Inner groove "Rumble"


All of a sudden, I'm hearing a weird "rumbling" once the stylus reaches the last inch or so of a record. There has been no sudden "trauma" to my table or tonearm. The first 80 % of each LP side still sounds absolutely fine. Any thoughts as to what's happening here ?
adam18
To all who have replied with good ideas ---- Lewm, Stringreen, Halcro, Pops, Marakanetz, and Nick --- Thanks a lot for your advice. I'm going to spend some "quality time" with my table and try out what you guys are telling me. I appreciate all your help, and I will post what's happening as I proceed. This is a great example of why I enjoy being a part of the Audiogon community ! Happy Listening to all !
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.
A la Casey's good idea, this speaks also to the question of whether you are hearing "rumble" or "hum". The power amp transformer could induce hum, not rumble.
It's definitely not a "hum." The interference is a very irregular "staccato-like" popping type of rumble, which is now starting to bother me even at the outer grooves of a record. I removed and replaced the belt, moved the sub-platter up and down a few times within the bearing, checked the cartridge wire leads, checked the anti-skate, removed - cleaned - re-plugged the phono interconnects, ...... and still the problem continues, now anywhere along an LP's surface. Oy Vey !!
"staccato-like popping" Can you guess in what frequency range? Rumble is very low frequency stuff, as the name suggests.