The thing I’ve found is that it’s the valves themselves that have a dramatic effect on how the music through a Valve Amp sounds. It’s really interesting to play with various makes of preamp tubes to see what difference they make. Still available ‘New Old Stock’ examples are best. Siemens and Telefunken sound very neutral and clear, these approach SS amps in this but without losing the ‘liquid’ midrange. Mazda will give you more bass and Mullard are very warm and euphonic without sounding woolly or in any way muffled. What this means is that you can fine tune the sound to match the genre you’re listening to.