I have an '85 Marshall JCM 800 100w head and I am running EH 6550's in it, which I noticed are glowing blue. I have heard that when a tube is glowing blue, they are running too hot. Is this a problem for my amp?
Have you changed tubes lately? My JCM800 was biased way too high for the tubes that were in it originally. I think that is a standard though for Marshall to run the tubes hot.
What you're seeing is gas in the tube glowing...not an uncommon occurence...however if the plates (the big grey areas) are glowing orange like the embers in a fire then you have a bias problem
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