by JimN » 16 Aug 2014, 11:44
Valves do last well if not electrically abused. Just think of all those family radios, radiograms, record-players and TV sets, which would routinely operate for years without much attention (well, maybe the TV would need the occasional tweek or sharp slap in the right spot).
Blues and rock, with substantial overload of both the pre-amp and power stage valves (particularly on a small-ish amp), can soon cause sufficient wear for clean performance to be diminished. Contrarily, though, that can make the owner of the amp even more satisfied with its sound.
For me, and I suspect for you, the "proper" sound of any amplifier - including a Marshall or similar - is clean. Distortion is an effect which many players don't want anyway, but should be selectable if desired (depending on the circuitry of the amp).
Many players, though - especially some of those who profess to "demonstrate" guitars and amps on internet videos - seem incapable of playing anything with a clean sound and regard distortion as the natural sound of just about anything. Worn valves must sound great to them. I've even heard some players insist that a new amp doesn't start sounding good until it's been operated for many hours at a volume which induces wear to the circuitry...