Broken preamp tube?
Hi everyone, my Peavey Valveking II just had a weird failure right after I flipped the power switch. I hadn't even started playing yet.
One of the preamp tubes (12AX7) suddenly started glowing extremely bright, like a lightbulb. While it was glowing, the amp was making a very faint, quiet scratchy noise (like frying bacon or a dirty jack).
There is now zero guitar signal and the Volume/Gain knobs don't respond at all. The faint scratchy noise continued until I shut it off. Before this, I had some microphonic ringing on specific notes (F/C), but the amp was working.
The tube getter is still silver (no air leak). Does the "lightbulb" glow and the silent signal mean a plate resistor or internal fuse is gone? Is it worth just swapping the tube, or is that faint noise a sign of deeper PCB damage?