If you have a tube in your amp that looks like this, you have a faulty power tube. Turn the amp off & take it to a tech to be serviced/checked over thoroughly. IE: The reason we are posting this is that we often receive phone calls & emails asking is this is normal for a tube to glow a bright orange/red, we thought we would share this with you & let you know that this is not normal.
You may be asking yourselves, “Why are you taking a picture & not turning the amp off?” In part to show you what this looks like so you can identify this in the future & also this is a Marshall JCM2000 Series & as you can see, the fuse did blow when a tube fails/shorts.
We have run all the necessary tests & a power tube is in fact faulty/shorted. Please note there are other ways a power tube can short where it lights up & visually appears fine, it looks power white at the top of the tube, etc. Thanks for reading this far & feel free to share or send this to your friends so others can see what this kind of failure looks like. Have a great evening!