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.

 

Vacuum Tube Hearing Aids: 1921-1953

Sonotone Model 531  Vacuum Tube Hearing Aid

The Sonotone Model 531 vacuum tube hearing aid was manufactured by Sonotone International, Inc. of Elmsford, New York in 1942.

The Sonotone Model 531 used two vacuum tubes. It weighed 6.2 oz. (176 g) without the batteries and measured 4 1/16" high x 2 3/16" wide by 13/16" thick (10.4 x 5.6 x 2.1 cm).

 

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Top view of the Sonotone Model 531 vacuum tube hearing aid showing the volume control/on-off switch.

 


 

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Front view of the Sonotone Model 531 vacuum tube hearing aid.

It was quite attractive with its shiny black plastic case with the pearlized inserts on the front.

 

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Upper front view of the Sonotone Model 531 vacuum tube hearing aid showing the attractive microphone grill and pearlized inserts below it.

The microphone grill of the Model 531 had 4 horizontal slots, whereas the microphone grill of the Model 533 had 5 slots.

 

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Rear view of the Sonotone Model 531 vacuum tube hearing aid showing the metal pocket clip (top).

 

 

 

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Top rear view of the Sonotone Model 531 vacuum tube hearing aid showing the name (Sonotone), U.S. patent number 1,679,532, "Made in U.S.A." and serial number (87612).

Nowhere on this aid is the model number shown.

 

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View of the top left corner of the back of the Sonotone Model 531 vacuum tube hearing aid showing the 4-position screwdriver adjustable tone control shown here in position 3.

 

 

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Bottom view of the Sonotone Model 531 vacuum tube hearing aid showing the 4-pronged battery cable plug (left) and the 2-pronged receiver cable plug (right).

 

 

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Bottom view of the Sonotone Model 531 vacuum tube hearing aid showing both plugs plugged into the aid. The plugs could only be plugged in one way as the pin sizes were different so you couldn't plug them in backwards.
 

 

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Close-up view of the  2-pronged "A" battery plug (left) and the 3-pronged "B" battery plug (right) of the Sonotone Model 531 vacuum tube hearing aid.

 

 

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Close-up view of the unplugged  2-pronged "A" battery plug (bottom) of the Sonotone Model 531 vacuum tube hearing aid and the top of a 1˝ volt Sonotone No. 800X "A" battery.

 

 

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Close-up view of the unplugged 3-pronged "B" battery plug (bottom right) of the Sonotone Model 531 vacuum tube hearing aid and the top of a 45 volt Burgess No. XX30E "B" battery.

 

 

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Rear view of the Sonotone Model 531 vacuum tube hearing aid receiver.


 

 

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Side view of the Sonotone Model 531 vacuum tube hearing aid receiver showing how the discrete pins plugged into the receiver.


 

 

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Side view of the Sonotone Model 531 vacuum tube hearing aid receiver and an early custom hard clear plastic ear mold.


 

 

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View showing how the ear mold snapped to the receiver. Here shown unsnapped.
 


 

 

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The Sonotone Model 531 vacuum tube hearing aid in its original leatherette carrying case.

 

 

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Close-up view of the top left corner of the inside of the lid of the case of the Sonotone Model 531 vacuum tube hearing aid revealing that Sonotone called these hearing aids by the generic name of "Audicle". It reads "Sonotone Audicle" and "Reg. U.S. Pat. Off."

 

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This card, in the pocket on the inside of the lid of the case of the Sonotone Model 531 vacuum tube hearing aid, specified a number of patents covering the design of this hearing aid.

 

 

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Outside view of the Sonotone Model 531 vacuum tube hearing aid's leatherette carrying case. The case measured 6⅝" x 4 5/16" x 1 13/16" (16.9 x 10.9 x 4.7 cm).

 

 


 

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