Quad Electroacoustics, founded in 1936 by Peter J. Walker in London, is a British high-fidelity audio company renowned for pioneering electrostatic loudspeakers and innovative amplifier designs. The name “Quad” stands for “Quality Unit Amplifier Domestic,” reflecting the company’s commitment to superior sound reproduction. In 1957, Quad introduced the ESL-57, the world’s first full-range electrostatic loudspeaker, known for its clarity and low distortion. The company also developed the Quad II amplifier and the 33/303 pre/power amplifier combination, both celebrated for their performance and design. Today, Quad continues to produce high-quality audio equipment, including the ESL-2812/2912 electrostatic speakers and the Artera integrated amplifiers, maintaining its legacy of delivering exceptional sound quality.