Sixty years ago, the August 1957 issue of Popular Electronics carried an article about the forgotten stepchild of audio recording: The 16 RPM record. More precisely, the records played at 16-2/3 revolutions per minute, and most moderately priced phonographs in the 1960’s would play the speed, along with the more common 33, 45, and 78 RPM speeds.

The 1957 article predicted, erroneously it turns out, that “the growing catalog of recorded material and new playback equipment in all price ranges proclaim that the tide may yet turn to 16 rpm and roll into the arena with quite a splash.”

A few musical recordings were issued on 16 RPM. Most notably, some records were produced for the benefit of Chrysler’s Hiway Hi-Fi experiment, which included a record player for the car. But the article noted that the speed, while longer playing, had inherently lower fidelity than higher speeds. At the time, the maximum frequency response went only to about 9000 Hz. The format was used mostly for “talking books.” The best seller was probably the Bible, which was recorded in the early 1950’s at the lower speed. If you search eBay today for 16 RPM records, the most common search result is this talking Bible.

As a kid, my record player had the setting for 16 RPM. Eventually, curiosity got the better of me, and I checked out a 16 RPM talking book from the library, just so that I could play it at home.

The article does include an interesting adapter, shown here. While the mechanical details are not explained, it allows a 16 RPM record to be played on a 33 RPM turntable. Presumably, it is powered by the spinning 33 RPM platter, and gears this down to 16 RPM for the record placed on top.

Maybe your MP3 player sounds a bit better than this gentleman’s hi-fi turntable from 60 years ago, but I bet you can’t build yours from scratch, like this guy did.  This one, shown on the cover of the 1957 edition of Radio-TV Experimenter, is entirely homemade, and despite the homemade appearance, probably did sound as good or better than anything on the market at the time, and would probably have sounded good even by today’s standards.

It was actually a phono oscillator, and transmitted the signal through an FM transmitter.  Since the audio quality of the FM signal was better than the recording technology of the day, the fidelity was limited only by the quality of the record.

Sound quality was paramount in every detail.  As is plainly visible, the tone arm is indeed made out of wood.  In particular, the wood is basswood, chosen because it had less mechanical resonance than other woods.  Metal would have been inferior, because of the capacitive effect with the leads running through it.

The pickup was homemade, not as a cost-saving measure, but because the design shown here was superior to the ceramic cartridges then commercially available.  It used a capacitive pickup.  The only commercial component was the sapphire-tiped needle, which was pushed into a rubber plug.  A copper plate was carefully positioned next to the needle to complete the capacitive pickup.

The tone arm was cut with a jigsaw, and the article contained precise instructions for balancing it.

The electronics, probably the easiest part to construct, consisted of a small FM transmitter employing a single 6C4 tube.  The example shown here was to be used for 45 RPM records, but the article noted that by adjusting the size and using an appropriate needle, it could be built for 33 or 78 RPM records.

Seventy years ago this month, the March 1947 issue of Popular Science showed how to put together this portable radio phonograph.  It was by no means deluxe, but it was the epitome of portability.  The magazine noted that in most cases, the “portable” terminology meant only that a handle had been slapped onto the cabinet, and the set was still tethered by the need for electrical current.   But in this case, a crank-up phonograph motor and a one-tube battery powered amplifier meant that it was truly portable.

The electronics consisted of a 1D8GT tube powered by two batteries, a 1.5 volt cell for the filaments, and two 67.5 volt batteries providing 135 volts B+, although it noted that it would work with as little as 90 volts.

The magazine noted that the spring motor should be set to 80, which would result in it running at the desired 78 RPM with a record on the platter.

The radio was simply a crystal set with a fixed crystal, which could be switched in place of the phonograph’s pickup cartridge.  While the radio strength was not great, it would serve to pull in local stations, especially with an external antenna and ground of some sort.

Seventy-five years ago this month, the March 1942 issue of Popular Mechanics carried a construction article for this portable phonograph oscillator.  Mounted in the always available cigar box, the one-tube record player used a 117L7-GT tube to produce a signal that could be tuned in on any nearby radio.

The tone arm could be removed when not in use, and plugged in with two phone tip plugs to hold it in place and make the electrical connection.

Since the phono oscillator only required one tube, and didn’t need an expensive speaker or transformer, they were quite popular for playing records for those who already had a radio.

For use right next to the radio, no external antenna was required.  For a bit more range, a short piece of wire could be added.  The coil inside was wound on a one-inch piece of cardboard, and a variable condenser could be tuned to a blank spot on the dial.