In 1950 David Hafler and Herb Keroes started a Philadelphia-based company called Acrosound to build and sell audio-quality output transformers, primarily for home electronics hobbyists.

[1] 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.

[1] 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.

[1] 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.

[1] Hafler wrote an article for Radio-Electronics Magazine in 1955 delineating the design of a high-power version of the Williamson amplifier using ultra-linear circuitry and Dynaco's new output transformers.

In later years, the company began to produce a line of solid-state audio components, commencing in 1966 with the introduction of the Stereo 120 power amplifier (60 wpc).

Because of early problems involving circuit, power supply, and transistor failures, the ST 120 was not as popular as earlier Dynaco tube amplifiers.

Numerous small circuit changes were introduced by Dynaco over the years in an attempt to improve the stability and reliability of the ST 120, without much success.

This was a high power amplifier at 200 watts per channel that offered automatic protection circuitry to prevent electrical destruction of the loudspeaker.

[2] A modified aperiodic bass reflex design using SEAS speakers in a handsome wood cabinet, the A-25 sold for $79.95 each in 1969[3] making it competitive with much more expensive loudspeakers.

The patented aperiodic (essentially non-resonant) woofer design utilized a highly damped vent instead of a reflex port, whose acoustic resistance is very carefully controlled.

This "Dynaco patent" required a single resistor and a threeway potentiometer for the two rear speakers, generating phase difference signals for a feeling of ambience.

David Hafler remained with the company a few years longer, but left in 1974 to join Ortofon, manufacturer and importer of high-end phono cartridges.

The speakers were well regarded by the audiophile community, but their introduction was apparently too late to make any strong impression in the marketplace, and Ed Laurent left shortly afterward to join SEAS Corporation.

While Panor owns the Dynaco brand name and trademark, there is no longer any direct connection with the company founded by David Hafler.