 | |
| Company type | Private limited company |
|---|---|
| Industry | Home entertainment equipment manufacturing & distribution |
| Founded | 1936 |
| Headquarters | Huntingdon, England |
| Products | Hi-fi equipment |
| Parent | International Audio Group |
| Website | www.quad-hifi.co.uk |
QUAD Electroacoustics is a British manufacturer of hi-fi equipment, based Huntingdon, England. QUAD is part of the IAG Group, with corporate headquarters located in Shenzhen, China.
The company was founded by Peter J. Walker in 1936 in London, and was initially called S.P. Fidelity Sound Systems. In 1936 the name was changed to the Acoustical Manufacturing Co. Ltd. The company moved from London to Huntingdon in 1941 after being bombed out of London in World War II.
The company initially produced only public address equipment but after the war they began to produce equipment designed for use in the home as a result of the rising demand for high quality domestic sound reproduction. Within a few years the company had transitioned almost entirely to manufacturing models for the home audio market.
Walker was quoted in December 1975 in Wireless World magazine, "An audio power amplifier is required to produce an output signal that differs from the input signal in magnitude only. It must therefore have occurred to every circuit designer that it should be a simple matter to take a portion of the output, compare it with the input to derive an error signal. It is then only necessary to amplify the error signal and add it to the output in the correct amplitude and phase to cancel completely the distortion of the primary amplifier."[ citation needed ]
Walker put this principle into practice using two amplifiers per channel instead of one. The first stage error amplifier is low powered but very high quality. The second amplifier is high powered, but of lesser audio high quality. Walker designed a way to compare the high powered output with the original audio input and derive the required error correction signal which is then injected into the audio path, in such a way that the high power audio output achieves a very low distortion figure, even at very high power levels. This innovative product earned Quad the Queen's Award for Technological Achievement in 1978.
Walker was also attributed with the famous hifi quote "the perfect amplifier is a straight wire with gain" with the implication being that nothing would be added, and nothing taken away from the signal, just a bigger version of the same thing at one end.[ citation needed ]
The name "QUAD" is an acronym for "Quality Unit Amplifier Domestic", used to describe the QUAD I amplifier. In 1983, when having become known for their QUAD range of products, the Acoustical Manufacturing Co. Ltd changed its name to QUAD Electroacoustics Ltd.
In 1995, QUAD Electroacoustics Ltd was bought by Verity Group plc, joining its existing brands of Wharfedale and Mission. A few changes were made, including shifting all production to Shenzhen, China. [1]
In September 1997 the company changed ownership again as Verity Group sold off businesses to finance its development of flat panel loudspeakers. With Wharfedale it became part of the Chinese International Audio Group under the management of Bernard and Michael Chang.
In 2003, a book was commissioned "QUAD:The Closest Approach" which offered a history of the company from its creation to that point.
Peter Walker died in 2003 at the age of 87. He had retired in the late 1980s, turning management over to his son Ross Walker.
C25 integrated mono valve PA amplifier- 1941+
M31 integrated mono valve PA amplifier - 1946+
MB31 integrated mono valve PA amplifier - 1946+
M32 integrated mono valve PA amplifier - 1947+
MB32 integrated mono valve PA amplifier - 1947+
M60 integrated mono valve PA amplifier - 1947+
M18 integrated mono valve PA amplifier - 1952+
U112 combined integrated mono valve PA amplifier and mixer with 3 microphone inputs - 1945+
U113 combined integrated mono valve PA amplifier and radio tuner - 1945+
Source: Audio! Audio! [2]
The company's first major products were released in 1948. The QA12 and QA12/P were low-powered mono valve designs. This unit's sound quality reproduction was high compared with other products on the market at the time, and was thus adopted for use by the BBC. This valve power amplifier featured a cathode-coupled winding dating from 1943, which eventually became the Quad II. The QII preamplifier accompanied it. [3]
Following the mass production of 'stereo' vinyl records in 1958, the QC 22 control unit was developed and released in 1959. [3] This was a stereo control unit that was designed to be used with a pair of QUAD II mono power amplifiers. To complement the QUAD II, the company also produced AM and FM tuners for use with the QC II & 22 control units. [3]
The company made the transition to transistor-powered models in 1966 with the "professional" QUAD 50 monobloc which had a tapped transformer output, and in 1967 the consumer Quad 33 preamplifier and 303 stereo power amplifier combination.
