For sale is an antique set of RADIOFONE headphones, left behind in the radio electronics "collection" of my late father, who was an active and avid HAM radio operator for over 70 years.  He was a US Army Radio School instructor during WWII, and was a radio and other electronics serviceman for much of his life.  He LOVED radio!

As we go through Dad's collection, my husband dives into research on line and through old magazines and catalogs, to see the history of these antique artifacts.  For this headset, we have learned SO much about early radio, and he wrote this up for you to enjoy.  And if you purchase the headphones, be sure to copy the history to "bring life" to share when you display your antique "treasure."  

DESCRIPTION: Own a piece of Crystal Radio history with this early 1920’s headset, trademarked “Royalfone King of All.” This exemplar of crystal headset technology is being sold for display or restoration. As an antique artifact, it belongs in a public or private museum! It could be yours! Engineered by Charles Lehrfeld, Navy radio instructor, and veteran of the Great War (WWI), Royalfones were developed between Marconi’s era of radiotelegraphy and the broadcast boom of late 1922. In the earliest days of his engineering venture, more than 13,500 U.S. radio amateurs were reapplying for station & operator licenses, which had expired during the U.S. wartime radio ban. That year (1920) Westinghouse Electric & Manufacturing Company had secured the first U.S. commercial broadcasting license from the U.S. Department of Commerce, Bureau of Navigation. In November, the 1920 Presidential election returns were announced over Westinghouse’s radio station KDKA in Pittsburgh. It was the first scheduled U.S. radio broadcast. By January, 1921, Montgomery Ward & Co., of Kansas City, Missouri & Chicago, Illinois, began advertising headsets. In February, C. Brandes, Inc. introduced high-impedance, Navy Type headsets for vacuum tube circuits. Later in 1921, Charles Lehrfeld, radio engineer, and entrepreneur Harry L. Denburg, organized Royal Electrical Laboratories of Newark, New Jersey. At the end of the year (1921) there were just 5 radio broadcast stations in the country, offering listeners their choice of grand opera, orchestras, phonograph music, press summaries, market reports, sermons and speeches. However, Lehrfeld was engineering his 16,000-turn headset, with 2200-Ω receivers, for use in WWI era radiotelegraphy. They were intended to “hear” long-distance signals, that often required a loud speaker. (Loud speakers of that time were two-foot gooseneck horns, with 14-inch diameter bells!) The first Royalfone model was released to market in the second quarter of 1922; along with at least a dozen other new headset brands! Headphones selling on the East coast suddenly swelled from 6 brands to 19; accompanied by at least 7 new radio magazines, which commenced publication between April and July, 1922. By August, Lehrfeld had engineered a new13,000-turn Royalfone headset, with 1500-Ω receivers. The artifact offered here is that historic headset – designed for use with crystal and bulb detectors! (The “bulb” was De Forest’s patented, vacuum tube triode, or Audion, which was substituted for the famous galena, lead-sulphide crystal at the heart of early crystal radios.) Guaranteed, 1500-Ω Royalfone headsets made their market debut, shoe-horned between pre-war, $12.00, 1200-Ω Baldwin sets and the new $5.00, 2000-Ω Murdock No. 56 headsets. The Royalfone now became the subject of a nation-wide advertising program.

