My Vox AC15C1 has lost a lot of volume. It's not completely broken though, but if I turn the normal and master buttons all the way up (on the normal channel) I'm still way below my usual volume. Top boost channel is still usable but much softer too (so I stopped using it for now, I don't want it to break further). Also you could usually see the tubes light up after a while, not anymore.
Could it be the tubes? I bought this amp two years ago and I never replaced them. I'm obviously going to see a technician this week but I was hoping you guys could maybe give an idea of what is going on. Thanks!
I'll eat a sock if it's not the tubes.

You could save yourself a lot of money by replacing them yourself. A tech is probably going to charge you a bunch just to "diagnose" the problem which is just going to be replacing the tubes to see if that was the problem (which it usually is). If you replace them yourself and it still doesn't work, then go see a tech.