Siemens/Fortiphone Model M-22 "Booster Flat" Carbon Hearing Aid
The Siemens/Fortiphone Model M-22 "Booster Flat" carbon hearing aid
was made in 1925. The actual hearing aid was made by Siemens & Halske A.
G. of Germany,
while the resonant black leatherette-covered case was made by Fortiphone
Ltd. of London, England. Fortiphone put the hearing aid in the case and
sold it under the Fortiphone trade name.
The case measured 7½" x 5¾" x 3¼" deep. The hearing aid and case
together weighed just over 1¼ pounds without the battery.
The double carbon microphones measured 4¾" x 2⅜" x 7/16" thick. |
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Front view of Siemens/Fortiphone Model M-22 hearing aid microphone
showing the on-off switch between the two microphones. This switch can
also be accessed through the hole in the front center of the case when
using the hearing aid in the case.
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Back view of Siemens/Fortiphone Model M-22 hearing aid microphone. The
black paint is almost all worn off. Engraved on the back just below the
leather button hole are the words "Siemens & Halske A. G. Germany"
Near the bottom is the serial number "10957" and the letter "N" below
it.
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Front view of Siemens/Fortiphone Model M-22 hearing aid volume control.
The black paint is mostly worn off showing its brass construction.
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Back view of Siemens/Fortiphone Model M-22 hearing aid volume control
showing the pocket clip.
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Top view of Siemens/Fortiphone Model M-22 hearing aid carbon amplifier.
The amplifier plugged directly into a battery. This hearing aid could
use any of the 3 or 4½ volt batteries in use at this time such as the
Fortiphone No. 3-S battery.
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Rear view of Siemens/Fortiphone Model M-22 hearing aid carbon amplifier.
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The receiver and stock ear mold of the Siemens/Fortiphone Model M-22
hearing aid.
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View of stock ear mold (left) and receiver of the Siemens/Fortiphone
Model M-22 hearing aid. The ear mold snapped into the hole in the
receiver.
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The microphone of the Siemens/Fortiphone Model M-22 hearing aid had a
leather button-hole attached to the back. This way the microphone could
be attached to any button on the wearer's shirt. Alternately, a black
ribbon could be threaded through the button hole and worn as a lanyard
around the wearer's neck.
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The Siemens/Fortiphone Model M-22 hearing aid microphone had a swing out
"stand" (bottom center) to hold it vertical when placed on a table when
it was not being used in its case.
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Bottom view of Siemens/Fortiphone Model M-22 hearing aid microphone
showing the stand swung out.
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Bottom view of Siemens/Fortiphone Model M-22 hearing aid microphone
showing the swing out stand folded up.
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The Siemens/Fortiphone Model M-22 hearing aid in its original resonant
case.
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Outside view of the Siemens/ Fortiphone Model M-22 hearing aid
resonant case.
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