Peter J. Walker (19162003), founder of Quad Electroacoustics and designer of some of the most well-regarded products in the history of domestic audio, famously believed that a properly designed audio-frequency amplifier should have no sound of its own. As for suggestions that his
Quad II amplifier (19531971) sounded better than most, Walker was unmoved: "We designed our valve amplifier, manufactured it, put it on the market and never actually listened to it."