#1
So I was playing through my Epi VJ then all of a sudden, the sound was losing volume (as if I was doing volume swells), crackling noises started popping up then the sound would just cut out intermittently.
#2
Sounds more like a power tube...

Preamps usually start to whine/feedback or very hissy sounding - fortunately its cheap enough to replace both in the VJ, and its a good improvement anyway.
My Gear
Original JCM800
Fender Blues
ADA MP1 Rack

1952 RI Tele
Fender Floyd Fat Strat
Dean Razorback V255
Dean ML79F
Fender Strat, scalloped
Fender Floyd Strat
Ibanez RG550 - 1987 DY, 1990 DY, 2002 BK
Kramer Paul Dean
Danelectro DC59