Looking at your system photos I am struck by the fact that your problem area is directly beneath the power transformer of your amp.Why this would suddenly become an issue I have no idea.But the first thing I would try is to move the turntable two inches to the right (or the amp to the left).I would try this first because it would be so easy to do.I spent four hours last monday ridding my front end of sudden noise infestation,it can be maddening.When it's back to normal Life becomes so good.Good Luck.
