210:, 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.
225:) 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 1956 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
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ambience. The system worked best when the stereo sound had been recorded via two bidirectional microphones on the same spot. When microphone set-up changed to the use of multiple directional microphones and multitrack tape recording and postprocessing (i.c. in the CD era), the QD-1 was less effective.
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Concurrent with A-25 production, Dynaco introduced the QD-1 speaker adapter which synthesized 4-channel sound from the stereo amplifier output. This "Dynaco patent" required a single resistor and a threeway potentiometer for the two rear speakers, generating phase difference signals for a feeling of
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design using SEAS speakers in a handsome wood cabinet, the A-25 sold for $ 79.95 each in 1969 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
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products (and Dynaco's own vacuum tube kits) because of their preassembled circuit boards. These boards were wired at the factory, tested and packaged with the unassembled chassis. It remained only for the consumer to attach the switches and controls to the chassis pieces, assemble the chassis and
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A masterpiece of efficient circuit design, the ST 70 provided reliable, high-quality audio amplification at an affordable price. 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
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pentode/triode tube per channel and used the driver tube to handle both voltage amplification and phase splitting. The output transformers are an ultralinear design, whereby part of the primary winding is fed back to the output tube's screen grid. This design reduced distortion and improved audio
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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
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audio system manufacturer popular in the 1960s and 1970s for its wide range of affordable, yet high quality audio components.. Its best known product was the ST-70 tube stereo amplifier. They also manufactured other tube and solid state amplifiers, preamplifiers, radio tuners and bookshelf
302:, was produced by Sound Valves for Panor Corporation. 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
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remained with the company a few years longer, but left in 1974 to join
Ortofon, manufacturer and importer of high-end phono cartridges. In 1977, Hafler founded the Hafler Company, continuing the tradition of high quality but inexpensive kits and assembled hi-fi gear.
443:) acquired the Dynaco trademark, and in 1993 began marketing electronic audio components with the Dynaco brand. Panor introduced some new products, such as the Stereo 70 II. Panor/Dynaco's most ambitious stereo tube amplifier was the
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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.
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is very carefully controlled. The resistant venting action lowered the "Q" of the system and reduced impedance variation near resonance in the A-Series speakers. Dynaco followed the A-25 with the slightly larger
385:, which featured a dual-chambered, non-vented design in a walnut-veneered cabinet with even greater transparency and fidelity. Over time, Dynaco marketed a wide range of loudspeakers, ranging from the small
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was developed and marketed. This was a high power amplifier at 200 watts per channel that offered automatic protection circuitry to prevent electrical destruction of the loudspeaker. The
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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
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287:." 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.
369:, using input from Dynaco's David Hafler and SEAS's Ragnar Lian. The A-Series were marketed between from 1970 until Dynaco's demise in the 1980s. The
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dominance by solid state audio products. Because of its excellent value for cost, Dynaco tube amplifiers were often referred to as "the poor man's
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in 1979; the Dynaco division was closed in 1980 and its assets acquired by Stereo Cost
Cutters (later called Sound Values and Sound Valves).
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While Panor owns the Dynaco brand name and trademark, there is no longer any direct connection with the company founded by David Hafler.
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to build and sell audio-quality output transformers, primarily for home electronics hobbyists. The two men refined and developed the
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In later years, the company began to produce a line of solid-state audio components, commencing in 1966 with the introduction of the
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preamplifier in 1967, the company affirmed its ability to design reliable solid state equipment at an affordable price. In 1969 the
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power supply, and solder connecting wires to the circuit boards. This saved considerable time and reduced error in assembly.
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447:, a 75 wpc, all-tube stereo power amplifier with switchable pentode/triode modes, adjustable tube bias potentiometers, and
420:. Critical reviews of the new audio speakers were not favorable, and they disappeared from the market in the mid-1980s.
298:, the company's first integrated (preamp + power amp) tube amplifier. In 1992, an updated version of the Stereo 70, the
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integrated amplifier in the early 1970s time line. Dynaco's solid-state kits were different from the popular
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loudspeakers. Dynaco was liquidated in 1980, and the trademark is now owned by Radial
Engineering Ltd.
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In the late 1970s, Dynaco released a short-lived set of new loudspeakers developed by Ed
Laurent, the
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model proved to be extremely successful, selling between 600,000 and 1,000,000 units. A modified
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series. After some 30 years, these loudspeakers still command good prices in markets such as
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Today, Dynaco is best remembered for its highly regarded vacuum tube stereo amplifier, the
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In 1954 Dave Hafler and Herb Keroes parted company. During a visit to the New York-based
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Pictures, schematics, specifications and more of a large number of Dynaco products
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In 1950 David Hafler and Herb Keroes started a
Philadelphia-based company called
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The company's final contribution to vacuum tube technology was the massive
306:. Dynaco continued to build both mono and stereo amplifiers until 1977.
