by Norman Eisenberg
The Men Who Made an Industry: DAVID HAFLER
Thirteenth in a series.
JUST BEFORE THE U.S. entered World War II, David Hafler started a career as a statistician, having just graduated as a mathematics major from the University of Pennsylvania. His spare time was spent tinkering-one project involved trying to get a record player to play through a radio set. Hailer's interest was part musical and part mechanical: He had studied violin but never developed real proficiency at it, and he loved to modify things to see if he could make them work better.
This project was interrupted by a stretch of service in the Coast Guard, but not before he had picked up some valuable "nuts-and-bolts" electronic insights. As executive officer of a shorthanded vessel, he had to double as communications officer, which got him up to his elbows in high-grade equipment circuitry. He avidly read the manuals that explained how the gear worked and how to repair it.
At the war's end, Hailer headed back to his Philadelphia home, dusted off his radio-phono project, turned on the juice, and saw the whole rig promptly go up in smoke. He began to study in earnest-taking enough time out to earn his living in market re search-and read everything available on radio and electronics. He recalls that one of his main texts was the Radio Amateur's Handbook. Soon he began buying parts from radio suppliers around town and, guided by a schematic diagram, built his own set, even fashioning and punching the chassis.
He picked up a speaker, built a box for it, and hooked up the system. This time it worked.
Delighted, Hailer continued to make modifications, mainly following circuit diagrams published in such periodicals of the time as Radio News.
His amplifier then had a triode (three-element tube) output stage, and he had added his own feedback loop for reduced distortion. One day in the late 1940s a friend named Herb Keroes, an electrical engineer employed by a transformer company, took a look at the homemade sound setup. Keroes was impressed, and he suggested only that an output transformer of his own design be substituted for the one in the circuit. The swap was made, and both men were ecstatic over the improved sound-wider in range, more powerful, and with less distortion than either had heard before.
They soon began speculating about manufacturing amplifiers, but their plans did not crystallize until the fall of 1949, when the first big high fidelity show (then called the Audio Fair) took place in New York City. Hailer visited the display of Sun Radio, a large New York dealer, with the hope of selling output transformers for use with the amplifier kits that Sun had put on the market earlier that year. He found that Sun was getting its transformers from Peerless, which was present with its own display to demonstrate how good its transformer design was by running square-wave tests. Hailer offered to submit his own transformer to testing. It outperformed the Peer less model.
That did it. On the train home to Philadelphia, Hafler and Keroes decided to form their own company called Acro--to produce and market audio transformers. Essentially, Hafler's power amplifier circuit was built around the transformer, which was sold by promoting the idea of building one's own amp from circuit diagrams published by Acro.
An outstanding feature of the circuit was the "ultralinear" design (patented by Hailer) that, in a sense, combined the best aspects of the then two differing approaches to amplifier de sign: the lower distortion of the triode and the high power of the pentode. It also lowered output impedance for a better match with the speaker.
Eventually, Hailer proposed sup plying all the amplifier parts. Keroes demurred, but Hailer was adamant.
As a result, they severed their connection. Hafler sold his interest in Acro to his partner and, in 1955, launched Dynaco, the first full-time manufacturer devoted exclusively to high fidelity kits. Dynaco was unique in another way at that time: It was the first kit company to sell through regular high fidelity dealers. The first product was the Mark II (Mark I never got to the market), a 50 -watt mono power amp kit that retailed for $69.50. (It was also offered wired for $10 more.) The Mark II proved an astonishing success. Its cost-less than half that of comparably powerful conventional amplifiers-was the lowest per watt of any amp. It was built by legions of audio enthusiasts, got rave reviews in the press, and virtually set a new standard for home music systems.
Fortunately, too, for Dynaco, the acoustic-suspension speaker-introduced to the audio market in the early 1950s--responded beautifully to the high power and wideband response of the Mark II. This fact was not lost on Edgar Villchur ("Pathfinders," August), who saw the amp as a low-cost device that would help sell his AR speaker.
In 1957 Dynaco brought out a preamp that proved no less sensational than the power amp. At the time, Audiocraft magazine (a onetime sister publication of HIGH FIDELITY) said that the preamp's distortion was literally unmeasurable. According to Haller, the distortion (either harmonic or IM) actually was well under 0.1% throughout the normal audio band at any output level. And the unit used only two tubes for its circuitry. This preamp, too, can be said to have revised home standards considerably.
As stereo came into its own, Haller saw a chance to expand the company's product offerings and began importing pickups from the Danish firm of Bang & Olufsen. There were two versions of the "Stereodyne" as it was called-one was an integrated arm and cartridge, the other a cartridge alone. In the early 1960s Dynaco added the B&O open -reel tape deck to its line, but the relationship ended in 1968, when B&O decided to set up its own U.S. distribution.
By 1968, with a string of successful products behind him (which included the Dynaco tuner that first appeared in 1961), Haller decided to sell. He remained, however, as company head under contract for another three years. During this period Dynaco started importing loudspeaker systems built to its specifications by Scan-Speak, another Danish firm.
Haller patented (in his own name) the Quadaptor, by means of which out -of phase recorded signals in stereo or specially recorded material could he fed to back-channel speakers for a quad effect without an additional amplifier. When he left Dynaco in 1971.
Haller bought a half-interest in Ortofon, which this year became a part of Harman International.
Hafler, now fifty-seven, insists he always made products he wanted for himself. He believes that his success in high fidelity may have been compensation for not succeeding as a musician. A similar motivation, he feels, accounts for his tenacity in another field of interest. A chess player since his twelfth birthday. he has harbored a frustrated ambition to be a top ranking player or tournament-level contender. He has built up a collection of chess sets--now numbering about three hundred-that is reputed to be the finest in existence and has attracted visitors from all over the world.
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(High Fidelity, Jan. 1977)
Also see:
The Parallel Careers of Edison and Bell; James A. Drake; Geniuses in sometime contact--and conflict
New Equipment Reviews (Jan. 1977)