"A huge crack and one channel of my system died".
This sounds more like a power tube issue to me. I doubt that a failure of a small tube would shut down the amp is the likely culprit. It could be a transitory problem which went away when the amp reset itself. If you have another set of tubes you could always plug them in. Personally I would leave it alone until the problem raises again. Love that fusing set up in the PL amps.
Seems like you have already concluded that the harshness issue is related to the phono section. My guess is that it might well be related to the VTF . I would increase that a bit and make sure your stylus is making effective contact.
This sounds more like a power tube issue to me. I doubt that a failure of a small tube would shut down the amp is the likely culprit. It could be a transitory problem which went away when the amp reset itself. If you have another set of tubes you could always plug them in. Personally I would leave it alone until the problem raises again. Love that fusing set up in the PL amps.
Seems like you have already concluded that the harshness issue is related to the phono section. My guess is that it might well be related to the VTF . I would increase that a bit and make sure your stylus is making effective contact.