Today we’ll look at several Turner microphones of the 1940s which were marketed to Radio Hams in the pages of QST.  The development and marketing of recording-studio microphones is generally oriented towards full frequency response, low self-noise, and the ability to handle large sound-pressure levels without distortion.  The development and marketing of live-sound, I.E., PA-system microphones places a definite emphasis on these points as well, but with an equally strong emphasis on durability and feedback rejection.  Ham, or ‘communications’ mics, on the other hand, have the unique distinction of being designed to emphasize the frequency range most necessary to intelligible human speech: approx 500hz to 5000hz.  This is done to ensure that the broadcast will only issue forth the necessary sonic information: the communication value of the words themselves.  Fidelity to the actual tone and timbre of the speaker, and/or the sonic representation of the speaker’s environment (IE the room he/she is in) are irrelevant for this activity.  So when you think about that ‘old mic’ sound, yeah, it is somewhat the result of primitive technology.  But it is also in-part an intentional, engineered condition.

The Turner Model 20X Microphone

The Turner Model 22 Microphone

The Turner Model 33 Microphone

The Turner Model VT73 Microphone.  This model of microphone was also manufactured with a built-in control knob to operate a wire recorder.  Not so different from the USB ‘podcasting’ mics of the 2010’s: combining the acoustic-pickup device with certain elements of the actual recording apparatus (I.E., the d/a convertor and mic preamp) into a single unit.

Above is the ARRL’s mission-statement as published in 1947. Anyhow, over the next few days I will post a few interesting bits from QST in the immediate post-WW2 era.  There was a tremendous surge in amateur radio activity at the time, owing to the return home of the servicemen who had learned radio-technology in the war.

These men had been given an introduction to radio and electronics in the most intense possible situation -the life-and-death struggle of global warfare – and it’s no surprise that this powerful link would fuel an intense post-war peacetime interest in Ham activity.

Above: a Tom-Of-Finland-esque advert for Solar Capacitors from a 1947 QST.

We’ll start today with a couple of interesting schematics for push-pull audio amps: a 6F6 15 watt push-pull amp, and a cathode-coupled 6L6 40 watt amp.  I have never used a 6F6.  Anyone?  And I don’t recall ever having seen a cathode-coupled push-pull driver circuit.  Check ’em out…

Tomorrow: Turner Ham mics of the 1940s.

Have you ever been driving around and noticed one of these huge metal antennae towers erected beside a home?

(image source)

These are Ham Radio towers.  ‘Ham Radio’ is non-commercial, amateur radio-broadcasting activity which has carried on for nearly a century all over the planet.  Although by definition both amateur and non-commercial, Ham Radio is regulated by the governments of the world (including the US) and a license is required in order to participate.  The plus side of the this regulation is that, unlike, say, C.B. radios, Ham Radios can be incredibly powerful and experienced operators can (with the right equipment) directly contact other like-minded enthusiasts all over the world.  This actually sounds a lot like something else we’re familiar with…  oh right the internet.

So much can be said about this venerable institution, and I am not person to do the explaining.  So why discuss it here?  Well… most common of the signals sent with Ham Radio has always been the human voice; many Hams have, and still do, carry on the tradition of designing and building their own audio equipment; and the innovations sprung from this field have played an important role in the development of audio technologies that we all use today.  The importance of the technical aspects of signal transmission/reception in the Ham community cannot be overstated; in fact, most of he conversations that go on using this technology are in fact concerning the signal quality itself.   A direct consequence of this importance of signal integrity is that Radio Hams would often send physical postcards, in the actual mail, to those individuals with whom they had chatted with on-air.  These postcards confirmed the technical operating parameters of the radio equipment in-place when the successful conversation took place.  These are called QSL cards, and they are one of the most fascinating and exciting examples of vernacular graphic design that I am aware of.    E.  purchased a crate of several hundred at the flea market yesterday; they all date from around 1980-1987 and they are really idiosyncratic and beautiful.  Here I will present some of my favorites:

Follow the link below to continue…

All of the cards pictured above were sent by male Ham operators.  These seems to be a vastly greater proportion of male Hams to female, but ladies (and couples!) are represented too….

The images you are seeing above are the forward-facing ‘picture’ sides of the postcards; the backsides contain technical details regarding the reception, as well as address information and often a personal note of some kind.  Here’s a look at the reverse of one card; this will give you a good sense of the kind of information that’s being exchanged.

*************

*******

***

Looking at this box of hundreds of cards, you can imagine the countless hours and years spent accumulating them; days spent fine-tuning equipment and searching the airwaves for another person to speak with briefly.  As you might imagine, these cards only ended up in my hands due to the passing of the man who had collected them.  In Ham Radio speak, a deceased operator is termed a ‘silent key,’ ‘key’ refers to a morse code input-key;  morse code being the first type of signal sent by radio waves well over a century ago.  So much of the antique vacuum-tube audio equipment that we modern audio DIY’ers encounter, purchase, and dissect in pursuit of our various projects comes from the radio-shacks of these silent keys; the legacy of men and women who harnessed primitive hardware to reach out across great spans and make contact with others.