Radioear Model A-28 Vacuum Tube Hearing Aid
The Radioear model A-28 was a table-top model vacuum tube
hearing aid that ran on house current. It was manufactured by E. A.
Myers & Sons of Pittsburg, PA in 1930.
This hearing aid was a "heavy beastie" weighing in at 8˝ lbs. It measured 9”
wide by 6⅞" high by 4⅞" deep.
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The double carbon transmitter (microphone) is located in an opening
in the bottom front of the hearing aid (right).
The knob at the left was the volume control/on-off switch. The knob
can be set to any level between 10 and 100.
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The Model 28-A used two large vacuum tubes—a 471-B and a 433 or
equivalent. The vacuum tubes now in this hearing aid are a 171-A and a
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The inside back showing the position and type of the original tubes.
The tube on the left was originally a De Forest Audicon 471-B or
equivalent while the tube on the right was originally a De Forest
Audicon 433 or equivalent. |
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The magnetic receiver (earpiece) and power cord were stored in a small
compartment in the top front of the hearing aid.
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