Antique Radio Classified
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The Zenith Royal 500 Series



Pocket-sized transistorized radios were produced in great quantities by countless manufacturers, but Zenith's Royal 500 models seem to be the standout radios. (Editor)

Why do so many of us collect Zenith transistor radios? They weren't the first transistor radio or even the second or third. The Regency TR-1 was the first transistor radio, appearing in December 1954, six years after the transistor was invented and about two years after the wide acceptance of solid-state hearing aids. The Raytheon 8TP-1 came next in early 1955, followed by RCA, Philco, G.E. and, in Japan, Sony. Not until late November 1955 did Zenith introduce its first, the Royal 500, shown in Figure 1. The other American players soon followed in 1956 -- Motorola, Magnavox, Westinghouse and Sylvania.

Several factors made the Zenith 500 the star of the show, then and today. The power, tone and fidelity of this coat-pocket, purse-sized radio beat anything of its size, and the sensitivity and selectivity were better than even the larger tube portables. The beautiful styling and the glossy nylon cabinet of this $75 set spoke of the quality within.

Royal 500 pocket-sized transistorized radios
Figure 1. This radio was the first in a series of Royal 500 pocket-sized transistorized radios using hand-wired circuitry. It was produced from November 1955 to October 1956.

The Competition

During the first three years, Zenith really split from the other makers by introducing even more expensive radios -- the 800 at $89.50, the 750 at $79.95, the 950 at $150 -- as well as vernier tuning, IF amps, and other extra circuits, and special speakers. All of these added to the quality of the product.

Zenith essentially ignored the price competition from Japan during a period when other U.S. manufacturers were quitting the business or quickly cutting prices and quality. Zenith didn't make a radio under $30 until 1960 with the Royal 50, its first shirt-pocket model. Look through a Bunis transistor radio guide to understand how remarkable that is. We can trace Zenith's ride through the storm of cheap imports by examining the Royal 500 lineage.

version with redesigned knobs
Figure 3. Production of about 5,000 units of this version with redesigned knobs began in late 1956. As an aid to identification, the author has designated it as "500 AB."

The Royal 500 Lineage

Zenith produced several versions of the Royal 500. To distinguish the difference in these versions, I have added the "A," "AB," and "B" to the Royal 500 models, even though Zenith never used such a suffix until the "D," "E," and "H" models. Collectors have long referred to the change to printed circuit 500 from hand-wired chassis as the "B" model, so I'm not too far out of line. An example of the hand-wired chassis is shown in Figure 2 (see print version).

500B series
Figure 4. In 1957, Zenith switched from hand-wiring to printed circuit board construction on this 500B series with its white station indicator on the tuning knob collar.

About 100,000 Royal 500 units in black and maroon were made from November 1955 though October 1956. Until about Serial 18,000, the maroon cabinets were translucent. The chassis was hand-wired on an aluminum chassis sporting socketed transistors from Sylvania (chassis 7XT40), Raytheon (7XT40Z) or Texas Instruments (7XT40Z1). These radios are identified by the thin knobs with a long pointer bar across the face. The price was $75.

Next came about 5,000 Royal 500AB units built in late 1956, shown in Figure 3. These sets were still hand-wired on the metal chassis but have vernier tuning and thick knobs. They can be identified by the thin black station indicator on the tuning knob collar. The chassis is the 7XT40Z1. The white cabinets made their first appearance in this group. These 500AB radios appear sporadically from Serial 90,000 through 130,000.

Zenith made about 200,000 Royal 500B radios using printed circuit boards in 1957. Around Serial 180,000 the colors pink and beige were added. The 500B is identified by the thick knobs, vernier tuning and the wide white station indicator on the tuning knob collar. An example of this radio is shown in Figure 4. These first three models have significant overlap in serial numbers between 90,000 and 130,000 (Sept. - Nov. 1956).

In late 1957, Zenith added a wideband RF amplifier to the 7-transistor circuit to make the 8-transistor Royal 500, which I have given the suffix "D." About 250,000 of these were made in black, maroon, or white. This radio, shown in Figure 5, was a hot performer and fully warranted the "Long Distance" engraving on its face. The price remained at $75.

a 'Long Distance' radio
Figure 5. In 1957, a wideband RF amplifier was added to the 500D, making it an 8-transistor radio. It was labeled a "Long Distance" radio.

For easy comparison a close-up of the dials for the models 500A, 500AB, 500B, and 500D is shown in Figure 6 (see print version).

The 500D was given a major face-lift for 1959 and renamed the 500E. The circuitry remained essentially the same. A two-tone brick red and white was added to the black, maroon or white choice. An example is shown in Figure 7. Perhaps another 200,000 of these were sold, first at the (by then) extravagant price of $75, but most at $59.95.

the 500E
Figure 7. The next version in the series was the 500E, which usually sold for $59.95.

In 1961, Zenith pulled out all the stops in both circuit engineering and cabinet design to produce the Royal 500H, shown in Figure 8. What resulted was both sophisticated and beautiful. This is the one you should have for AM listening -- it is difficult even in 2008 to find a better performing portable AM radio. The color choice was ebony, ivory, or a two-tone blue/gray. Zenith made perhaps 250,000 of these and sold them at $59.95 up through 1964 at a time that you could buy a transistor radio at the local Five and Dime for $9.95!

End of an Era

The 500H marked the end of an era for Zenith -- the culmination of many design changes over the years. Figure 9 (see print version) shows versions A, AB, B, D, E, and H. The company could no longer afford to ignore the price competition and started buying parts overseas. Finally, it began moving assembly overseas also.

The Japanese makers, Sony, Panasonic, Toshiba, and others assumed the lead in quality, innovation, and sales for the bulk of the transistor radio market. However, Zenith earned high praise for continuing the very high quality Trans-Oceanic line through the 1970s with the hand-wired, American-made chassis.

the redesigned 500H
Figure 8. In 1961, Zenith produced its final version, the redesigned 500H with its oval speaker.

Estimates on production quantities are problematic after 1957 because the basic 6-digit system used for the 500s was shared by the Royal 300, 700, 750 and others. Zenith soon adopted several parallel numbering systems, beginning with A, T, X, and Z.

My numbers come from an analysis of how frequently they appear on eBay auctions. Any of these 500s can be found daily on eBay for $50 to $500, depending on condition and accessories. The mint 500H and the low-serial numbered (under 10,000) 500A command the highest prices. The lowest numbers to surface thus far are 00046, 00491, 00506, 00557 and 01683. If you find a low serial number in your collection, e-mail me with the data.

Now, get out there and buy one of these radios and start listening!


Bunis, Marty and Sue. Collector's Guide to Transistor Radios. Paducah, Ky.: Collector Books, 1996.

Lane, David & Robert. Transistor Radios, A Collector's Encyclopedia and Price Guide. Radnor, Pa.: Wallace-Homestead Book Co., 1994.

Mcgarra M. & Ball, Gary. Web sites.

Schiffer, Michael B. The Portable Radio in American Life. Tucson, Ariz.: University of Arizona Press, 1991.

Smith, Norman. Transistor Radios: 1954-1968. Atglen, Pa.: Schiffer Publishing Ltd., 1998.

------. Zenith Transistor Radios, Evolution of a Classic. Atglen, Pa.: Schiffer Publishing Ltd.,1998.

After 25 years of teaching in Key West, Florida, Phil MacArthur and his wife June happily retired and returned to the "four-seasons Northeast." ("And while we were gone, you guys invented the snow blower.") They collect Zenith radios and Flavoradios (who knows why).

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