By: Ardis E. Parshall - May 01, 2015 In March 1922, the Improvement Era carried a short article by editor Edward H. Anderson about the exciting possibilities of the newly invented vacuum tube amplifier – those glass tubes seen inside antique radios and other early- to mid-20th century gadgets. Such tubes amplified electric signals to such an extent that for the very first time, the human voice could be heard by telephone from one coast...
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