its the easy one, when they blow up, its time to change them...
tubes r generally pain in the a**. they cant stand even for a year. also they have great harmonics in their nature. and u need enough volume for good drive. some of tube amp r not suitable for " low volume neighbourhood playin".
theyr brilliant in general. its tube amp man... eheh...
i wish i had one. yeah constantly changing tubes means trouble, but its worth the grizlin tone...
im not an xperienced tube guy btw... :o
[FONT=Verdana]rest in heavenly peace lil' fox...[/FONT]