Silver Supporting Member
Got a 50 watt custom built (basically) Marshall Plexi head, uses a pair of EL34's. Looking in the grill when playing I see that as I pick a string ONE of the power tubes glows brite red/orange around the filament while the other one stays looking normal, just a constant low glow. Is this a potential problem? If so, does it sound like a bad tube or would a new bias setup rectify the problem?