science · 29 December 1952 · 72 years ago
In 1952, the first transistor hearing aid went on sale, the model 1010 manufactured by the Sonotone Corporation in Elmsford, NY, U.S. It weighed 3.5-oz, measured 3"x1.5"x0.6" and cost $229.50 (about $1500.00 today). It was a hybrid device consisting of two sub miniature pre-amplifier tubes and a single transistor as the final audio amplifier to benefit from the low power consumption of transistors. The reason for the hybrid design was that the first junction transistors had signal to noise ratios which were inferior to tubes. Within months, transistor production techniques were improved largely eliminating noise, so the hybrid model was shortly discontinued.
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