Zenith Model B3A "Radionic" Vacuum Tube Hearing Aid
The Zenith Model B3A "Radionic" vacuum tube hearing aid was
manufactured by the Hearing Aid Division of the Zenith Radio Corporation
of Chicago, IL beginning in July, 1944.
The black plastic case measured 5⅛” by 2¾” by ⅞” thick, and weighed 8⅞
oz. without the batteries.
The microphone grill was the series of 9 horizontal slots (top center). Notice the large "Z" on the lower front face.
This was a two-piece hearing aid as it connected to external
batteries (battery cords bottom left).
The Zenith Model B3A used three vacuum tubes. The third vacuum tube
likely supplied more power so this hearing aid could adequately drive
bone-conduction transducers. The "B" in the "B3A"
refers to a bone-conduction transducer. The
bone-conduction transducer is missing.
It sold for $50.00. |
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Top view of the Zenith Model B3A showing the 4-position (2, 3, 4 and the
lever straight up for position 1) tone control (left), the large volume
control wheel (center) and the on-off switch (right).
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Bottom view of the Zenith Model B3A showing the battery jack (left), and
the bone conductor transducer jack (right). The "butterfly" in the middle swivels 90
degrees to hold the plugs in place.
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Close-up view of the Zenith Model A3A-B3A battery plug. The battery plug had
the heavy battery wires attached to it. In contrast to the 3-pin plugs
of the Model A2A, with the Model B3A Zenith made the battery plug
with 4 pins so there was no confusion which plug went where.
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Close-up view of the Zenith Model B3A bone conductor transducer plug. This plug
had the thin cord attached to it.
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Close-up view of the Zenith Model B3A battery plugs. The 3-pronged plug went into the "B" battery (left) and the 2-pronged plug fit the "A"
battery (right).
Here are examples of batteries that would work with the Zenith Model
B3A.
The
Zenith Z-30 "B" battery (left) put out 45 volts, while the
Zenith "A" battery (right) put out 1½ volts.
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Back view of the Zenith Model B3A hearing aid. The two holes (top
center) were for snapping in the pocket clip if you wanted it on the
back instead of the front as is the case with this aid.
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Close-up view of the back of the Zenith Model B3A showing the
information engraved there. It reads, "ZENITH RADIO CORP. U.S.A.",
"BONE-AIR", "FOR USE WITH MODEL A3A-B3A", Serial No.
BC-020057" and " Pats. applied for". It appears that the physical hearing aid body (Model A3A-B3A) was
identical whether boxed in the green box as the Model A3A-B3A
or in a blue box as the Model B3A. The B3A came with just the bone conduction
transducer and not an air-conduction receiver. |
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The Zenith Model B3A "Radionic" hearing aid in its original box. |
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The top of the original box for the Zenith Model B3A "Radionic" hearing aid
showing its model number. |
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Top view of the Zenith Model B3A "Radionic" hearing aid's original box.
Note that the Radionic A3A-B3A had a green box, while the identical
hearing aid but with just a bone conduction transducer was called the Model B3A,
and came in
a blue box (shown).
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