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.

 

Hybrid Vacuum Tube/Transistor Hearing Aids

Sonotone 1010 Hybrid Hearing Aid

The Sonotone 1010 hybrid transistor hearing aid was manufactured by  Sonotone Corporation of Elmsford, NY. It was the very first commercial hearing aid to use a transistor. It came out on December 29, 1952. At that time it sold for $229.50.

The Sonotone 1010 was a hybrid hearing aid as it used 2 vacuum tubes and a single transistor as the output stage.

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. It weighed 3.1 oz. (88 g) without the batteries.
 

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Front view of the Sonotone Model 1010 hybrid transistor hearing aid.

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.

As a result, 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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Close-up view of the upper front of the Sonotone Model 1010 hybrid transistor hearing aid showing the microphone grill and the wire pocket clip below it. Later hearing aids had a 4-pointed star in the center of the microphone grill.

 

 

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Rear view of the Sonotone Model 1010 hybrid transistor hearing aid showing the swing up battery compartment door (bottom half).

 

 

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When you swung up the battery door of the Sonotone Model 1010 hybrid transistor hearing aid, on the inside of the battery door you could see the name of the manufacturer (Sonotone) and the model number (1010).

 

 

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View of the battery compartment of the Sonotone Model 1010 hybrid transistor hearing aid. The "B" battery fit in the back section and the "A" battery was at the front.

On the bottom of the "A" battery compartment  is a red A+ and a red arrow pointing to the right indicating the position of the positive terminal of the "A" battery.
 

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Close-up view of the battery compartment of the Sonotone Model 1010 hybrid transistor hearing aid showing the 15 volt Eveready 504E "B" battery (rear) and the Mallory RM-401 (Type "N") 1.4 volt mercury "A" battery (front).

 

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At the rear of the battery compartment of the Sonotone Model 1010 hybrid transistor hearing aid there were two 2-position switches.

The one on the left is labeled "HI" and has positions "B" and "A". The one on the right is labeled "LO" and has positions "1" and "2". Presumably they are for high frequency emphasis and for low frequency emphasis respectively.

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Close-up view of the rear wall of the battery compartment of the Sonotone Model 1010 hybrid transistor hearing aid showing the location of the positive terminal of the "B" battery (B+), the serial number (302836) (center) and stamped about the serial number are the words, "See patent notice in instruction book".

 

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Right side view of the Sonotone Model 1010 hybrid transistor hearing aid. The volume control is at the right.

 

 

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Left side view of the Sonotone Model 1010 hybrid transistor hearing aid showing the optional external microphone jack (two square holes center). At the left i the on-off switch.

 

 

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Top viiew of the Sonotone Model 1010 hybrid transistor hearing aid showing the volume control (left), the receiver cord plugged in (center) and the 3-position switch (right). Presumably the 3 positions are off (down), t-coil (mid) and on (up—shown).

 

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Top view of the Sonotone Model 1010 hybrid transistor hearing aid showing the receiver cord plug (bottom) and the 2-hole receiver cord jack (center).

 

 

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Close-up view of the receiver of the Sonotone Model 1010 hybrid transistor hearing aid and the receiver cord plug (shown unplugged). Note that the holes and plug pins are of different diameters so you could only plug them in the correct way.

 

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Rear view of the receiver of the Sonotone Model 1010 hybrid transistor hearing aid with the receiver cord plugged in.

 

 

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View of the receiver of the Sonotone Model 1010 hybrid transistor hearing aid showing how the hard plastic ear mold snapped to the nubbin in the center of it.

 

 

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Side view of the receiver of the Sonotone Model 1010 hybrid transistor hearing aid with the hard plastic ear mold snapped to it.

The ear mold did two things. First, it held the receiver tightly to the ear. Second, it fit air-tight to prevent any sound escaping from the ear canal which would cause loud feedback (squealing/whistling sound).

 

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Here is an excerpt from the March, 1953 issue of Fortune magazine showing that the Sonotone 1010 was the first hearing aid to ever use a transistor.

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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Here is an excerpt from page 205 of the book, "Crystal Fire: The Birth of the Information Age" by Michael Riordan, also confirming that the Sonotone was the first hearing aid to use a transistor.

 

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Here is an advertisement from the Syracuse Herald Journal of December 30, 1952 again confirming that the Sonotone 1010 was the first hearing aid to use a transistor.

 

 

 

 

 

 

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The Sonotone Model 1010 hybrid transistor hearing aid in its original case.

The Sonotone Model 1010 hearing aid, 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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The Sonotone design on the inside of the lid of the Sonotone Model 1010 hybrid transistor hearing aid case.

 

 


 

 

The case of the Sonotone Model 1010 hybrid transistor hearing aid. The case measured 3⅞ x 3⅞" x 1½" (9.9 x 9.9 x 3.8 cm).

 

 


 

 

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