Acousticon Model A-45 Vacuum Tube Hearing Aid
The Acousticon Model A-45 was a "Teardrop" shaped,
two vacuum tube, two-piece hearing aid. It was made from 1940 to 1942 by the
Dictograph Corporation of New York.
The overall measurements are 4¼" by
2½" by 1" deep. This is one of the earliest Acousticon vacuum tube
hearing aids produced by the Dictograph Corporation. The two top
pictures show bone
conduction transducers.
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Another view of the Acousticon Model 45 showing the bone conduction
transducer on the headband. The transducer was placed on the bump behind
your ear where it vibrated your skull to transmit sound from the hearing
aid to the inner ear.
Bone conduction was quite popular in the 1930s and 1940s perhaps for
a couple of reasons. First, more people may have had conductive losses
than today as conductive losses are readily treated now.
Second, these early hearing aids didn't have the amplification needed
to push a signal through a clogged up middle ear like modern aids
can—hence the bone conduction transducer bypassed the clogged middle ear
and sent the signal straight to the inner ear. |
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The Acousticon Model 45 with the front cover removed so you can see
its insides. You can't see the two miniature vacuum tubes as they are
hidden by the big round microphone. However, you can see the wires
(pins) coming from the base of these tubes at 4 o'clock and 8 o'clock in
relation to the microphone disc. |
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This hearing aid could be used with either a 30 volt or a 45 volt
battery depending on the person's hearing loss. The higher voltage gave
greater amplification for more severe hearing losses. The Eveready "B"
battery at the right is a 45 volt battery.
The two pictures at the right show the Acousticon A-45 with air
conduction receivers. |
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A view of the Acousticon A-45 showing showing it hooked up to
a set of its batteries. The round battery is the standard 1.5 volt "D"
cell that provided the filament voltage to the vacuum tubes, while the
rectangular red (war) battery is a 30 volt battery to provide the "plate" voltage
of the vacuum tubes.
The two-pronged plug plugged into the "A" battery while the
three-pronged plug was for the "B" battery.
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The original box the Acousticon Model 45 came in.
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