Hello all, I recently purchased a 1997 Fender Blues Deluxe Tube amp from Guitar Center (I know, a bit of a risky business). It was playing fine for the day after purchasing it, no weird noises or anything coming from the amp and all tubes looked intact to me. But during a band practice of mine it started to make this very loud constant hum after about 15 or so minutes of playing and has been doing it since after about 5 minutes of use.
I'm really new to using tube amps and am admittedly far out of my depth here so any advice as to what it could be or solutions to this before I bring it into a repair shop would be appreciated. Attached is a video of it in action, none of the tubes seem to be doing anything weird and none of the knobs effect the noise. Thank you!
Edit: Thank you all for the advice and help with this!! Took it to local repair shop and they fixed the issue, one of the capacitors had a grounding issue. Now that it's fixed it sounds lovely! Thank you all again :)