Hi there Myles,..thanks for your help,really kind..i´ll try to dismantle my amp to see whats inside,there´s no easy access into the tube socket,hope i can put it all back together again...i´ve read a lot about peolpe changing the tubes and geting a better sound or tone,...
as for Jerry Donahue,i´ve never saw him play live or something,i wish i could some day,..where i live theres not so much live music going,..he´s just a "great" guitar player,..when i was a tennager starting on guitar,and thought at the time i was a bit more into hard rock music,i loved his sound/tone when he was in Fairport Convencion,"Live Convention" was a vynil i listened a lot while practicing,so years latter when dicided to change my guitar´s pick-up i went search into his tone,..kind of...on a more jazzy feel,..best choice really.
Good man,Thanks,...