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 AO (Transist-Ear) Transistor (Body) Hearing Aid

The Maico Model AO was manufactured by Maico Electronics, Inc. of Minneapolis, MN in 1960.  The name "Maico" was derived from the initials of the Medical Acoustic Instrument Company.

The Model AO was a 6-transistor hearing aid with AGC (automatic gain control). It also sported a T-coil. The case was stainless steel over black plastic. It measured 2⅝" x 1¾" x ⅝" thick.

The cord and receiver (earpiece) are shown to the right. An ear mold (not shown) needs to be snapped to the receiver.
 

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Top view of the Model AO. It was a bit unusual as both the volume control and a second control wheel were in the same top right corner—the volume control to the back and the other control wheel to the front. This control wheel is labeled "R", "W" & "T". Since this model has a T-coil, the "T" probably refers to the t-coil mode, the "R" could stand for "regular" (the normal microphone mode). The "W" is a mystery at the moment.

The receiver (earpiece) cord jack is on the left.

Notice that the microphone was located on the top (center), not on the front as was more commonly done with body aids.
 

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The Maico Model AO used two 1.4 volt Number 401 mercury batteries.

Notice above the batteries, the screws for adjusting the "response" and for turning on "compression". This aid only had two positions for compression—on or off.

Under the name Maico (and above the top battery) is a little tab labeled "140". It has contacts that make contact with the hearing aid when it is pushed in. (We don't know its function.)

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