Marshall Amplification is a British company that designs and manufactures music amplifiers, speaker cabinets, brands personal headphones and earphones, and, having acquired Natal Drums, drums and bongos. It was founded by drum shop owner and drummer Jim Marshall, and is now based in Bletchley, Milton Keynes, Buckinghamshire. Marshall's guitar amplifiers are among the most recognised in the world. Their signature sound, characterized by sizzling distortion and "crunch," was conceived by Marshall after guitarists, such as Pete Townshend, visited Marshall's drum shop complaining that the guitar amplifiers then on the market didn't have the right sound or enough volume. After gaining a lot of publicity, Marshall guitar amplifiers and loudspeaker cabinets were sought by guitarists for this new sound and increased volume. Many of the current and reissue Marshall guitar amplifiers continue to use vacuum tubes (also called valves in Britain and some other regions), as is common in this market sector. Marshall also manufactures less expensive solid-state, hybrid (vacuum tube and solid state) and modelling amplifiers.