By October, 1922, Royal Electrical Laboratories was warning its dealers and agents to “Be prepared to meet the demand for a crystal phone for a crystal set.” But, the era of modern radio was already overtaking crystal and bulb sets. E. H. Armstrong ushered in this new era with his Super- Regenerative Receiver; which was displayed on October 6, 1922, at the Newark Radio Show’s Dealer’s Night. Royal Electrical Laboratories’ Sales & Advertising Director, Harry L. Denburg, was a member of the Dealer’s Committee. The future was in sight! In December, 1922, Royal Electrical Laboratories exhibited their headsets at New York’s Grand Central Palace, during the American Radio Exposition. By year end (1922). there were 30 U.S. radio broadcast stations (a 6-fold increase over 1921); but, the broadcast boom was just starting! By January, 1923, rapid sales growth had forced Royal Electrical Laboratories to abandon its old South St. factory, relocating in a factory at 109-111 Tichenor St., Newark. The firm now had contracts with crystal radio manufacturers, to furnish headsets as standard equipment on their new detector sets. One such manufacturer was Newark’s Bershaw Radio & Manufacturing Co. Bershaw crystal radio sets featured a Grewol-brand crystal detector and this 1500-Ω Royalfone headset for a dealer’s net of $12.75. By now, Royal Electrical Laboratories distributed to U.S. & Canadian agencies, which sold only to jobbers and preferred dealers. Those agencies were situated in Minneapolis; Des Moines; St. Louis; Newport, Kentucky; Detroit; Dallas, Texas; Albany, New York; Collingswood, New Jersey; plus the Canadian Presener Sales Agency of Montreal and the Winnipeg agency of Moncrieff & Andreas, Ltd. Royal Electrical Laboratories was one of the founding members of the Radio Manufacturer’s Association of Newark, New Jersey; which formed on April 5, 1923. Harry L. Denburg was one of two Royal Electrical Laboratories employees who joined, serving as the association’s charter secretary. The other employee was A. O. Karsten. By year end, 1923, there were 576 broadcast radio stations in the United States – an increase of more than 18-fold over the previous year! The future had arrived! 

Driven by new super-heterodyne radio markets, Royal Electrical Laboratories expanded their product line, by December, 1923, with the development of “Royalfone” King of All loudspeaker units. By October, 1924, the surge of loudspeaker unit contracts, from makers of console radio sets, had forced the firm to take over the entire two-story factory at 109 Tichenor St. They expanded to 9,000 square feet; sheltering the whole sales and advertising team, which had previously been at the Market St. office. Royal Electrical Laboratories also had branches in Los Angeles, CA; Milwaukee, WI; St. Louis, MO; Pittsburgh, PA; Baltimore, MD; and Denver, CO. Royalfone King of All crystal headsets, meanwhile, were “listening in” worldwide, in Argentina, Canada, New Zealand, Cuba, Sweden, Mexico, Australia, and Tasmania. “Royalfone” King of All headsets continued to supply the crystal and tube detector radio market until second quarter of 1926, when a tragic fire resulted in $25,000 damage to the interior of their Tichenor St. factory. In its brief existence, Royal Electrical Laboratories took leading radio industry roles in the engineering, development, manufacturing and marketing of early radio products!

(For further background on Newark inventor, Charles Lehrfeld; and the Newark firm, Royal Electrical Laboratories, find more at the end of this listing!)

MANUFACTURER: Royal Electrical Laboratories of Newark, New Jersey (Manufacturers of Electric and Radio Equipment)

INVENTOR:  Charles Lehrfeld of Newark, New Jersey, who invented the Royalfone King of All headset during the years 1920-22.

REDESIGNING DOUBLE TELEPHONES: By the time the U.S. Navy entered WWI, in 1917, the standard for excellence in electro-magnetic receivers was the Baldwin double telephone, with its famous micanite diaphragms. Operators, however, complained that the Navy Type C Baldwin phones were too heavy.  They exceeded 24 ounces - the weight of Type E phones. Improved Type F Baldwin headsets reduced the burden from 24 oz. to a weighty 19 ounces.  The Century Telephone Construction Co., a Buffalo, New York subsidiary of the Federal Telephone and Telegraph Co., developed a lighter alternative.  The Century headset, in 1919, weighed only 13-½ ounces and featured cases of aluminum; which weighed less than Baldwin’s Bakelite cups. Instead of micanite, Century headsets used 0.012-inch thick silicon steel diaphragms.  By 1920, headsets with aluminum cases were also being featured in headsets by Red Head and Stromberg-Carlson.

