i hadn't used an amp in a while, and when i turned it on today, it seemed like it was quieter than i remembered it. looking inside, one of the tubes was glowing less than the others, but it's still on a little. did i burn it out? is there a way to check for sure? the thing is, i also seem to be losing a lot of volume going through the pedalboard as opposed to straight into the amp, which i didn't notice before. tone loss, sure, but not volume loss. what's going on?