Quad QC1 Control Unit - 1951 to 1953 - 2000 units [3]
Quad QCII Control Unit - 1953 to 1959 - 20,000 units [3]
Quad 22 Control Unit - 1959 to 1967 - 30,000 units [3]
Quad 33 – 1967 to 1982 – 120,000 units [3]
Quad 34 – 1982 to 1995 – 41,000 units [3]
Quad 44 – 1979 to 1989 – 40,000 units [3]
Quad 66 – 1986 to 1997 – 12,000 units [3]
Quad 99 - 1999 to at least 2003 [3]
Quad QC-twentyfour - 2000 to at least 2003 [3]
Quad 303 – 1967 to 1985 – 94,000 units [3]
Quad 77 - 1996 to 1999 - 2,500 units [3]
Quad 99 - 1999 to at least 2003 [3]
Quad I - 1951 to 1953 - 2,000 units [3]
Quad II - 1953 to 1970 - 90,000 units [3]
Quad 50E - 1966 to 1983 - 12,000 units [3]
Quad 99 - 2000 to at least 2003 [3]
Quad 405 – 1975 to 1982 – 64,000 units [3]
Quad 405–2 1982 to 1993 – 100,000 units [3]
Quad 306 – 1986 to 1995 – 25,000 units [3]
Quad 606 – 1986 to 1997 – 27,700 units [3]
Quad 707 - 1997 to 1999 - 4,500 units [3]
Quad 909 - 1999 to at least 2003 [3]
Quad 909 Mono - 1999 to at least 2003 [3]
Quad QA12/P - 1949 to 1951 - 1,000 units [3]
Quad 77 - 1994 to 1999 [3]
Quad 99 Stereo - 1999 to at least 2003 [3]
Quad 99 Mono - 2000 to at least 2003 [3]
Quad HR1 - 1949 to 1951 - 500 units [3]
Quad AM - 1954 to 1970 - 2,500 units [3]
Quad AMII - 1960 to 1969 - 10,000 units [3]
Quad AM3 = 1969 to 1973 - 2,000 units [3]
Quad FM - 1955 to 1967 - 25,000 units [3]
Quad FMII - 1968 to 1971 - 7,500 units- [3]
Quad FM3 - 1971 to 1982 - 50,000 units [3]
Quad FM4 - 1982 to 1995 - 37,000 units [3]
Quad 66FM - 1991 to 1996 - 5,100 units [3]
Quad 77FM - 1996 to 1999 - 1,500 unts [3]
Quad 99FM - 1991 to at least 2003 [3]
Quad FM Multiplex decoder - 1965 to 1967 - 5,000 units [3]
Quad 66 CD - 1989 to 1994 - 13,000 units [3]
Quad 67 CD - 1993 to 1996 - 6,100 units [3]
Quad 77 CD - 1996 to 1999 - 3,500 units [3]
Quad 99 CD - 1999 to at least 2003 [3]
In late 1949 (or early 1950), the company launched the CR corner ribbon loudspeaker. This used a Goodmans Axiom 150 cone loudspeaker for the lower frequencies and an electromagnetic ribbon loudspeaker, designed by Acoustical, for the higher frequencies. Fewer than one thousand units were sold.
In 1957, they released the Quad Electrostatic Loudspeaker (ESL), the first production full frequency range electrostatic loudspeaker renowned for sonic transparency and very low distortion. Its sonic neutrality and transparency were offset by its extreme directionality, moderate power handling, the need for a large room, and moderate bass extension; its novel electrical characteristics could render some amplifiers unstable, which could result in damage to either or both.
The ESL was quickly adopted by the BBC for monitoring the sound quality of their broadcasts. The BBC eventually replaced them with moving coil based monitor speakers developed by several manufacturers, such as the highly successful LS3/5A, that were more easily transported and stored, and were more representative of typical contemporary hi-fi speakers.
Quad launched ESL-63, successor to the original ESL, in 1981. The newer design featured larger panels and an innovative stator design, made up of eight concentric rings fed from the centre outwards through analogue delay lines, so that the audio signal radiated out as though emanating from a single point. Subsequent electrostatic models, the 988/989, the 2805/2905 and then the 2812/2912 were successive refinements of the ESL-63 design, featuring increased power handling and output levels, more sophisticated overload protection, and greater structural rigidity.
Following the Verity acquisition, Quad developed and market a range of conventional electrodynamic loudspeakers alongside its electrostatic line, available in both passive and active (i.e. featuring in-box amplification) configurations.
Many of Quad's products, including the Quad Electrostatic Loudspeaker (ESL-57), are still serviced by the company's Service Department in Huntingdon.
An audio power amplifier amplifies low-power electronic audio signals, such as the signal from a radio receiver or an electric guitar pickup, to a level that is high enough for driving loudspeakers or headphones. Audio power amplifiers are found in all manner of sound systems including sound reinforcement, public address, home audio systems and musical instrument amplifiers like guitar amplifiers. It is the final electronic stage in a typical audio playback chain before the signal is sent to the loudspeakers.
An audiophile is a person who is enthusiastic about high-fidelity sound reproduction. An audiophile seeks to reproduce recorded music to achieve high sound quality, typically in a quiet listening space and in a room with good acoustics.
An electrostatic loudspeaker (ESL) is a loudspeaker design in which sound is generated by the force exerted on a membrane suspended in an electrostatic field.
