Audivox Model 77 "Extra" Transistor (Body) Hearing Aid
The Audivox Model 77 "Extra" transistor body hearing aid
was made by Audivox, Inc. of Boston, MA in 1957.
This hearing aid had 5 transistors and utilized a push-pull amplifier
circuit. It measured 2 15/16" x 1⅞" x ⅝" (7.4 x 4.7 x
1.6
cm) and weighed 3.1 oz (88 g) without batteries.
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Front view of the Audivox Model 77 "Extra" transistor body hearing aid
showing its chrome front. Note the wire pocket clip.
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Close-up of the upper front of the Audivox Model 77 "Extra" transistor body hearing aid
showing the microphone grill (hole in center) set in an attractive graphic design.
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Top view of the Audivox Model 77 "Extra" transistor body hearing aid showing the
the on-off/volume control wheel (left), the T (t-coil) M (microphone)
switch (center) and the 3-position tone control wheel (right) (see below for description). |
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Close-up of the top left corner of the Audivox Model 77 "Extra" transistor body hearing aid showing the
3-position tone control—L (low-frequency emphasis), N (normal tone) and H (high-frequency
emphasis).
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Rear view of the Audivox Model 77 "Extra" transistor body hearing aid showing the battery door on the lower half of the back.
The battery door swung up from the bottom.
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Bottom view of the Audivox Model 77 "Extra" transistor body hearing aid showing the
recessed thumbnail slot (center) to pull open the battery compartment door.
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View of the inside of the battery compartment lid of the Audivox Model
77 "Extra" transistor body hearing aid battery compartment showing the
warning "Important" and "Remove battery when not in continuous use".
Otherwise, the batteries tended to corrode in place and destroy the
battery compartment.
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View of the battery compartment of the Audivox Model 77 "Extra" transistor body hearing aid
with the battery compartment door opened. It swung up from the bottom.
The left side shows the serial number (R4676) in white numbers. Below that is the
manufacturer's information (Audivox, Boston, Mass, USA) and near the
bottom,
the model number (Model 77).
Above the model number is a two position (red or blue dot) red screw of
unknown function.
On the right note the twin battery slots. This was a higher-powered aid
and took not one, but two, batteries.
Also note the black vinyl plastic "tab" that went under the batteries to make it
easy to remove them. |
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View of the Audivox Model 77 "Extra" transistor body hearing aid
battery compartment showing how pulling up on the black vinyl tab (right
side) dislodged the batteries so you could easily replace them.
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View of the battery compartment of the Audivox Model 77 "Extra" transistor body hearing aid showing the two
Type "N" or 401 batteries in place. This aid used two 1.4 mercury
batteries such as these
Rayovac
RP-401 batteries.
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Lower right side view of the Audivox Model 77 "Extra" transistor body hearing aid showing the two-holed jack for the receiver cord and the
plug on the end of the receiver cord. Both holes and prongs were the
same size so it could be plugged in either way.
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Right side view of the Audivox Model 77 "Extra" transistor body hearing aid showing the receiver cord plugged into the body.
Note that the plug should be plugged in as shown so the receiver cord would
not have to have a sharp bend in it when used in a pocket.
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Front view of the Audivox Model 77 "Extra" transistor body hearing aid receiver showing the the part number—020 (top) and
?2-7 (bottom). The ear
mold snapped onto the nubbin in the center.
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Close-up of the back of the Audivox Model 77 "Extra" transistor body hearing aid receiver. The receiver cord
is plugged in (right).
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Close-up view of the Audivox Model 77 "Extra" transistor body hearing aid receiver and ear mold
unsnapped.
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Side view of the Audivox Model 77 "Extra" transistor body hearing aid receiver showing the clear plastic ear mold
(left) snapped to the
receiver (right).
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