Turntable isolation platforms

I think if looks are important, Adona gives a lot of bang for buck.  Otherwise, I would not spend big bucks.

Are you sure it's acoustic feedback, i.e., sonic degradation from the volume of the music?  Or do you mean isolation from footfalls and the like?  If it's the latter, a wall shelf makes a huge difference IMO. 

It's definitely acoustic feedback.  If I rest needle on record and turn up volume I get rumble.  I then had a friend apply pressure to rack and the rumble stopped.  I need to isolate TT better

Perhaps look at the Townshend audio spring isolation platforms? All of those type of affordable "audiophile racks" - Pangea in your case, Lovan Sovereign and VTI (ugh) in my past - are gonna make you have a bad time when you place a turntable without a spring suspension (maybe OK if you have concrete slab floor, though), especially if you like to crank the volume up. SOTA Star/Nova, with its excellent 4-point suspended subchassis, worked just fine on the Lovan rack. But a Clearaudio Innovation - not so much. A really expensive rack (Critical Mass Maxxum) also completely solved the issue for the Clearaudio deck, but at exorbitant cost compared to simple & effective springs.