There are some amp designs that burn a resistor and/or blow a fuse if a tube goes to short or gas. The resistor is the worst of these and usually can be replaced in fifteen minutes or less with a common solder iron. Mind you, not every failure, or even every amp will present this resistor problem when a tube goes. In fact, this is kind of a worst case scenario. The positive thing to think about, and compare in your mind, if a transistor blew (and they do too) you have a real problem in testing, replacing and biasing. Be glad you have tubes, plugging in a new one is like getting a new amp and output stage. Furthermore, if the new tube repairs the problem, you have invested 15 seconds to plug it in. Too bad all things in high end audio are not this easy to make right!
