I've just turned my amp on and noticed my pre amp valves have a blue glow to them as well as orange. I had the head fully serviced and everything replaced in July but it's worrying me! I've never cranked my head to high volumes and have it on very very low when I practice. Also I make sure my room is well ventilated with a constant supply of fresh air when it's on. Is this normal or does it indicate a problem?
perfectly normal.
Gibson Les Paul Custom
Fender American Tele

Orange Rockerverb 50
Orange PPC412
Normal. Your t00bz r jst gitteng br00tal.

My Valveking tubes glow orange when I have it in standby, and when I actually turn it on and play at high volumes, its a bright orange and blue.
Ibanez RGT42DX
Vox AC30C2
Digitech Whammy (FOR SALE!)
Dunlop GCB-95F Crybaby
Boss DD-20
Boss SD-1
Ibanez TS9DX
MXR M-108 10 Band EQ