My Mesa Boogie is like 5 years old now, but pretty lightly used/played. But It is popping/clicking when it warms up. And when it is turned off/cooled down. Also if I don't let it warm up enough between using it and playing it, it will power off and back on (by itself) momentarily, then continue on fine. I am just curious as I've never had this big of an amp, or an amp for this long. Is this just a symptom of needing new tubes? or possibly a larger problem at hand.