I have an Ampeg GVT-5h that I occasionally use as a pedal platform. It has a half power mode that I usually don't use, but when I switched it on the other day it gave a nasty hiss sound. The full power setting is not affected. I figured that it probably needed a new tube. The 12ax7 was in there really tight and hard to get to, so I decided to remove the chassis rather than break something or bust my knuckles. Anyway, when I looked in the chassis, one of the capacitors seemed to be slightly bulging on the top and had some discoloration. I was planning to replace this cap before I plugged it back in, but wanted to make sure I'm not overreacting from people that know more about this than me. Is this something that you would replace? The amp is only around 10 years old.