LEHRFELD'S DESIGN:  As a U.S. Navy radio operator, Lehrfeld saw the trending headset improvements, as the bulky Type C set was replaced by 24 oz. and 19 oz. models; and, eclipsed by the 13-½ oz. Century set. Lehrfeld’s design weighed only 12 oz. Lehrfeld accomplished this by using aluminum cases, similar to Century; achieving further reductions (and greater sensitivity) by reducing the steel diaphragms from 0.012-inches to 0.007-inches thickness. Thinner diaphragms permitted the use of smaller magnetic fields to vibrate them. Thus, Lehrfeld was able to reduce the weight of the magnets; and, also the number of turns of magnet wire in the coils. The ability to wind thousands of turns of fine, magnet wire on headset coil forms was a limiting factor in the manufacture of contemporary phones. Thus, Lehrfeld’s design resulted in the reduction of weight, cost, and complexity of manufacture.

INVENTORY STATUS:  Pre-owned by my father. The arc of his radio career was similar to that of Charles Lehrfeld. Like Lehrfeld, my father became a radio enthusiast in his youth, receiving an amateur radio license at age 18. My Dad enlisted in the military to pursue his study of radio, as Charles Lehrfeld had, in the midst of a world war. When the United States subsequently entered WWII, Dad became a radio instructor for the U.S. Army Signal Corps radio school at Fort Monmouth, New Jersey. He rose to the level of Staff Sergeant and served at Fort Monmouth for the remainder of the War.

TRADEMARK:  “Royalfone,” King of All (U.S. Patent Office Serial 165,819, published in October, 1922.)

VINTAGE:  Antique, 1922-1926

CASES:  Appear to be cast aluminum.

EARPIECES:  Appear to be Bakelite or similar phenolic-based thermoset plastic.

DIAPHRAGM:   Features 0.007-inch thick steel diaphragm.

MAGNETS:  Designed with Tungsten steel.

POLE PIECES:  Designed with Norway iron.

FIELD COILS:  Designed with 13,000 to 16,000 turns.

CORDS:  Designed with five-foot cords, featuring different colored stripes for polarization, to guard against demagnetization from vacuum tube circuits. (This became a problem when detector sets evolved from the use of galena crystals to vacuum tube circuits, incorporating De Forest’s Audion “bulb.”)

PIN TIP PLUGS:  About 0.085-inch (2-mm) diameter pin plugs.

HEADBAND:  Dual spring-wire headband, which appears to be covered with tightly- woven cloth or canvas, with slip-bushings to provide adjustability to each receiver.

WEIGHT:  About 12 ounces

CONDITION:   As is — As found — As Photographed. This item is a pre-owned item; that may have dust, dirt, wear, dents, rust, oxidation, chips, scratches, etc. which can be from usage or age-related, environmental, or handling & storage effects. See photos. Buyer should review photos & the applicable texts before deciding to purchase this antique artifact. All electrical items are non-returnable. This headset is being sold as a collectible, antique artifact for display or restoration. Seller has no means of testing this device. Buyer accepts all responsibility for its use, & application to any electrical device or circuit.

WHO WANTS THIS?  Public and Private Museums ─ Collectors of Royalfones ─ Collectors of antique and vintage audio equipment ─ Radio Amateurs ─ Prop managers ─ Interior Decorators ─ Early radio headset collectors ─ Anyone in the radio communications industry ─ Historical Societies ─ Anyone in the headset or earphone manufacturing or retail sales industry ─ Collectors of antique, WWI period artifacts ─ Residents of Newark NJ ─ Descendants of Charles Lehrfeld or Harry L. Denburg ─ Anyone seeking a Christmas gift for someone who has everything except this treasure from radio history!

 A Narrative History of Royal Electrical Laboratories: About 1921, with the help of Newark businessman, Harry L. Denburg, Charles Lehrfeld formed the Royal Electrical Laboratories to manufacture and market his newly designed headset. On March 1, 1922, the headset was dubbed Royalfone King of All, which would become the firm’s trademark by October that year. When the first headset model appeared, in the second quarter of 1922, the fledgling enterprise occupied a small quarters at 179-191 South Street, in Newark, New Jersey. When a second model was introduced, in August that year, the sales and advertising staff, under Denburg, moved to 207 Market St. Denburg sought salesmen for exclusive terri-tories, and obtained contracts with the manufacturers of crystal and bulb detector radios. By November, a nation-wide advertising campaign was underway. With sales and advertising out, the whole South St. factory was devoted to production.

