If I remember correctly, Peter Walker of Quad fame once arranged a carefully constructed blind listening test between a tube amp and an ss amp. The panel was made from studio professionals and musicians. The conclusion was that no difference could be detected between two well-designed amplifiers regardless of the type (tube or ss), as long as the amplifiers were operated within their design parameters (i.e. not clipping).True, have any double blind tests between valve and solid state amps been conducted? I wonder how open those who believe in valves are to such tests (perhaps you need a selection of people who believe they can hear the difference, and prefer the perceived difference of valves over ss)