The Royal 500H

In 1961, the Royal 500 went through a total redesign to it’s cabinet and chassis. The result was a new and completely re-engineered 500 H. This 500 (Model H) is the choice of collectors who value rich, clear, undistorted strong sound from their pocket radio. This is made possible with a large new oval extended range speaker and a redesigned chassis. The audio output of the 500H was increased from 100 to 200 milliwatts, and it’s overall performance set a new standard for all pocket transistors. The vernier tuner has gear reduced action and is very sensitive to pick up those tough stations (even those that are very close to one another).

The cabinets were offered in black, white, and a scarcer two-tone blue/grey. Zenith still used the more expensive “unbreakable” nylon material for the cabinet, but the material was very thin at the edges of the front and back halves, so many have chipped from use. All that said, I still agree with most collectors that state if you are looking for one transistor radio that you want to use and listen to, the Zenith Royal 500H is the one to have.

During a visit to Florida, I had the good fortune to be invited to the home of Norman Smith and saw his amazing Zenith collection. He told me the story about how he obtained his first transistor radio, a black 500H which he still plays every day.  He also told me several stories about how he has compared it’s performance with almost any other kind of transistor you can imagine, and his opinion still remains that this is the one to own. Good enough for me.
White Royal 500H Fact Sheet

Model: Royal 500H
Colors: Black, White, two-tone grey
Year introduced: 1961
Cost New: $59.95
Size: 5 1/2 x 3 1/2 x 1 1/2
Weight: 17.7 ounces
# of transistors: 8
Power: 4 AA batteries
Undistorted output: 200 milliwatts

Check out these Royal 500H radios.

Black Royal 500H
White Royal 500H
Two-Tone Grey Royal 500H
Another Black 500H
The 500H – Colors They Should Have Made

NOTE: In 1963, Zenith offered the 500E and 500H in an economy model. These were called the 500E-1 and the 500H-1. Many cost reductions were incorporated into these look alikes, but they made it possible to price these more competitively at $39.95, but the quality did suffer. They were made of plastic instead of nylon and finding one of these sets in excellent condition is not easy as they did not hold up as well as the originals. There rarity could also be because they were produced in limited numbers.

15 thoughts on “The Royal 500H”

  1. Great collection of Radios!! My aunt(has passed) bought a zenith 500 in 1960.I would visit her as a boy and spend all evening listening to that radio! Boy,was it a thrill!! She passed away in 1993 and I now own the radio.It stands with some of my other radios in the living room.Getting some history about these old sets is great! As it happens I work in radio broadcasting as an “engineer”. One of our stations is a 5,ooo watt Am derectional located on 1590.(Wakr). I /we have some vintage radio equipment at the transmitter site.Wakr went on the air in 1940. Anyway,thanks again !! Al.

    1. I do LOVE my Zenith Royal 500H! I bought it in 1962, to replace my RCA Victor 8B41 four-tube portable, and the two sets have very similar performance. But the RCA eats batteries (as all tube portables did), and more that seven decades of use have weakened its tubes somewhat. Both sets lack a tuned RF stage, so your beloved WAKR also will show-up at 680kcs. The Zenith 500H is indeed the finest “pocket” sized transistor radio ever made, and, despite a smallish ferrite core antenna, both its selectivity and selectivity hold their own very well against even the better large-sized portables: the dial is loaded with stations in the middle of the day. The 500H has weaknesses. It is over-designed to the point where even one component changing in value over time with cause it to become unstable and go into oscillation. Only about one-third of otherwise fine examples found in estate-sales actually work properly, if at all. Unlike earlier Royal 550 models, the battery-pack is mounted to the circuit-board and not to the cabinet. Drop it once, and you will spend countless hours looking for the microscopic cracks in the circuit-traces. The volume control is another problem: it becomes intermittent over time and use. If you want sound ALMOST as good, sensitivity just as excellent, are not as fussy about selectivity, and want long-term reliability, you might want to look at the Zenith Royal 500E, which preceded it. Another set, which offers you more reliability, almost comparable sensitivity, not-so-good selectivity, and similar tone with less audio power, if you can find one without a cracked or broken cabinet, go for the Zenith Royal 400, which was one model down from the 500H. Cheers!

