#1
I have been saving up for about 3 years now and am coming to the point where I am going to start going around and testing out different amps to make a decision on which to buy. Right now I am looking at a Mesa Dual Rec, a Mesa Mark V, Peavey 6505+, Framus Cobra, and a couple of others. Anyway, before I buy something this expensive, I want to make sure I have some general knowledge of the upkeep.

I'm not electrician so I figured I'd come here and see what knowledge can be had from some more experienced people out there who have tube amps and have dealt with this stuff. I just had some general questions, like how often you have to replace the tubes, and what "biasing" the tubes mean and how often you must do it. Anyway, any help on this is really appreciated.
"For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring." ~Carl Sagan
#2
tubes lifespan can be from a few months to a few years, biasing is adjusting tube so that the resistance is a suitable level and that the voltage and currnt going t the tube will not blow it, biasing is done whenever you change the tubes
#3
You only need to bias if you replace the tubes. There are tons of videos on youtube for it.

Power tubes can die rarley anytime really but theres usually a different if you keep blowing tubes. If not, they need to be replaced say once a year, and the preamp tubes can last a looong time.
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#4
Really? I heard the preamp tubes were the ones that had to be replaced more often than the power tubes. What you said makes more sense though.
"For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring." ~Carl Sagan