Sonotone 1010 Hybrid Hearing Aid
The Sonotone 1010 hearing aid was very likely the first commercial
hearing aid to use a transistor. It came out on December 29, 1952. At
that time it sold for $229.50.
Actually, the Sonotone 1010 was a hybrid as it used
2 vacuum tubes and a single transistor as the output
stage.
The development of this hearing aid represented the
first step in the move from vacuum tubes to all-transistor hearing aids.
The metal case measured 3" by 2¾" by about ½" thick.
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Early transistors had problems with their signal-to-noise ratio. As a
result, Sonotone used two vacuum tubes in the first
stages of the circuit, and utilized a transistor in the output stage.
This
combination maintained a high signal-to-noise ration while reducing the
operating current required. This resulted in reduced battery operating costs
for the user.
The problems with the early production transistors were
quickly solved, and most hearing aid manufacturers were producing all-transistor hearing aids by the end of 1953.
Vacuum tube hearing aids
quickly disappeared from the market. This resulted in significant reductions
in battery costs for hearing aid users because the high voltage "B" battery was no
longer needed.
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This is the Sonotone 1010 in its original box. Incidentally, the
Sonotone Model 1010, although a hybrid, was awarded the Audio
Engineering Award of Excellence in 1953, even winning over all-
transistor hearing aids. Here is the
report by the judging committee giving their reasoning. |
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These body-style hearing aids had a button receiver (earpiece) to
which a hard plastic ear mold snapped to hold the receiver to the ear. |
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The Sonotone 1010 used a type 401 mercury cell for the "A" battery
and a type 504 15 volt "B" battery.
There is much more information on the importance of transistors in
the development of hearing aids, and particularly this hearing aid
on
Bob McGarrah’s website.
If you are interested in the history of Sonotone International,
the maker of Sonotone hearing aids,
Roger Russell has a great website that details its history from its
beginnings in 1929 until its ultimate demise in 2005. There is also a
page giving some information on
some of the Sonotone hearing aids produced.
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Learn about
Aural Rehabilitation here.
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