Quad's story begins in 1936 in London, when engineer Peter J. Walker founded S.P. Fidelity Sound Systems, quickly renamed the Acoustical Manufacturing Company, initially producing public address equipment before turning attention to the home. The company relocated to Huntingdon, Cambridgeshire, in 1941, where it remains based today, and it was there that Walker's guiding philosophy — "the closest approach to the original sound" — became the engineering principle behind every product Quad has built since.

That philosophy produced a genuine string of hi-fi landmarks: the 1953 Quad II power amplifier, whose innovative cathode-coupled design achieved such vanishingly low distortion that it remained in production for 18 years, and the 1957 ESL — the world's first full-range electrostatic loudspeaker, using a massless film diaphragm to deliver a level of transparency and speed that conventional dynamic speakers still struggle to match. The achievement earned Quad the Queen's Award for Technological Achievement in 1978, followed by the acclaimed ESL 63 in 1981, whose patented concentric electrode design became a reference standard around the world.