shall i even bother changing these tubes? they haven't been changed since forever, that was ages ago, and the fan is pretty loud, sometimes it makes a weird noise, but occasionally.

I don't know much about the AVT though, apart from it has tubes in the preamps, and they are small...

this is my secondary amp, but i actually end up playing on it more than jvm..i think
I don't think you will need to change the pre-amps because it's hybrid and you normally change th preamps every 2-3 years
Apparently a speaker change is a good idea on the AVT range.
They aren't bad amp's at all really, just the speaker can get a muddy and a bit toneless (I wish I discovered about this before I sold it a month ago).

Epiphone Les Paul Standard w/ SD Alnico Pro II's
Fender Aerodyne Telecaster & Stratocaster
Marshall JCM 800 4104 combo

E-Married to Funny_Page
yeah its a good practise amp, and i got it for 350 pounds at the time..that was like 5 years ago.

while we're on the subject of tubes/valves. does anyone know any good books on valves so i can understanding their history and technology...?