fi manufacturer . for the music project see quad music . quad electroacoustics limited type private limited company industry home entertainment equipment manufacturing & distribution founded 1936 headquarters huntingdon cambridgeshire 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 in huntingdon england . contents 1 corporate history 2 audio products 2.1 amplification 2.2 loudspeakers 3 references 4 external links corporate history edit 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 . 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 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 . 2 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 . audio products edit the company s first 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 . amplification edit quad 33 pre amp quad ii power amplifier following the mass production of stereo vinyl records in 1958 the qc 22 control unit was developed and released in 1959 . 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 . the company made the transition to transistor powered models in 1966 with the professional quad 50 monoblock which had a tapped transformer output and in 1967 the consumer quad 33 preamplifier and 303 stereo power amplifier combination . control unit pre amplifiers quad 33 1967 to 1982 120 000 units quad 34 1982 to 1995 41 000 units quad 44 1979 to 1989 40 000 units quad 66 1986 to 1997 12 000 units quad 99 1999 to 2002 stereo power amplifier quad 303 1967 to 1985 94 000 current dumping power amplifiers quad 405 1975 to 1982 64 000 units quad 405 2 1982 to 1993 100 000 units quad 306 1986 to 1995 25 000 units quad 606 1986 to 1997 27 700 units quad 707 1997 to 1999 quad 909 1999 to 2002 integrated amplifier quad 77 1994 to 1999 loudspeakers edit quad electrostatic speaker 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 and then the 2805 2905 were successive refinements of the esl 63 design featuring increased power handling and output levels more sophisticated overload protection and greater structural rigidity . a quad l ite satellite speaker provides the audio for a concert at home . 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 . all of quad s products including the esl57 are still serviced by the company s service department in huntingdon . references edit china behind the scenes at iag whathifi.com wharfedale achromatic wa s1 speaker system home theater external links edit official website http www.iaggroup.com http www.iaggroup.com quad1.html http www.iaggroup.com wharfedle.html retrieved from https en.wikipedia.org w index.php title quad electroacoustics & oldid 723134677 categories audio amplifier manufacturersaudio equipment manufacturerscompact disc player manufacturersloudspeaker manufacturerselectronics companies of the united kingdomelectronics companies established in 19361936 establishments in englandhidden categories engvarb from november 2013use dmy dates from november 2013 navigation menu personal tools not logged intalkcontributionscreate accountlog in namespaces article talk variants views read edit view history more search navigation main pagecontentsfeatured contentcurrent eventsrandom articledonate to wikipediawikipedia store interaction helpabout wikipediacommunity portalrecent changescontact page tools what links hererelated changesupload filespecial pagespermanent linkpage informationwikidata itemcite this page print export create a bookdownload as pdfprintable version in other projects wikimedia commons languages deutschfran aisnederlands svenskat rk e edit links this page was last modified on 1 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