Hugh Hetherington Hearing Aid Museum
Hugh Hetherington Hearing Aid Museum

The Hearing Aid Museum

Hearing Aids of all types—Ear Trumpets, Carbon Hearing Aids, Vacuum Tube Hearing Aids, Transistor Hearing Aids, Body Hearing Aids, Eyeglass Hearing Aids and much more!

Home Enter the Museum About Us Contact Us

FREE Subscription to:
Hearing Loss Help
The premier e-zine for people with hearing loss

Your email address
will never be
rented, traded or sold!

Your First Name:
Your E-mail:
Search this site:

 Results per
 page

 all words
 any words


Click on the "General Information" button (top button above) for an overview and general information on this category of hearing aid.

 

Carbon Hearing Aids: 1900-1939

Siemens Model M-22 Carbon Hearing Aid

The Siemens Model M-22 carbon hearing aid was made by Siemens & Halske A. G. of Germany in 1925.

There appear to have been at least two versions of the Model M-22, this one and the M-22 "Booster Flat".

 

Click picture for larger view

 

Next

 
The front of the Siemens Model M-22 hearing aid carbon microphone. Each microphone grill consists of an outer circle of 12 diamond-shaped cut-outs and an inner row of alternating diamond-shaped cut-outs and small circles.

The double carbon microphones measured 4¾" x 2⅜" x 7/16" thick.

Note the leather button-hole (left). This way the microphone could be attached to any button on the wearer's shirt. Alternately, a ribbon could be threaded through the button hole so the hearing aid could be worn on a lanyard around the wearer's neck.

Click picture for larger view

 
Rear view of Siemens Model M-22 hearing aid microphone. Engraved on the back just below the leather button hole are the words "Siemens & Halske A. G. Germany"

 


Click picture for larger view

 
Front view of Siemens Model M-22 hearing aid on-off switch shown in the "on" position. There was no volume control on this model.


Click picture for larger view

 
View of battery plug (left) and the top of a battery (right) showing the battery jacks. The pins and jacks were of different sizes so the plug could not be inserted with the polarity reversed.


Click picture for larger view

 
The Siemens Model M-22 carbon hearing aid plugged into a 4½ volt Fortiphone No. 3-S battery.

 


Click picture for larger view

 
The receiver and stock ear mold of the Siemens Model M-22 hearing aid. The wire ear hook helped it stay in place.


Click picture for larger view

 
View of stock ear mold (left) and receiver (right) of the Siemens Model M-22 hearing aid. The ear mold snapped into the hole in the receiver.
 


Click picture for larger view

 

Side view of the Siemens M-22 receiver showing the patent number. It reads, "U.S. patent No. 1,406,510".

 


Click picture for larger view

 

Bottom view of the Siemens Model M-22 carbon microphone showing the "foot" swung out so it could stand upright on a table instead of laying flat.

When the foot is swung out it reveals the Roman numeral II and the number 264. This likely indicates this is the sub model II of the M-22 line. The 264 may be the serial number as there is no serial number visible as is the case with the Model M-22 "Booster Flat".

 


 

Click picture for larger view

 

(If a larger picture doesn't appear, you may have to turn your pop-up blocker off)