Dumped the rack


So I have a steel spiked Sound Organization table about 2 feet tall. On it rests a 3" maple butcher block. On that rests my slate Garrard 401 with slate feet and aluminum cones.
I had a piece of granite made and installed it on the maple beneath the turntable. Man, that sounded bad. Silvery colored and dull. I reversed the layer order and put the granite below the maple. That sounded a lot better. But not as good as when there was no granite. So I took it back out. Okay back to how it was. But something was missing. The granite did bring a feeling of stability to the image. What to do? I took the whole rack thing out of the equation and put the 401 on the concrete floor along with the preamp. This sounded best notwithstanding the wooden tone lost by removal of the maple. But the best thing, and I’m aware of the effect from reading but never tried it, was that imaging has improved by quite a margin. Like removing a veil of something. Like when someone moves their head out of your face at a concert. Now, I have to bend down to play records. 
128x128noromance
Oranges and apples, maybe - I don't have a TT, digital only, I have a cheap media table I used as a rack, thought the tube amp was already well isolated, but my results were like yours, great improvement when I removed the table and put things on the floor, and I haven't even cleaned up the cable runs yet.  I think gobsmacked is the technical term for my reaction.  I was so surprised I went back and forth a few times to make sure, which was a bit of a pain, but hey we like to suffer for this hobby. 

Would a good A:B test be to move the rack to a sidewall, maybe that would determine if it's isolation or reflection that's the culprit?  Might provide direction for next steps.  
Having a tt set-up on or close to the floor is not an option for me or one I'd consider.

Besides the obvious...there's the cleaning of the record/stylus and other normal maintenance.
Concrete has much greater mass and a much lower shear speed than any component of your rack or device in contact with your turntable...Off the table on onto the floor has lowered the center of gravity and reduced the resistance of rotation by reducing inertia. The source of rotation is near the ground point and not on a wobble 2ft.  above the ground point. The turntable as it rotates has to over come the irregular forces from the ground point to the spindle. These forces can be amplified by distance as the propensity to wobble becomes greater.Tom
A proper wall isolating system will overcome the issues in the previous post.

BTW, the tt mat I promised you, will be sent in a few weeks. This (may) address some of your issue in addition to just sounding good?
You mean a sounding board? How would that isolate anything...how many square feet is that sounding board? Tom