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Quad Electroacoustics is a British manufacturer of hi-fi equipment, based in Huntingdon, England. == Corporate history == 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. Peter Walker Quote December 1975 technical paper 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.’ Peter 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. (It’s a lot more difficult to achieve very low distortion in high powered amplifier stages). Peter 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. Peter Walker was also attributed with the famous hifi quote "the perfect amplifier is a straight wire with gain" --- 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. It was an aim, a goal, a description of the perfect amplifier - nobody, including Mr. Walker, ever said they'd attained that goal, and even if they did, the chances were that they were severely handicapped by their test equipment at the time. 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.〔(CHINA: Behind the scenes at IAG | whathifi.com )〕 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 International Audio Group under the management of Bernard and Michael Chang. Since Walker's death in 2003, the firm has had only its design ethos—"the closest approach to the original sound"—in common with the British hi-fi firm he founded in 1936.〔(Wharfedale Achromatic WA-S1 Speaker System | Home Theater )〕 In 2003, a book was commissioned "QUAD The Closest Approach" which offered a history of the company from its creation to that point. The company's founder, Peter J. Walker, died in 2003 at the age of 87. He had retired in the late 1980s, then turning management over to his son Ross Walker. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Quad Electroacoustics」の詳細全文を読む スポンサード リンク
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