VOLUME 13 SEPTEMBER 1996 NUMBER 9
Collecting Foreign Sets(Web Version)
The Kenmac Book Crystal Set -- A Novelty Radio
BY IAN L. SANDERS
"The 'Kenmac Book' crystal set, though novel in design, loses nothing in efficiency by being so, as it embodies in its design certain features which are absolutely essential if good reception of the Broadcasting Coy.'s Programmes is to be heard by the 'Listener' with the clarity of tone which undoubtedly makes 'Listening-in' a real pleasure." (From the Kenmac Book crystal set instruction book)
The idea of the novelty radio as a sales gimmick is almost as old as broadcasting itself. Because of their constructional simplicity, crystal sets were a natural choice for this market, and, from the early 1920s on, manufacturers offered novelty crystal sets in various guises.
Such crystal sets were produced on both sides of the Atlantic. Models built around pottery designs, for example, are known from both U.S. and British manufacturers (e.g. the Brush Pottery Company's "Bug" crystal set and the Grafton China Works' "Uncle Tom" set). Another classic is the miniature crystal set produced by Radiax Limited of London in 1923, which was built into a standard matchbox of the day.
Novelty crystal sets were also occasionally offered as promotional items with the ubiquitous "Quaker Oats" model made by the Marquette Radio Corporation in the U. S. as a prime example. An innovative theme was the so-called "talking book" radio, doubtless playing on the idea that listening-in should be afforded the same respectability as was given to reading. This article describes one such set -- the Kenmac Book.
In addition, at least two U.S. makers and one other British manufacturer are known to have offered crystal sets disguised as books during the 1920s. Examples are the 1923 "Talking Book" crystal set, produced by the Listen-In Company of Boston, Massachusetts, and the 1925 Teletone Model C by the Teletone Corporation of America. In January 1921, Mitchell's of London advertised a primitive, but novel, crystal set called the "Wireless Pocket Book." Windings inside the covers acted as a variometer, with tuning effected by opening and closing the book.
THE KENMAC BOOK CRYSTAL SET
In mid-1925, at what was practically the end of the crystal set era in Great Britain, Kenmac Radio, Limited, of Hammersmith, West London, introduced its patented Kenmac Book crystal set. The receiver was in the form of a small book, measuring just 4 3/4" x 3 1/2" x 1", shown in Figure 1. It was produced in two styles -- an imitation tortoise-shell finish, and a less expensive model available in a red, green or blue leather "binding" with gilt-edged "pages." The tortoise-shell version was advertised, rather curiously, as non-inflammable. (One must suppose the number of instances of a crystal set actually igniting to be rather limited!).
The standard inscription imprinted on the front cover of both versions is "The LISTENER by E.R. Phone," with a more ornate typeface being used for the tortoise-shell model. Alternatively, the set could be supplied, "... at little or no extra cost," with any choice of personal customized lettering on the front cover. The base of the "spine" bears the company name -- Kenmac Radio Ltd.
Figure 1. The Kenmac Book crystal set was available in a leather-covered (left) or tortoise-shell (right) version.
The two styles are basically identical, except that a spiral spring is used to hold the cover closed on the leather-bound model, while a more robust latch is found with the tortoise-shell finish. A further minor difference is that the engraved tuning scale on the tortoise-shell case is replaced by an ivorine label attached to the inside of the leather-bound set. The leather-bound case version is shown in Figure 2.
Figure 2. The leather-bound version of the Kenmac crystal set has an ivorine tuning scale.
The Kenmac Book crystal set features slide-coil tuning with a linear tuning scale graduated between 0-100. The set covers the usual broadcast wave band, and a miniature double-socket on the spine enabled a long-wave loading coil, using a special pin supplied with the set, to be fitted for the reception of the BC's 5XX station. The detector is of the conventional galena/catwhisker type, but, due to the severe space constraint, the detector arm is somewhat shorter than usual, making adjustment cumbersome. All of the fittings are brass.
The general construction of the Kenmac crystal set was of high quality for the period, and the set received a very favorable review in the September 5, 1925, edition of the British magazine Popular Wireless and Wireless Review. The journal did not, however, completely approve of the standard wording on the front cover, described as quite artistic; nevertheless, it was noted that the customized lettering should "... prove useful at Christmas" and that demand would likely be considerable.
The only real criticism was the perceived need for insulation on the detector arm and on the tuning slide, in order to prevent accidental shorting of the headphone terminals. Otherwise, the Kenmac was described as a first-class receiver.
The price of the Kenmac book in 1925 was two pounds, two shillings (#2.10) for the tortoise-shell version and one pound, one shilling (#1.05) for the leather-bound edition.
The author is indebted to Pat Leggatt for supplying a copy of Popular Wireless magazine containing the report on the Kenmac receiver, and for pointing out the existence of the earlier book-type set produced by Mitchell's. Thanks also to Simon Wade for providing a copy of the original instructions supplied with the Kenmac book.
Bussey, Gordon. Vintage Crystal Sets. London: IPC Business Press Ltd., 1976.
Hill, Jonathan. Radio, Radio! Devon, England: Sunrise Press, 1986.
Popular Wireless and Wireless Review, Vol. 8, No. 171, September 5, 1925.
Radio News, October 1926, p. 443.
Sievers, Maurice L. Crystal Clear. New York: Vestal Press Ltd., 1991.
Stokes, John W. The Golden Age of Radio in the Home. New Zealand: Craigs - Printers and Publishers, 1986.
Wireless World, January 8, 1921.
(Ian L. Sanders, 16725 Wild Oak Way, Morgan Hill, CA 95037)
Ian Sanders has been collecting and restoring early 1920s crystal and battery receivers since 1974. He specializes in British sets of this period, and would be happy to try to answer any readers' inquiries on this subject.