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Crank It: 1925

June 29, 1925. "Dr. H.C. Hayes of U.S. Naval Research Lab, Bellevue, D.C." I'll bet that knob goes up to 11. National Photo Company glass negative. View full size.

June 29, 1925. "Dr. H.C. Hayes of U.S. Naval Research Lab, Bellevue, D.C." I'll bet that knob goes up to 11. National Photo Company glass negative. View full size.


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Optional Caption

In this rare 1946 photo taken by his then-partner Clayton "Doc" Kauffman, Clarence "Leo" Fender powers up his original Champ amplifier. Off camera is employee George Fullerton playing an early Fender lap-steel guitar.

Soon, a change in the circuitry to incorporate vacuum tubes allowed Fender to reduce the size of this amp to a much smaller 11″ x 12″ x 7-1/4″, yet many pro guitarists today choose to play through this ungainly and increasingly scarce model, citing clarity of tone and the ability to distort at higher output levels. A tweed-covered model was also available.

Happy machine

In a goofy way.

The Dr. would have been proud

The Gent in the Suit

is Dr. Harvey C. Hayes (1878-1968), the pioneering research physicist in underwater acoustics who served as superintendent of the Naval Research Laboratory's Sound Division from 1923 to 1952. At the time this photo was taken, Dr. Hayes's new sonic depth finder was enabling the first accurate and rapid mapping of the ocean floor. His development of one of the Navy's earliest operational Sonar systems and other work in underwater acoustics would play a major role in the eventual destruction of the German submarine fleet during World War II, and much of his work continues to influence oceanographic research and marine technology innovations worldwide.

M-G Set

The motor-generator set was most likely used to provide power for the transmitter tube's filament ("A+" voltage.) Tube of that era did not have indirectly heated cathodes and needed a source of pure DC at low voltage and high current. The only way to get that back in the day was either batteries or a DC generator.

Mercury rectifiers handled the high voltage, relatively low current "B+" voltage. The commutator of a DC generator would have a hard time dealing with several thousand volts.

A great look at some interesting equipment from the dawn of radio.


I always wondered how they made applesauce.

"Alright, Miss Lane"

"This bunker is lead-lined, so even Superman can't save you. Now talk... where did you hide those diamonds?"

Two questions:

1) What's behind that door that could be more dangerous than the rig Dr. Hayes is working on?

2) Why put a screen door between (presumably) two interior spaces?


A decade later, Charlie Chaplin, motivated by this photo, created the classic film "Modern Times".

Safety first

They wisely turned off the power to the transmitter before letting the guy in the suit touch the knob.

Notice the voltmeter in the upper right corner of that panel goes up to 2500V DC, and the lower right ammeter goes up to 2 Amps. That is enough power to do some damage, and to transmit a signal pretty far.

It's reasonable to assume that the motor-generator set makes the high voltage DC. There's likely to be a rather large transmitting tube behind the big panel.

No Master!


Tune for Minimum Smoke

In my early ham radio days vacuum tube equipment with its high voltage requirements was the rule. The ham joke when tuning a transmitter was to aim for minimum smoke. Tuning was the process of getting the maximum amount of power from the transmitter into the antenna for a given transmission frequency. The gent appears to be doing this. Having received a few minor pokes from equipment over the years, these old photos with exposed knife switches and fuse blocks still give me the willies.

Keep Off!

Not out, but "off." And in chalk, at that.


"Can't wait to play my Jolson records on this baby, oh mammy!"

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