Aiyo I need to change my powertubes la. My amp has been making crackling sounds at higher volume. Damn hard to get Sovtek 5881 over here.

I have to add that the speaker reacts differently at differently volumes. I use a some sort of attennuator on my amp, even when the master volume is at the same level, but the volume is lower, the amp sounds like shit. If you're gonna need a practice amp, better get a small tube/solid state combo with a nice 10" speaker (5w might be considered small but it is really loud).