      1. I have to apologise for the several typos in my February post, which I did not catch until now. I meant, selectivity and sensitivity, for one. I still have that 1949 RCA Victor Model 8B41, and it still functions well. But it is highly impractical to operate, owing to the scarcity and expense of the 67-1/2 volt “B” battery. To me, the most common Zenith Royal 500H, the one with the black cabinet, is still the most handsome, as the combination of jet-black high gloss contrasting with gold has a rich look which the white or two-tone grey versions cannot approach. The earlier (1961) examples had a smooth steel speaker-grill, finished in various shades of gold, from pale to almost copper, and these were more durable than the later sparkle-textured gold-anodised aluminium, which mine has; however, those steel grilles were prone to develop rust and/or corrosion spots — and many have become quite unsightly over time. The cosmetics of these radios did not hold up well when they were handled a lot — especially if the owner/user had acid perspiration. They were beautiful when New, but the same cannot be said for well-used examples found almost sixty years later. But, how many transistor portables will pick up a distant station on 1530 kcs. whilst standing within 100 feet of the towers of a 50,000-watt station on 1540 kcs.? There IS a problem, however, as anyone who has tried operating a Zenith Royal 500H in North Bergen, New Jersey, can attest. You see, all of the metropolitan New York “blow-torch” stations are right in the marshes around North Bergen — and when you have several 50-kilowatt powerhouses on A.M. all around you, the Royal 500H acts bewildered and has distorted images all over the place. But go three miles away, and things return to normal. The 1961 Royal 500H sets have the smooth speaker-grille (steel) and lack the designation, “DeLuxe”. The “DeLuxe” wording was added late in 1961, and the textured aluminium grille came soon after. There also was a change to the I.F. transformer cans, in 1962 — the earlier ones have a metal guard around them. The code-date stamped into the tuning-condenser is misleading, however, since it is the date that the part was made and not the date when it was installed into the radio. My 1962 example none-the-less has a 1961 code-date on the tuning-condenser. I would speculate that the actual date the radio left the factory is somewhere around six months after the date on the tuning-condenser. Does that help anyone? Examples of the Royal 500H vary quite a bit in performance and tone-quality, one to another, I have found. But the same can be said for almost any model of transistor radio. These were mass-produced, and “good enough” was usually good enough. You can get better sensitivity than what the Royal 500H will give you, in some larger portables — the limiting factor being the smallish loopstick antenna. Nevertheless, being able to walk around an area west of Binghamton, New York at midday, and still hear the larger New York City stations in local-reception clarity on a pocket radio is a treat! One more detail: earlier examples of this radio had a piece of black dial-string to remove the batteries, and dry-rot often causes these to break. Later in 1961, a clear thin flexible plastic was used, and that design retained throughout the rest of production. It has remained as durable as the day it was made. The dial-string version is highly vulnerable also to battery-leakage, to which the plastic version is virtually impervious. Battery-leakage, by the way, appears to have harmed a great number of these radios with both contact-corrosion and erosion of the paper on the inside-back of the cabinet — as well as sometimes the black cloth over the vents. Is this “too much information”?

        1. This is all good stuff Harrison. I find it to be very insightful and accurate with my findings, but you put it into words much better than I. Thanks so much. Gary

  2. Glad you enjoyed the site Al. Thanks for sharing your story. Many of my contacts have had similar memories of these great radios. Let them live on.

  3. One comment regarding the 500H. The one unique feature in the electronic design of this particular model was the addition of a twin IF filter between the mixer and first IF amplifier. All other similar models including the 280 series and other 500’s (that I have seen) had a single L-C filter at this location. This additional filter gave the 500H better selectivity than all other 500 models before and after. For some reason it was never used in other models. Cost? You can see these filters as the two metal cans to the right of the tuning cap and beneath the one inch long mounting stud for the back cover.

