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
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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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