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using ultra-linear circuitry and Dynaco's new output transformers. The
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mono power amplifier of 1976, which produced 120 watts (continuous).
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Dynaco became a wholly owned subsidiary of Tyco, Inc. in 1969.
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US $ 79.95 in 1969 is equivalent to $ 468 in 2011 U.S. dollars
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audio circuit pioneered by
British audio electronics engineer
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reliability of the ST 120, without much success. With the
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270:(PCB) containing the driver circuit. It produced 35
466:, tuners, and preamplifiers between 1955 and 1976.
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57:. Unsourced material may be challenged and removed.
884:Defunct electronics companies of the United States
849:Audio equipment manufacturers of the United States
262:tube, two 7199 input (driver) tubes, two output
274:per channel. The driver circuit had a single
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869:Electronics companies disestablished in 1980
397:, and are a testimonial to their quality.
333:system was introduced, helping to start the
266:, one power transformer, and a preassembled
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854:Electronics companies established in 1955
117:Learn how and when to remove this message
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879:1980 disestablishments in Pennsylvania
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55:adding citations to reliable sources
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768:"Dynaco Speaker Component Info"
337:sound craze. In the 1970s, the
42:needs additional citations for
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844:Audio amplifier manufacturers
345:tuner was offered as was the
859:Electronic kit manufacturers
389:model to the floor standing
258:output tubes, one GZ34/5AR4
163:David Hafler and Ed Laurent
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824:- Dynakit official website
365:that were manufactured in
179:Philadelphia, Pennsylvania
864:Loudspeaker manufacturers
147:Audio system manufacturer
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811:Dynaco official website
361:'A-Series' of bookshelf
757:retrieved 8 August 2011
428:Dynaco was acquired by
828:Nostalgic Kits Central
822:http://www.dynakit.com
809:http://www.dynaco.com-
746:Dynaco Company History
437:Pan Orient Corporation
609:Dynaco Stereo 35
541:Dynaco Stereo 70
464:tube audio amplifiers
458:Dynaco tube equipment
418:Canton, Massachusetts
268:printed circuit board
194:Early company history
227:Williamson amplifier
215:Brociner Electronics
51:improve this article
18:Brociner Electronics
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815:2021-02-01 at the
753:2011-07-23 at the
462:Dynaco introduced
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776:. Retrieved
772:the original
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559:Dynaco PAS-2
507:Dynaco PAM-1
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107:January 2024
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49:Please help
44:verification
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645:Dynaco FM-3
636:(17.5 wpc)
618:(17.5 wpc)
593:Dynaco FM-1
584:(40 watts)
532:(60 watts)
498:(50 watts)
378:bass reflex
371:Dynaco A-25
279:quality.
169:Founded by
838:Categories
778:2014-08-29
696:References
681:Power Amp
613:Power Amp
579:Power Amp
545:Power Amp
527:Power Amp
493:Power Amp
445:Stereo 160
339:Stereo 400
329:4-channel
318:Stereo 120
231:Williamson
175:Ed Laurent
77:newspapers
649:FM tuner
597:FM tuner
550:(35 wpc)
414:Phase III
375:aperiodic
292:Stereo 35
260:rectifier
244:Stereo 70
200:Acrosound
181:in 1955,
813:Archived
751:Archived
480:(Power)
478:Channels
351:Heathkit
327:Dynaquad
285:McIntosh
238:Products
66:"Dynaco"
668:Stereo
665:Preamp
652:Stereo
566:Stereo
563:Preamp
511:Preamp
439:(later
367:Denmark
252:Dynakit
221:(later
160:Founder
152:Founded
91:scholar
634:Stereo
616:Stereo
548:Stereo
472:Model
347:SCA-80
311:Mk. VI
296:SCA 35
223:Dynaco
183:Dynaco
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600:Mono
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553:1959
535:1957
517:1957
514:Mono
501:1955
475:Type
323:PAT-4
272:watts
248:ST 70
187:hi-fi
98:JSTOR
84:books
684:Mono
582:Mono
530:Mono
496:Mono
449:6550
395:eBay
391:A-50
387:A-10
383:A-35
359:SEAS
343:FM-5
276:7199
256:EL34
173:and
155:1955
70:news
177:in
53:by
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