Acousticon Model A-310 Hybrid Hearing Aid
The Acousticon Model A-310 was produced by Dictograph Products
Corporation in 1953 and is a sample of the early use of a transistor in
a hearing aid.
This second Acousticon vacuum tube-transistor hybrid hearing aid was much smaller than it’s
A-300 predecessor. It had a gold anodized aluminum case and weighed only 4 oz. with batteries.
The A-310 measured 2½” by 1¾” by ⅞”.
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Internal view of the Model A-310 from the front.Notice the t-coil
(coil of wire at the bottom).
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Internal view of the Model A-310 from the rear. This hearing aid used two CK549DX
miniature hearing aid vacuum tubes (top center) with a single CK718 transistor
(top left) for the
output stage.
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This
model included a telecoil that was activated by rotating the (blue) receiver
plug on the top of the hearing aid. The oval cutout to the left of the
blue switch is the microphone opening. For some reason, the microphone
was placed here instead of the normal place on the front of the hearing
aid. |
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Read the
manual for the Acousticon Model A-310 hybrid vacuum tube/transistor
hearing aid. |
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The Acousticon A-310 used a 15 volt 504E "B" battery (bottom) and an 1.4
volt RM-1 mercury "A" battery (top right).
Note: by substituting a transistor for one of the vacuum tubes,
filament current drain was reduced by 1/3 resulting in a slightly longer
battery life and reduced cost to the user. Hybrid hearing aids were only
produced for about a year as fully transistorized hearing aids quickly
took over the market.
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