I must have led a charmed life. Not once has one of those hot finicky antiquated tubes ever let me down. Pots, fuses, caps yeah, but never tubes. I'm sure I've been lucky and tubes do give problems but I'm also pretty sure some comments on this thread have exaggerated the issue. I'm also pretty sure Mr Norvell and others are exaggerating the supply issues too. Ongoing demand from the guitar amp and high end audio markets will ensure ongoing supply.