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: 1900-1939

Radioear B-15 Carbon Hearing Aid

The Radioear B-15 carbon hearing aid, also known as, the Radioear Deluxe first appeared in 1934. It was manufactured by E. A. Myers of Pittsburg, Pennsylvania (later Radioear Corp.) and represents the ultimate sophistication in carbon hearing aids of the era.

The unit was packaged in a number of different configurations depending on the degree of hearing loss as determined by what was termed a Selex-A-Phone analysis. One such custom hearing aid sold for $140.00 back in 1939. Here is the original order form.

Here's a copy of the original warranty for this order.

The Selex-A-Phone was a master hearing aid equipped with a number of different transmitters, receivers and bone conductors and permitted the listener to try different combinations of these in order to determine his hearing requirements. The Selex-A-Phone was developed by Radioear in 1935. Here is a picture of the Selex-A-Phone.

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The Radioear B-15 hearing aid in its original carrying case. It consisted of the grey battery case and amplifier (top), the receiver or ear piece (middle) and the hearing aid microphone (bottom).

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A close up of the Radioear B-15 microphone/hearing aid. The top of the unit is at the left. Notice the volume control slider (shown in the quiet position) (left).

The large slots at the top (left) and bottom (right) allowed sounds to get to the microphone.

An interesting feature of this hearing aid was the telephone/voice switch on the front of the unit (slider on the right—shown in closed position). Normally, the sound was picked up by the large slots surrounding the carbon microphone. However, when the slider was moved to the telephone position, the four smaller slots in the middle of the hearing aid opened up so that a telephone receiver could be placed right over the top of the microphone.


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The Radioear B-15 could be equipped with a carbon (mechanical) amplifier unit called an intensifier (shown at right). This unit was capable of increasing the power of the hearing aid for people with more severe losses.

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The microphone could be plugged directly into the battery box (left), or the intensifier (center) could be plugged onto the battery box and the microphone plugged into the intensifier. (The microphone plug is shown on the right.)

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A black stock earmold (left) snapped onto the receiver or earpiece (right). The Selex-a-Phone had one each of the six or so standard-sized stock ear molds for the person to try for the best fit.

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The hearing aid could be powered by a standard 4˝ Volt hearing aid battery, or alternately with a special battery box which used 1˝ Volt flashlight batteries. When used with the battery box (shown right), the user could use either two or three “C” size flashlight batteries. A dummy shorting battery was supplied to fit in the place of the third battery when it was not used. (The left dark gray/green "battery" is the dummy.)

In quiet situations, the wearer might use two batteries (3 Volts), but when more power was needed, the battery voltage could be increased to 4˝ Volts by inserting a 3rd battery.

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The package also included a special battery meter (right) to test the batteries. This battery tester only had one lead (positive) so you placed the negative case of the battery against the battery case to complete the circuit.

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The front cover of the manual. Click here to read the 31-page manual (in pdf format).



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