okay, so now the amp has this hum, the crackling is gone, but the sound gets quieter sometimes, and fades in and out. sounds like someone's rolling my guitar's volume back and forth at points. The amp sound AMAZING like actually awesome - MY sound completely. I love nothing more, but the valves are stupidly hot and i'm sure this isn't healthy for them...
For that reason i've switched the old power valves back in, but the hum is still there, and i'm getting a squealing feedback at high volumes, even with my guitar's volume on 0.
I'm sure that this didn't happen before....
bugger