This is another in a continuing series of retrospectives remembering some of my favorite vintage analog radios.

Above: The Royal 400 in all 4 color combinations

Between 1955 and 1964 Zenith marketed the highly acclaimed Royal 500 series of radios. They were designated as “Pocket Portables” although they would require a coat pocket to fit, being much larger than “Shirt Pocket” portables. Nevertheless, the 500’s packed a powerful punch and, as with so many other innovative products, helped Zenith earn their reputation as a leader in technological development and overall quality. But the Royal 500 series commanded premium prices for their day and as competition from low-priced Japanese imports heated up Zenith had to offer lower priced models to remain competitive. And offer them they did with several models selling for less than the 500’s.

Above: Another lower priced model, the Royal 285 in three colors

This time we’ll look at a radio which represented the same concept and size as the Royal 500 series but at a lower price – the Royal 400. There were several others of this same size and general design, including the Royal 250, 265, 275, 280, 285 and 300 and they were generally good performers – in fact the Royal 285 contained the identical chassis as the Royal 500E-1.

Left: Royal 500H – Right: Royal 400

However, the Royal 400 is interesting because of all Zenith’s lower priced radios it is in some ways the closest in overall performance to the 500H. When introduced in 1961 the Royal 500H retailed for $59.95 while the Royal 400 was only $39.95 which translates to a $192 difference in 2022 dollars. To be sure, Zenith offered other models near this price point, so why do I consider the 400 to be unusually interesting? Primarily because the biggest innovation of the 500H compared with all of the previous 500 series was the introduction of Zenith’s unique 3” x 5” elliptical extended range speaker. This speaker claimed to have “no resonance” (which may or may not be possible but we don’t need to go there) and also utilized a new ceramic magnet which was much stronger for its size. Zenith’s ads proclaimed this speaker as the breakthrough in sound for their 500H and truly it was innovative, yet this same speaker was also used in the Royal 400 albeit with less fanfare. No other Zenith had this speaker.

Above: Royal 400 Interior

But weren’t there were cost-cutting compromises in the Royal 400? Yes absolutely, but they were cleverly chosen in such a way as to minimally impact performance under most conditions. In fact, when one actually compares the Royal 500H and Royal 400 side by side the differences are somewhat less than you would expect from the specs alone.

The first difference is the most obvious and that is the elimination of the untuned RF stage in the 400. This extra gain stage gives the 500H the edge when listening to very weak signals…signals at the threshold of intelligibility. These stations will be a bit quieter on the 400 next to the 500. Also, under some conditions a very faint signal may be more easily separated from surrounding signals on the 500H. But with more normal strength signals…ones you might actually want to listen to… you will be hard-pressed to detect much difference, meaning typical reception seems very similar. In today’s typically higher noise home environments you may not be able to detect much difference at all, but if you are in a very low noise environment and enjoy band scanning for very weak DX signals you will appreciate the higher RF gain of the 500H.

The second difference is the amplifier power. Zenith specifies the Royal 500 at 200 mw “undistorted” output and 340 mw max, while the 400 is rated at 100 and 180 mw. And although the schematics for the two radios reveal that they have virtually the same output amplifier design…even the identical output transistors operating at the same circuit voltages, there are differences (most likely the driver and output transformers) which account for the different specifications. I was skeptical but I verified the difference on the test bench…although the two amplifier circuits look pretty much the same, I measured higher audio output before clipping on the 500H just as Zenith’s specs indicate. However, I’ve got to say that the two radios sound pretty similar when I compare them side by side. You have to drive them to extreme volume to notice the difference. Because of that innovative speaker the Royal 500H and Royal 400 sound markedly better than any of the other Zenith radios of this size and the differences between the 500H and 400 are fairly subtle.

On a purely subjective note, I find the Royal 400 to be a very attractive design and I like it’s front-mounted vernier tuning knob. Both the 500H and 400 are very nice looking radios.

Conclusion: Zenith’s advertising was extensive for the Royal 500H and there’s no doubt that the entire 500 series was iconic and helped Zenith continue its tradition of quality and innovation. They are very much prized by collectors, and the Royal 500H is considered by many to be the pinnacle of the 500 series, but the little brother Royal 400 is a sleeper and is also an excellent radio in its own right so I want to give it its due…it’s one of my favorites from Zenith.

Jay Allen