Microtone Model T-6 "Lifetime" Vacuum Tube Hearing Aid
The Microtone Model T-6 "Lifetime" was produced by Microtone Co. of St.
Paul, MN in 1948.
It was a 4 vacuum-tube hearing aid measuring 3¾" x 2¼" x 1"
thick. It
weighed 6¾ oz. without the batteries.
The microphone grill (top center) was covered by a cream-colored
fabric with the Microtone crest in the center. This attractive hearing
aid had a white plastic case with embroidered trim.
The Microtone Model T-6 sold for $229.50 in 1950. Here is an
original
invoice for the T-6. Something must have gone wrong and the hearing
aid was replaced under warranty as this
warranty
card shows a different serial number than the invoice. The pictures
here are of this replacement aid as the serial numbers match.
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Top view of the Microtone Model T-6 "Lifetime" hearing aid showing
the receiver plug (right center), and the volume control (bottom left),
and on-off/tone control lever (bottom right). "Off" is the upright
position. In the middle position both low and high tones are amplified
equally (what they call "high fidelity", and in the low position (shown)
low tones are suppressed and the higher tones are accentuated. The pocket
clips are at the left and right sides (top).
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Rear view of the Microtone Model T-6 "Lifetime" hearing aid showing
the manufacturer's name (Microtone) and the model name (Lifetime). You
can read the
Microtone T-6 manual that came with this hearing aid.
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The whole back of the case swung down from the top revealing the battery
compartment of the Microtone Model T-6 "Lifetime" hearing aid.
The round center compartment held an
RM-4 1.4 volt mercury "A" battery, and the lower compartment, a size
412E 22½ volt "B" battery. The 4 vacuum tubes are stacked (2 on
each side) under the cream housing on each side of the "A" battery.
At the very top (center) is the serial number (58650).
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Inside view of the battery compartment door of Microtone Model T-6
"Lifetime" hearing aid showing the manufacturer, "The Microtone
Company/Minneapolis, Minnesota/ U.S.A." (bottom). When the back is
closed, the metal assembly in the center makes contact with the back of
the "A" battery and transfers power to the internal circuits via the
clips in the top left and right corners of this assembly. |
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Close up of the battery meter of the Microtone Model T-6 "Lifetime"
showing the two meter scales. The upper one ranges from 0 - 2 volts for
testing the "A" battery, and the lower one ranges from 0 - 50 volts for
testing the "B" battery. To test the batteries, you put them in the
appropriate slots (see below picture) then pressed one of the two
buttons (right side) labeled "A" (upper) and "B" lower to obtain the
reading for the "A" or "B" battery. |
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Below the battery meter are two slots for "reconditioning" the
batteries. The upper one is for the "A" battery, and the lower one for
the "B" battery. The Microtone T-6 "Lifetime" used what they called
the "Micro-Mizer" to "recondition" the batteries overnight after you
used them all day. By so doing you could extend the effective life of
the "A" battery 3 to 4 times, and the "B" battery up to 5 times its
normal life. Here is the
instruction card on how to use the Micro-Mizer. |
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The Microtone T-6 "Lifetime" (right) in its dresser-top case and the
battery meter/Micro-mizer (left). There is an interlocking switch in the
top left corner that prevents the Micro-mizer from working when the lid
is open. |
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Outside view of the Microtone T-6 "Lifetime" dresser-top case.
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