[AMRadio] D104 element Rebuilding

Jim candela jcandela at prodigy.net
Sun Nov 19 23:09:47 EST 2006

I am either too old or too young to have ever seen a D104 ad.


Jack, Here is the ad from 1933 by Astatic:

elements made from Rochelle Salts, (Sodium Potassium Tartrate)



It was about this time that an old acquaintance, Mr. Charles E. Semple, of
Cleveland, who had been visiting his "ham" friends frequently, invited them
to pay him a visit. With a background of phonograph and loud speaker
experience, Mr. Semple was then occupying bench space in the Brush
Laboratories, experimenting with elements made from Rochelle Salts, (Sodium
Potassium Tartrate). Through Mr. Semple, the two visitors met A.L. Williams,
electrical and mechanical engineer, and Dr. C.B. Sawyer, scientist, who
demonstrated to them the action of these new elements in relation to
microphones, phonograph pickups, speakers, recording heads, earphones, and
other devices where it was desired to transform mechanical energy into
electrical energy or the reverse. Here, it seemed, they had found the answer
to a simple, low cost, dependable "mike" for the ham rig."

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