I have a very heavy TT--Lenco w/ Pete Riggle Woody arm. I get no howling or feedback when playing records. The TT weighs about 115 lbs. and sits on a Star Sound Sistrum rack's points. There are 2 other components that are on shelves on that rack also. I have 2 sets of racks so they are much lower than a tall one. Mine used to be 4 ft. tall but I had Star Sound cut the support rods so they are about 1/2 as tall and a even more stable.
Bob
Bob