#1
Sorry for another thread, its hard to get peoples attention at this time of the day =)

So preamp tubes are harmless to replace. Now powertubes. How do I make sure theres no risk-factor? Just leave the amp off and unplugged for a while, then dive in? The ValveKing has a fixed bias so dont need to do any biasing.
Epiphone G-400
GFS Crunchy PAF - Bridge

DigiTech Bad Monkey
iSP Decimator

New Amp Fund: Depleted
#2
Preamp tubes shouldn't need to be replaced... Based on the way you are asking these questions, its obvious have no idea what you're doing. Go to a pro. If you feel you must do this yourself....

I don't know what you mean by no risk. Of course you need to turn the amp off, and it needs to be cool. Make sure you use matched tubes. Try not to touch the tubes directly, finger oil can create weak spots on the tubes when heated. Also YOU DO NEED TO BIAS YOUR AMP. Fixed bias DOES NOT mean you can just stick tubes in there and hope for the best. In fact, fixed bias amps need to be checked more often than cathode biased amps.
Suhr Custom, Flaxwood Rautia or Grosh Tele thru
HBE Medicine Bawl Wah
Analogman BiComp
Texas Two Step OD
Fulltone Ultimate Octave/Fuzz
Boss CE-2
TC Nova Delay
SLO-100, 65 London or Bogner Shiva
Ask me about any of this stuff!