Dynaco - Early Company History

Early Company History

In 1950, David Hafler and Herb Keroes started a Philadelphia-based company called Acrosound in order to build and sell audio-quality output transformers, primarily for home electronics hobbyists. The two men refined and developed the Ultralinear audio circuit pioneered by British audio electronics engineer Alan Blumlein, using taps from the output transformer to feed signal back into the output stage screen grid circuitry. The Acrosound transformer circuit was later used in many home-built and commercial hi-fi amplifiers in the early 1950s. In order to appeal to a wider consumer market, Hafler decided to design and build entire power amplifiers as build-it-yourself kits, complete with preassembled, tested circuit boards that only required the customer to wire the boards to the transformers, controls, and power supply to complete the project. This was a considerable advance over other audio system kits of the day, which generally required the purchaser to assemble and test the PC boards themselves, a relatively precise and time-consuming task.

In 1954, Dave Hafler and Herb Keroes parted company. During a visit to the New York-based Brociner Electronics the same year, Hafler met an audio engineer named Ed Laurent, who had designed a novel single-tube driver circuit for a power amplifier. In 1955, the two men founded the Dyna Company (later Dynaco) with the intention of not only producing transformers, but high-quality audio circuitry. The company was incorporated in October 1955, with business premises located at 617 N. 41st St in Philadelphia. Dynaco's first product was the Mk. II 50-watt power amplifier. Available as a kit or preassembled unit, the Mk. II was sold for several years until its replacement in the 1960s by the Mk. III amplifier, which produced 60 watts. Hafler wrote an article for Radio-Electronics Magazine in 1955 delineating the design of a high-power version of the Williamson amplifier using Ultralinear circuitry and Dynaco's new output transformers. The Williamson amplifier utilized a slightly different circuit design from the Mk. II and Mk. III. Shortly thereafter, the company moved its business operations to 3912 Powelton Avenue in Philadelphia, where they remained for several years.