#Dynaco pas 4 preamplifier driver#
#Dynaco pas 4 preamplifier Pc#

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). VI mono power amplifier of 1976, which produced 120 watts (continuous). The company's final contribution to vacuum tube technology was the massive Mk. Dynaco continued to build both mono and stereo amplifiers until 1977. Even today, upgraded components, rebuilding kits, and complete tube amplifiers using the basic Stereo 70 design are still in production, and the ST 70 has inspired numerous other amplifier designs, such as Ars-Sonum's Filarmonia SE. In 1992, an updated version of the Stereo 70, the Stereo 70 II, was produced by Sound Valves for Panor Corporation. ДЄ smaller tube amplifier, the 17.5wpc Stereo 35, was introduced in 1963, and was followed the next year by the SCA 35, the company's first integrated (preamp + power amp) tube amplifier. Because of its excellent value for cost, Dynaco tube amplifiers were often referred to as 'the poor man's McIntosh.' More than 350,000 ST-70 amplifiers had been sold when production finally ceased, making the ST 70 the most popular tube power amplifier ever made. The popularity of the ST 70 contributed more than any other single product to continuing consumer interest in tube-based stereo amplifiers at a time of increasing market dominance by solid state audio products. This design reduced distortion and improved audio quality.ДЄ masterpiece of efficient circuit design, the ST 70 provided reliable, high-quality audio amplification at an affordable price. The output transformers are an ultralinear design, whereby part of the primary winding is fed back to the output tube's screen grid.

#Dynaco pas 4 preamplifier driver#

The driver circuit had a single 7199 pentode/triode tube per channel, and used the driver tube to handle both voltage amplification and phase splitting. The ST 70 used four Eе…ѓ4 output tubes, one GZ34/5AR4 rectifier tube, two 7199 input (driver) tubes, two output transformers, one power transformer, and a preassembled printed circuit board (PCB) containing the driver circuit. Introduced in 1959, the ST 70 was available as a kit ( Dynakit) intended for assembly by the purchaser or as a complete factory-wired unit. Today, Dynaco is best remembered for its highly regarded vacuum tube stereo amplifier, the Stereo 70 ( ST 70). Shortly thereafter, the company moved its business operations to 3912 Powelton Avenue in Philadelphia, where they remained for several years. The Williamson amplifier utilized a slightly different circuit design from the Mk. 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. II was sold for several years until its replacement in 1956 by the Mk. Available as a kit or preassembled unit, the Mk. The company was incorporated in October 1955, with business premises located at 617 N. In 1955, the two men founded the Dyna Company (later Dynaco) with the intention of not only producing transformers, but high-quality audio circuitry. 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 1954 Dave Hafler and Herb Keroes parted company.

#Dynaco pas 4 preamplifier Pc#

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 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. The Acrosound transformer circuit was later used in many home-built and commercial hi-fi amplifiers in the early 1950s. The two men refined and developed the ultra-linear 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. 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.