    1. Hello again! One design aspect of the 500H deserves note. It appears to have one local oscillator transformer, and five I.F. transformers. But this is NOT the case, and for a very important reason. Beginning with the 500-D “long distance” model in 1958, Zenith added an [untuned] R.F. amplifier stage, which greatly increased the sensitivity of the radio. The previous “500” models had the typical 3 I.F. transformers — but don’t kid yourself: because of the precision and hi-Q design, these sets (even the 1955-early 1956 hand-wired versions) had astounding selectivity; in fact, this “tight” tuning was difficult on the early asts without vernier tuning! But the 500H had high I.F. gain and 4 I.F. “cans”. As most of us know, the I.F. sections of radios tend to radiate R.F.: you will finf a “dead” carrier 455 kcs. above the frequency to which you are tuned, within short range of the radio. The 455kcs. I.F. amplification also radiates WITHIN the radio itself and is re-received by the internal ferrite antenna, creating a feed-back loop. To a degree, this aids both in sensitivity and selectivity — but, should the internal signal feed back too strongly, the radio becomes rife with gain-noise and even can go into oscillation. Add an untuned stage of R.F. amplification — and you make the problem far worse! And Zenith solved this situation with a tuned 455 kcs. transformer ahead of the I.F. stages, to bleed the 455 kcs. feed-back artifacts off to ground, after they have been amplified through the R.F. stage. Some technicians, not understanding this feature, instinctively tune all 455 kcs. transformers for maximum — then they wonder why they have high gain-noise with their selectivity, and their 500H breaking into oscillation below @ 700 kcs.: the PROBLEM is, that FIRST transformer needs to be set for MINIMUM, so it is bleeding the maximum amount of 455 kcs. reaching it, to ground. The more accurately that this is done, the lowest gain-noise you will have, as well as fewer “artifacts” at 910 kcs. And 1360/1370 kcs. (second and third harmonics, respectively, of 455 kcs.). The sound of the radio will be much cleaner and clearer. Now, before I leave you, I have a modification to improve the sound even more, IF your particular 500H is capable of the expanded audio-bandwidth (the speakers and audio-transformers in these sets vary in capability at the frequency-extremes). C-2 (a bypass to ground of 50 mfd.) can be increased to 1000 mfd., extending the bass. The radio will instantly sound warmer, richer, and a bit louder — and some of these radios also will go well below 100 c.p.s. — though at lesser volune than at mid-frequencies. Since these radios give a bright and lean crisp audio presentation, the added richness and warnth are welcome. But the added bass might tax the audio section — so listen closely — if there is a hint of distortion in the bass, then back-off to 500 mfd. or less. With patience, you will establish a value for that electrolytic condenser which works ideally for your 500H. Now, here is the final touch. Zenith put a .22 bright yellow-orange tubular condenser across the audio-output (easily seen near the bottom of the circuit-board); this was designed to soften hiss on weak stations and remove the 10 kcs. adjacent channel heterodyne “whistle”. But, in 1961, A.M. stations were severely restricted aboce 5,000 c.p.s., to minimise adjacent-channel interference — and so, filtering-out the top octave made sense when this radio was made. But relaxation of F.C.C. restrictions now allows high quality audio on A.M. with high frequencies never heard on A.M. in 1961. And so, as your final “mod”, remove this high frequency filter condenser from the circuit — and the clarity will open right-up, revealing F.M.-like sweetness on stations with the best in “processing”. Once you have made these two modifications, you will find you 500H transformed from a “big” sounding, room-filling “pocket” radio, into a “high fidelity” set which sounds several times its size, and is MUCH “cleaner” than even large portables such as the General Electric “Superadio”. The latter might produce a “juke-box” bass-quantity — but your Zenith will sound MUCH clearer, and will be even more joyful for both listening and DX-ing. Try the “graveyard” channels (1230, 1240, 1340, 1400, 1450, or 1490) — and you enter a new world of discerning individual stations within the jumbled bedlam on these frequencies at night! The 500H, because of its size, cannot be the “last word” in absolute sensitivity — but it isn’t too far from the best, either. Add a Select-A-Tenna for improved signal-gain — and you’re “off-to-the-races”, easily holding your own against any portable out there! One minor caviat on the audio-mod: Your battery-life will be about 90% of what it had been — because your audio-circuit is using a bit more “juice” (part of this will simply be your enjoyment of the notably “larger” sound). And others nearby will notice and wonder how you get such a rich and large presentation out of such a small set.????

  4. Another point about the 500H. There are two versions of the front oval speaker grille. One has a flat surface with punched holes and the other has a fabric weave-like texture. I do not know which came first or when the factory made the change.

    By the way, I have restored three 500H models; one of each color.


  5. Still another point about the 500H. There was a lot of hype when the 500H came out regarding its exclusive, patented oval speaker with the offset voice coil and ceramic magnet assembly. In reality, the only reason this design was used was that it was the only way to put a speaker in the chassis so that the magnet would clear the tuning capacitor at the top and the plastic battery holder at the bottom. I worked at Jensen in the late 70’s as an acoustical engineer and the company made millions of 6×9 and other size oval speakers for automobiles. For being so “radical,” neither Jensen or any other speaker manufacturer at the time ever considered using an offset magnet because of acoustical performance and manufacturing problems (the patent had expired by then). By the way, the speaker is mounted at an angle inside the case and does not line up with the oval grille on the front so part of the cone is blocked by the case.

    1. So little of the cone is “blocked”, that it makes no acoustic difference (unless you can HEAR the artifacts of some minor portion of the sound being routed AROUND the rim of the oval opening (which I doubt). As for the offset design: an oval speaker does spread-out cone-resonance over a RANGE of frequencies, especially at small sizes — avoiding that “squawky” quality that small round speakers have. RCA Victor knew this and incorporated a tiny oval speaker design into their “compact” portable tube sets in the 1940s. As for the off-set magnet, it gives a larger cone surface and lower frequency-resinance in one direction, adding some of the benefits of a larger speaker. With a 3″×5″ unit, the effect could be significant; however, with a 6″×9″, it might not be. The ceramic magnet gave better flux than the former alnico types (which were much smaller and far easier to accommodate). Designing an audio driver for an automobile is an entirely different proposition — since the “cabinet” is effectively the entire interior space of the trunk, allowing for trendous leeway in exciting the acoustic spaces involved; whereas, attenpting to gain “big” sound from a tiny portable radio is another matter completely!

