#1
I have a Peavey 6505+ and I blew one powertube (if looking at the front of the amp, the one on the very right). I can see that it's burnt out but the other 3 work fine. I've removed the outer two tubes to test the middle two and it works fine at 60 watts but I would like to have the full 120. Do you guys think I should just retube the whole thing or is it possible to buy a single powertube replacement without losing sound quality/tone/whatever?
#2
tubes usually go out in succession. So it is best to replace them all.
My Gear
Guitars:
-Gibson Les Paul Studio
-Ibanez "lawsuit" Les Paul
-Ibanez S470
-PRS SE Custom

Amp:
Marshall TSL100
Marshall 1960a cab

Effects:
Dunlop 535q wah
Visual Sound Liquid Chorus

Pickups:
Guitarforce
MHD
#3
Buy a matched quartet of power tubes. Replacing just one means that the tubes wont be matched and can cause some biasing problems.
For those who care.
Current Gear
Cort Zenox Z42
Flextone II
Charvel USA So-Cal
Farida M2 Parlour Acoustic
Admira Hand-built Spanish Acoustic
Blackstar HT-5H
Line 6 M13