Just bought a Fender Rumble 350 Combo. Unboxed and inspected it for shipping damage. Found none. I am meticulous when it comes to my gear. Read and followed instructions for set up even though it is "no brainer" kind of stuff. I plugged in and powered up and struck a low E on my 4 string. All is good. Played my warm ups and turned up about half way for the Star Spangled Banner (no lip sync version 3.0)...no worries. I turned down to a lower practice level and have had a hum ever since.
I am going to borrow a friends ax to eliminate that as a problem. I am using Monster Bass cables to connect with. The amp is plugged into a monster surge protector. The apartment that I live in is the upstairs of a very old house. So, I was thinking it may just be bad grounding in the wiring of this pre Korean war built house.
Any thoughts? I really don't want to have to box this beast and ship it back to AMS. I live upstairs and even with the side handles it is quite the back breaker to move up and down stairs.