Royal Electrical Laboratories was an exhibitor at the December, 1922, American Radio Exposition, in New York City. Thanks to Denburg’s accumen, sales surged, and, in January, 1923, the South St. factory was abandoned. Lehrfeld moved the production operation into the first floor of 109-111 Tichenor St. Its exclusive customers consisted of jobbers and preferred dealers. Royal Electrical Laboratories became a charter member of the Radio Manufacturers Association of New Jersey, formed in April, 1923. By year end (1923), Royal Labs was advertising its new “Royalfone” King of All Loudspeaker, and Loudspeaker Unit, augmented by a new phonograph attachment. By September, 1924, another sales surge had forced the firm to occupy the entire Tichenor St. factory, expanding operations to the second floor, for a total of 9,000 square feet. The Market St. sales & advertising operation was also moved into the Tichenor St. factory. In July, 1925, Royal introduced a new product: the Royalfone Type 01A triode vacuum tube. The tube operated as a detector, audio amplifier or radio amplifier. In August, 1926, Popular Radio listed the firm’s headset, loudspeaker, and phonograph attachment on its tested list of “approved apparatus.” Sadly, Royal Electrical Laboratories was already out of  business. A tragic fire, in the second quarter of 1926, caused $25,000 damage to the interior of the Tichenor St. factory. The Royal Distributing Company, Newark, New Jersey became the successor firm.

Newark Inventor, Charles Lehrfeld: Charles Lehrfeld’s fascination with radio telegraphy began when he was about ten years old, and inspired his child-hood pursuit of amateur radio. When America entered the Great War (WWI), on April 7, 1917, Lehrfeld was already enlisted in the US Navy, and serving at the Newport Radio School in Rhode Island. There, his knowledge and experience with amateur radio had earned him a position as a radio instructor and operator. Soon, the U.S. Navy needed radiomen to manage ship communications aboard their new, SC-1 class sub-chasers; built and deployed to combat the German U-boat threat. Eventually, Lehrfeld was assigned to one of these 85-ton sub-chasers, and served as a radio officer in the Atlantic theater.  When his enlistment expired, circa 1920, Lehrfeld set out to develop a better head-set. As a U.S. Navy, radio operator and instructor, Lehrfeld had an opportunity to use state-of-the-art Brownlie & Baldwin, Type C, Navy headsets... and their successors. Users of early Navy radio head-sets complained that they were too heavy; lacked adjustment; didn’t fit all head sizes; created uncomfortable skull contacts with their metal parts; and, frequently snagged the operator’s hair in the headband.

For two years, Charles Lehrfeld labored to engineer a better headset for radiotelegraphy. By March 1st, 1922, the new 16,000-turn Royalfone headset, with 2200-Ω receivers, was dubbed “Royalfone” King of All. By June that year (1922) the Royalfone headsets were in production and advertised by radio industry magazines. Lehrfeld oversaw the factory and research operations at 179-191 South Street.

The emerging radio broadcast industry in the U.S. spurred Lehrfeld to design a headset better fitted to public demand for crystal or bulb detector sets. By August, 1922, Lehrfeld had engineered a new 13,000-turn Royalfone headset, with 1500-Ω receivers. Two months later, a nationally-advertised sales campaign was underway.

The advent of Armstrong’s Super-heterodyne Receiver created a new headache for telephone designers. They would have to accommodate voltage changes which occurred when the radio was switched from the detector to one or two stages of amplification. By January, 1923, Lehrfeld was working on a solution, engineering an adjustable diaphragm, which would regulate the air gap between the diaphragm and the poles. The adjustable diaphragm appeared on the telephone receiver in the new loudspeaker units, which Royal Electrical Laboratories released later that year. The loudspeaker unit had a special attachment for phonograph arms, for which a patent was requested in June, 1924. Patent No. 1,554,012 was awarded to Charles Lehrfeld, by the U.S. Patent office in September, 1925.

Wow!!  LOTS of information!!  I hope you enjoyed the history, not only of this antique headset, but of its role in early radio history!!  I hope you would love to have this to display in YOUR antique radio equipment collection!!

Thanks for looking here!!

(radio shelves)