After about 3 months of very light usage (home use, ~20 hours), my Code 50 developed a harsh noise problem: https://youtu.be/S2cTK8fsfTE. It's on every preset and can be heard via the speaker and when using headphones. I tried using different guitars/cables/power cords/rooms/outlets, reloading firmware, and resetting the presets to factory default; but the noise continues.  Anything else I can try before I return it for replacement/warranty work?

So I've been thinking about buying a Celestion F12-X200 speaker for my code 50 and was wondering it this would work. The reason I need to know this is because even though I know you can use an 8ohm speaker on a 4ohm tube amp, I'm not sure about a digital amp. Could anyone tell me if this is possible.