Monaural sound or monophonic sound is sound intended to be heard as if it were emanating from one position. This contrasts with stereophonic sound or stereo, which uses two separate audio channels to reproduce sound from two microphones on the right and left side, which is reproduced with two separate loudspeakers to give a sense of the direction of sound sources. In mono, only one loudspeaker is necessary, but, when played through multiple loudspeakers or headphones, identical signals are fed to each speaker, resulting in the perception of one-channel sound "imaging" in one sonic space between the speakers. Monaural recordings, like stereo ones, typically use multiple microphones fed into multiple channels on a recording console, but each channel is "panned" to the center. In the final stage, the various center-panned signal paths are usually mixed down to two identical tracks, which, because they are identical, are perceived upon playback as representing a single unified signal at a single place in the soundstage. In some cases, multitrack sources are mixed to a one-track tape, thus becoming one signal. In the mastering stage, particularly in the days of mono records, the one- or two-track mono master tape was then transferred to a one-track lathe used to produce a master disc intended to be used in the pressing of a monophonic record. Today, however, monaural recordings are usually mastered to be played on stereo and multi-track formats, yet retain their center-panned mono soundstage characteristics.
The Williamson amplifier is a four-stage, push-pull, Class A triode-output valve audio power amplifier designed by D. T. N. Williamson during World War II. The original circuit, published in 1947 and addressed to the worldwide do it yourself community, set the standard of high fidelity sound reproduction and served as a benchmark or reference amplifier design throughout the 1950s. The original circuit was copied by hundreds of thousands amateurs worldwide. It was an absolute favourite on the DIY scene of the 1950s, and in the beginning of the decade also dominated British and North American markets for factory-assembled amplifiers.
PS Audio is an American company specializing in high-fidelity audio components equipment for audiophiles and the sound recording industry. It currently produces audio amplifiers, preamplifiers, power related products, digital-to-analog converters, streaming audio, music management software and cables.
Harman Kardon is a division of US-based Harman International Industries, an independent subsidiary of Samsung Electronics. Harman Kardon was originally founded in Westbury, New York, in 1953 by business partners Sidney Harman and Bernard Kardon.
Founded by David Hafler and Ed Laurent in Philadelphia, Pennsylvania in 1955, Dynaco was an American hi-fi 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 loudspeakers. Dynaco was liquidated in 1980, and the trademark is now owned by Radial Engineering Ltd.
Robert W. (Bob) Carver is an American designer of audio equipment based in the Pacific Northwest.
Roksan is a British manufacturer of high fidelity audio products for domestic use, based in Rayleigh, Essex. It is best known for its influential and innovative design for hi-fi equipment, and in particular its Xerxes platform for playing LP records.
Multiple electronic amplifiers can be connected such that they drive a single floating load (bridge) or a single common load (parallel), to increase the amount of power available in different situations. This is commonly encountered in audio applications.
LEAK is the brand name for high-fidelity audio equipment made by H. J. Leak & Co. Ltd, of London, England. The company was founded in 1934 by Harold Joseph Leak and was sold to the Rank Organisation in January 1969. During the 1950s and 1960s, the company produced high-quality amplifiers, radio tuners, loudspeakers, pickups, tonearms and a turntable. The sale of the business to Rank saw an expanded range of models, and considerable further development of loudspeakers, but Rank was not able to position the brand to counter competition from Japanese electronics manufacturers, so by the late 1970s, electronics and speaker production ceased under the LEAK name.
A valve audio amplifier (UK) or vacuum tube audio amplifier (US) is a valve amplifier used for sound reinforcement, sound recording and reproduction.
Radford Electronics is a British audio manufacturer from Bristol, founded by Arthur Hedley Radford (G6YA) in 1946. Radford's hi-fi amplifiers enjoyed a reputation for quality that was "second to none", especially because of their output transformers.
Technical specifications and detailed information on the valve audio amplifier, including its development history.
The Braun LE1, Loudspeaker Unit 1, was the first electrostatic mode loudspeaker available on the German hi-fi market. German electronics company Braun started production in 1960 with the technology licensed from the British Acoustical Manufacturing Co. Ltd..
Home audio refer to audio consumer electronics designed for home entertainment, such as integrated systems like shelf stereos, as well as individual components like loudspeakers and surround sound receivers.
The Naim NAIT is an integrated amplifier from the British hi-fi manufacturer, Naim Audio. The original NAIT is one of the most recognisable pieces of hi-fi equipment ever made. Hi-fi critic Lucio Cadeddu recognised its legendary status, referring to it as "one of the most controversial and famous integrated amps in the history of HiFi".
The NAD 3020 is a stereo integrated amplifier by NAD Electronics, considered to be one of the most important components in the history of high fidelity audio. Launched in 1978, this highly affordable product delivered a good quality sound, which acquired a reputation as an audiophile amplifier of exceptional value. By 1998, the NAD 3020 had become the most well known and best-selling audio amplifier in history.
The Quad Electrostatic Loudspeaker (ESL) is the world's first production full-range electrostatic loudspeaker, launched in 1957 by Quad Electroacoustics, then known as the Acoustical Manufacturing Co. Ltd. The speaker is shaped somewhat like a home electric radiator curved slightly on the vertical axis. They are widely admired for their clarity and precision, but known to be difficult speakers to run and maintain.
