Alright, what's happening here. Short question: Will a tube red plating for maybe 3O seconds mean it's toast? All the details... New amp. Rockytop 45/50. EL34s London Power Power Scaling 45/Plexi switch Tube/SS rectifier switch NFB switch 8/16 Set switches to Plexi, SS, NFB to 8, and all knobs to noon. Connected speaker cable to left input of amp, and into the 2x12 8ohm cab ((2) 16 ohm speakers in parallel. Plugged instrument cable to upper left input of amp, then to tuner, and instrument cable from tuner to guitar. Turned amp power on, still in standby. Let it warm up for a good 5 minutes. Tried tuning up, but SS2 wasn't recognizing signal, just sat on C. Thought it might be an old battery. Switched it off, still in the path. Okay, I turn the standby to on...and strum a little....no sound. I go to the speaker cab and push in on the jack. Sound comes on. The jack was in all the way to begin with, but it can go in an extra 1/32". When you let it go it slide back out that 1/32." I did pull the input plate and the tip maintains contact in both conditions. Okay, play for 10-15 seconds and it sounds good. I turn the power scaling knob up to 3 o'clock, then back to about 8 o'clock, and then back to 3 o'clock, curious to see what difference it makes (really fizzy at lower power). Anyway now it's at 3 o'clock, I look up and the plate on the right tube is glowing bright. Okay, I'm a tube novice that has read a lot but very little real experience. I stare at the glow for probably 2-3 seconds until I realize, "OH, THAT must be what they mean by red plating!" I turn the PS knob back to noon and flip it back to standby. I think WTF, WTF, WTF. What just happened. Okay, there it is. What do you think?