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.

 

Body Type Transistor Hearing Aids

Maico Model O "Transist-Ear" Transistor (Body) Hearing Aid

The Maico Model O "Transist-Ear" transistor hearing aid was manufactured by Maico Electronics, Inc. of Minneapolis, MN.  The name "Maico" was derived from the initials of the Medical Acoustic Instrument Company.

This was the world's first all-transistor hearing aid and used 3 transistors. It came out in early January, 1953.

The Maico Model "O" had rather a strange shape—wider than tall. Its chrome case measured 2⅝" x 1⅞" x 11/16" thick (6.7 x 4.0 x 1.8 cm) and weighed 3.1 oz. (88 g) without the battery.

 

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Front view of the Maico Model O "Transist-Ear" transistor hearing aid.

Maico could have been the very first to produce a hearing aid using a transistor. They had this Model "O" all-transistor aid ready for production in late 1952, but decided to do more testing before releasing it to the public. Then, on December 29, 1952, Sonotone surprised Maico and came out with its hybrid Sonotone Model 1010 that used 1 transistor and 2 vacuum tubes.

Maico decided to immediately end all testing and start production on this all-transistor hearing aid which they did in early January, 1953. Thus Maico holds the honor of bringing out the first all-transistor commercially available hearing aid.

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The Wall Street Journal of January 9, 1953 reported that the Maico Transist-Ear (Model O) was the first all-transistor hearing aid to be released to the public.

A special thank you to Dr. Rick Hirsch for his research into searching out these newspaper clippings to establish Maico's first all-transistor hearing aid status.

 

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A few days later, on January 13, 1953, the Daily Boston Globe reported that the Model O (Transist-Ear) was the first all-transistor hearing aid.

 

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The Times News of January 27, 1953 also confirmed that the Transist-Ear was the first all-transistor hearing aid.

 

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Another advertisement from 1953 confirming that the Transist-Ear was the first all-transistor hearing aid.

 

 

 

 

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Close-up view of the front of the Maico Model O "Transist-Ear" transistor hearing aid showing the gold-colored microphone grill situated between the two pocket clips. Diagonally across the microphone grill is the name "MAICO".

 

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Rear view of the Maico Model O "Transist-Ear" transistor hearing aid.

The two dark holes (bottom left and mid right) are access ports to the two frequency response screws. These holes allowed the screws to be turned without taking the hearing aid apart. These screw "switches" allowed the audio frequency range to be adjusted to the users specific needs.

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Inside rear view of the Maico Model O "Transist-Ear" transistor hearing aid showing what the world's first completely transistor hearing aid looked like from the inside. Mounted on the circuit board are three Raytheon CK718 transistors (left mid, top right and bottom right of center).

The battery compartment is the large metal gizmo in the middle. The volume control wheel is at the top left.

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Inside ront view of the Maico Model O "Transist-Ear" transistor hearing aid showing the circuit board and its various resistors and capacitors. The large round thing in the center is the microphone.

 

 

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Top view of the Maico Model O "Transist-Ear" transistor hearing aid. The volume control/on-off switch is at the left and the 2-hole receiver cord jack is at the right.

Note that the holes are of unequal diameter to ensure correct polarity of the receiver cord plug.

 

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Top view of the Maico Model O "Transist-Ear" transistor hearing aid showing the receiver cord plugged into the hearing aid body.

 

 

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View of the front right corner of the Maico Model O "Transist-Ear" transistor hearing aid showing the volume control wheel/on-off switch. This was the only user control on this hearing aid.

 

 

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Bottom view of the Maico Model O "Transist-Ear" transistor hearing aid showing the black plastic battery compartment door in the center.

 

 

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Close-up view of the battery compartment door of the Maico Model O "Transist-Ear" transistor hearing aid showing the serial number (66917) stamped into it. Below the serial number is the model (Transist-Ear) and below that is the company name (Maico Co. Inc.) and location (MPLS standing for Minneapolis, MN).

 

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Bottom view of the Maico Model O "Transist-Ear" transistor hearing aid showing how the battery compartment slid out.

 

 

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Bottom view of the Maico Model O "Transist-Ear" transistor hearing aid showing the No. 625 mercury battery in the battery compartment.

At long last, hearing aid wearers were given a break through the elimination of the relatively expensive "B" battery required to power their vacuum tube hearing aids.

 

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Close-up bottom view of the Maico Model O "Transist-Ear" transistor hearing aid showing the battery compartment with battery in it being slid back into the hearing aid body.

 

 

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Close-up view of the receiver of the Maico Model O "Transist-Ear" transistor hearing aid and the receiver cord plug (shown unplugged).

 

 

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Rear view of the receiver of the Maico Model O "Transist-Ear" transistor hearing aid with the receiver cord plugged in.

 

 

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View of the receiver (left) of the Maico Model O "Transist-Ear" transistor hearing aid showing how the hard plastic ear mold (right) snapped to the nubbin in the center of it.

 

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Side view of the receiver of the Maico Model O "Transist-Ear" 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 (a loud squealing/whistling sound).

 

 

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