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!

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

 

Carbon Hearing Aids: 1931-1940

Gem Model 30 Standard "3" Carbon Hearing Aid

The Gem Model 30 Standard "3" carbon hearing aid was manufactured by The Gem Ear Phone Co. of New York, NY around 1930.

There were a number of early Gem carbon hearing aids. Since Gem didn't put model numbers on these aids, and since there are few, if any, records describing each model, it is impossible to know for sure which model is which. As a result, to differentiate different similar unmarked models in the museum, I have simply given a serial number in quotes (e.g. "3") to these unknown models. Thus this Gem carbon hearing aid is "3" version of what I think is the Gem Model 30 Standard carbon hearing aid.

This hearing aid was a pretty basic unit consisting of a microphone and a receiver connected by a single cord with an on-off switch in the cord. It was quite light and weighed 11.1 oz. (316 g) with the battery and only 3.7 oz. (106 g) without the battery.
 

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Front view of the microphone of the Gem Model 30 Standard "3" carbon hearing aid. The microphone grill consisted of two concentric rows of holes—16 holes in the outer row and 8 holes in the inner row. The center was a slot. The microphone measured 2⅜" in diameter by ⅞" thick (6.0 x 2.2 cm).

Around the rim of the microphone are the words "The Gem Ear Phone Co." and "New York".

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Rear view of the microphone of the Gem Model 30 Standard "3" carbon hearing aid showing the fiber volume control (black thumb wheel in center). Notice the small hole at the 1 o'clock position showing the volume level (6 in this case). Volume ranged from 1 to 9.

At the top of the volume control is a hole for threading a lanyard through so you could hang the microphone around your neck if so desired.

Note the words "Made in U.S.A." just above the volume control wheel.

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Side view of the microphone of the Gem Model 30 Standard "3" carbon hearing aid showing the raised black fiber volume control wheel. It had a serrated edge for ease of turning.


 

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Close-up view of the Gem Model 30 Standard "3" carbon hearing aid battery (left) and microphone (right). The pins are of slightly different size (the left pin is larger) so you could only plug them together the right way ensuring the correct polarity.

This hearing aid used a 3-volt carbon-zinc Gem 1A battery (left).

 

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Close-up view of the Gem Model 30 Standard "3" carbon hearing aid showing the microphone plugged directly onto the battery terminals.

 

 

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Side view of the Gem Model 30 Standard "3" carbon hearing aid. Notice that the prongs on the battery are set near the back (right side) instead of in the center of the top of the battery as was more common. This provided better stability for the hearing aid since the microphone was "front heavy". It also provided for a sleeker-looking hearing aid.

 

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Close-up view of the front of the on-off switch for the Gem Model 30 Standard "3" carbon hearing aid. It was located about 4½" (11.5 cm) from the microphone along the receiver cord. It's shown here in the "on" position.

The switch box was quite small and measured 1⅛" x 9/16" x ⅜" high (2.8 x 1.4 x 1.0 cm).

 

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Side view of the on-off switch of the Gem Model 30 Standard "3" carbon hearing aid.


 

 

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Front view of the receiver of the Gem Model 30 Standard "3" carbon hearing aid. This receiver was a bit unusual in that it was made of metal. Most of the time they were made of plastic. The stock ear tip screws out. (Presumably there were different diameters of ear tips to fit various sizes of ears.)

Note the wire ear clip to hold the receiver in your ear.
 

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Side view of the receiver of the Gem Model 30 Standard "3" carbon hearing aid.

The receiver measured 1" in diameter by 9/16" to the base of the stock tip (2.6 x 1.5 cm). It was relatively heavy weighing 0.8  oz. (24 g).


 

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Rear view of the receiver of the Gem Model 30 Standard "3" carbon hearing aid. Note the name "Ear-Gem" engraved near the top.

 


 

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The Gem Model 30 Standard "3" carbon hearing aid in its carrying case.


 

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The inside flap of the lid of the Gem Model 30 Standard "3" carbon hearing aid carrying case was embossed with the words, "The Gem Earphone Co." and "New York".


 

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Rear view of the carrying case of the Gem Model 30 Standard "3" carbon hearing aid showing the cut-out for the microphone grill. Thus, you could sit this hearing aid on a table and use it that way with the microphone and battery all neatly hidden away, instead of wearing it around your neck.


 

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Outside view of the carrying case for the Gem Model 30 Standard "3" carbon hearing aid. It was finished in black leatherette.

The case measured 8¼" x 3 1/16" x 2 1/16" deep (21.0 x 7.7 x 5.3 cm).

 


 

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