel Koltner" wrote in message
...
Are crystal earphones called that because they're used with crystal
radios, or because they really do have some sort of crystal in them (seems
unlikely)?

---Joel



The crystal earphone is called that because it does contain a crystal,
similar to some microphones.

The crystal in a crystal radio is the diode that does the conversion from RF
to AF. It started off years ago as a real crystal. A semiconductive
mineral crystal, usually lead sulfide (galena) or cadmium sulfide.

The impedance of the headphone is pretty much meaningless.
The sensitivity is critical. Impedance matching can be done with
high quality audio interstage transformers. The most popular
headsets are made from sound powered Deck-Talkers used on
WWII era military ships. They have balanced armatures and
are extremely sensitive, and very low impedance.

Pete K1ZJH

Ben Tongue's website offers exellent engineering analysis
and practical information on crystal set design:

http://www.bentongue.com/xtalset/xtalset.html

For good practical discussions try TheRadioBoard.com.
Lot's of xtal set experimenters over there to answer
questions...

Pete k1zjh

Unca Pete wrote:
Ben Tongue's website offers exellent engineering analysis
and practical information on crystal set design:

http://www.bentongue.com/xtalset/xtalset.html

For good practical discussions try TheRadioBoard.com.
Lot's of xtal set experimenters over there to answer
questions...

Pete k1zjh



Was gonna recommend the same. Along the lines of good 'crystal radio'
headphones some of the guys have found some of the little piezo devices
make for a very sensitive, high-impedance DIY headfone project. I think
one of the guys is selling them as a kit, with shooter's muffs included.
Haven't tried them myself but the reports are very favorable.

-Bill