SlipLive

So I was playing the guitar today, and looked down at my powertubes. The right powertube (only two) was almost glowing yellow while the other one looked as it always looks, with the little filliment glowing. I was wondering if tubes are about to blow, that if they start glowing like that. Seemed as if it was overheating.....

Dan

Yeah, it'll spark up a bit, then maybe blow, maybe last a while still. Could also need rebiasing. Replace in pairs. GE mil-spec are best, matched are best. Good tubes are big bucks...used can be ok, but it's a guessing game. Sovtek's are everywhere but you don't have much choice unless you prowl eBay a lot. Try to find a good local repair dude as he might have spares. Groove Tubes are pricey, but can work. Your amp only has certain deviation...can't stray much farther from specs w/o changing bias circuit (hard wiring best done by a pro or you'll wreck the amp). Finicky things tubes are...but so wonderful when they are warmed up nice.