  6. Gary, I love your site…very informative. Also, The items I bought were exactly as described and packed/shipped very well, and quickly. Quick question on the 500H. Why do some say Deluxe and others don’t? Are the ones W/O the H-1? How do you date the 500H? Thanks, CJ

    1. I am glad you approve and are happy with your purchase CJ. These are great questions. The very first of the 500H’s in 1961 were not Deluxe. These also had smooth grills. Soon after, they put the Deluxe badge on the grill and added a textured or “sparkle” grill variation. The 500H has a sequential serial number on the left side of the battery box which helps to date them (such as A803361), but there is also a date code at the bottom of the tuning capacitor (such as 6116 which means week 16 of 1961). The 500H was produced thru 1962 and perhaps past that, but the 500H-1 is another animal and it was supposed to have been produced in 1964, but try to find one. Very rare for some reason. They look the same on the outside but different chassis layout makes them easy to identify once inside. Hope that helps, Gary

      1. Hi, John! I left a reply for you once before, but I do not see it now. In regard to the oval speaker and your experience at Jensen: I respectfully disagree with your judgment that it was all about available real estate inside of the radio and not about acoustics. Space WAS a problem, especially with the introduction of the larger and stronger ceramic magnet replacing the prior alnico. The sacrifice there ended up being that the battery-case was mounted to the printed circuit-board in the 500H, as opposed to being fixed firmly to the cabinet itself as in previous “500” models. The large speaker-magnet left the circuit-board very narrow on either side — and so, if the radio were dropped, the weight of the batteries torquing against the narrow circuit-board sides on impact would cause the circuit-board to crack, breaking vital traces and connexions — requiring tedious soldering repairs which tended not to last very well in subsequent use. Tip: a micro-drop of superglue on the crack at the NON-print face of the circuit-board will greatly strengthen it again, and make the repairs to the broken circuits more endurable. As to the speaker-issue: comparing a 6×9″ automobile speaker with a 3×5″ pocket radio speaker is an “apples and oranges” argument. As you certainly know, John, bass-extension in a speaker-driver is a function of two main things: the diameter and suspension-flexibility of its cone on one hand, and its enclosure on the other. Your Jenson 6×9 used the entire air-space of the car’s trunk to establish efficiency in the low bass; moreover, it had much more radiating area, and thus ability to move air needed for bass-response, than a 3×5. A 3×5, mind you, which had to provide some lower frequency authority whilst operating cramped in a tiny cabinet! So, every minute advantage looms huge in that instance! The off-centre magnet/coil structure did two things: gave one dimension of the cone the bass-extension of a 4×6, and breaking-up the resonance-point by spreading it out over a relatively wide frequency band, eliminating that abrasive “squawky” tone of a small speaker in a small space. This is nothing new: RCA Victor, in smaller 1940s tube portables, used a little 1-1/2×3 oval speaker to accomplish that same thing — didn’t offer much in the way of bass, but wasn’t squawky or tinny, either! I am sure, if you found a comparable standard-design 3×5, and could A/B test against the strange Zenith design, you would hear the subtle inprovement Zenith had made here with working toward rich and full-blooded sound in a cramped space. One listen to the 500H demonstrates the success of their efforts. Myself having made a near-lifetime of “tweaking” and modifying “factory”-issue items for improved performance, I hold an especial respect for a manufacturer that works toward getting more performance out of a given product, than ordinarily would be possible. Zenith were able to add a high-gain untuned R.F. amplifier to the Royal 500H, because they also added a 455kcs. bleed-off adjustment to prevent feedback radiating from the I.F. section to the close-by ferrite antenna, from becoming re-amplified into the I.F. input, creating oscillation and excessive I.F. “images”. If you want to enjoy even BETTER sound, I recommend two circuit-changes (one not likely possible in 1961, and the other of no advantage back then). Remove the 50mfd. C-2 electrolytic condenser, and replace it with a 1,000 mfd. electrolytic unit — this wilk extend and warm the bass. There also is a rather large yellowish tubular .22 condenser across the output to remove the 10kcs. interchannel heterodyne whine endemic with A.M. radios back in the day when the F.C.C. restricted them to a 5 kcs. bandwidth and 100% modulation. If you remove this condenser (mounted along the bottom edge of the print side of the board), you will achieve near-F.M. quality sound on those stations transmitting broadband audio — and, for the added crystal-clarity, and non-closed-in trebel, I will TAKE the 10kcs. “whine” (I am in the eight decade range of life, so 10 kcs. might not trouble me as much as it might you — so TRY this — see if you like it — and if you don’t, put that high-cut bypass back in.

Leave a Reply

Your email address will not be published. Required fields are marked *