Turntable and Rack vibration control


Hi,
I moved from a Nouvelle Platine Verdier to a Loricraft Garrard 301. The big change with this move was that the Verdier comes with a terrific implementation of pneumatic suspension feet which kept the TT almost floating and hence great isolation from vibration. The result was always a noise/grain free playback and super clean backgrounds. With the Garrard, the plinth is typical custom made stacked birch ply with standard steel cones as footers. When placed directly on the rack the background is noisy, the images muddle up and overall music is not well sorted.

I do not expect the Garrard to be as quiet as the Verdier but I know it should not be this noisy either. In fact the Verdier also sounded noisy when I placed it directly on cones bypassing the pneumatic suspension feet. 

I use a Hutter Racktime rack which is not like an overbuilt audiophile rack. It is more like an open frame rack with lightweight supports. It is a bit like a Rega TT, not very damped or controlled. The rack has pointy steel feet which rests on brass spike plates (mine is an wooden floor). I guess this implementation is not sophisticated enough to keep away vibrations and let the TT play quietly. 

I am looking at two levels of solutions:
1. Replace the existing steel feet and brass plate with a quality vibration control footer below the rack
2. Replace the stock steel cone below the TT plinth with a better footer/platform.

I have tried Sorbothane, Squash balls kind of tweaks, while they reduce noise they slow down the music too.
I have also tried Stillpoints and Finite Elemente footers under the rack. They make the sound thin and metallic IMO. Platforms like Minus-K are too expensive so I have not considered them yet.

I am looking suggestions here, probably footers and vibration control devices that are more musically oriented yet well engineered like Shun Mook, Harmonix, SSC or something like an HRS platform ?
pani
Here’s a little trick with marbles. You need three large size glass marbles and three glass or ceramic shallow bowls. The ones that are used as bases for those small incense candles are perfect. Then all you need is a glass or ceramic top plate which is placed directly onto the three marbles. Then balance everything with the component sitting on the top plate so the marbles are centered in their bowls/cups but free to move in any horizontal direction. For this to work correctly there can be no cables pulling on the top plate, etc. so the top plate and component are free to move very easily.

@pani- you said "When I tried some softer footers, it did wonders to the sound by bringing back the air and lowering the noise floor, just that it was again not a full proof solution."

What is missing, in your estimation, to reach the 'full proof solution"?

I would think some of the 301 users with various plinth set ups ought to be more help to you. 

Bill Hart (f/k/a Whart) 
Till now I have tried to keep things simple with my garrard by using a good multi-layer birch ply plinth and using some cones to rest it on the rack. But it is now getting painfully clear that this is not a very well-sorted system. The noise floor is high, the images are grainy, the air and tranquility is missing. When I tried some softer footers, it did wonders to the sound by bringing back the air and lowering the noise floor, just that it was again not a full proof solution.
This suggests that the plinth thus created was not dead- and may have been imparting vibration coming from the stand. I say this because the soft footers helped, which suggests that they are isolating from the vibration source.

This is why a massive platform is helpful- it can be isolated from the stand if need be by the squishies and then the 'table hard-coupled to the platform. But that only works if the platform really can sink the air-borne vibration away from the 'table.
Proof is in the Pudding!

Download free App, "iSeismometer" (three axis sensitivity), put your smartphone on turntable platter and check out different turntables, racks and isolation schemes. Play loud music, use subwoofer, bang around with your foot to simulate footfalls; see the results for yourself. You’ll be surprised to find out what really works and what is just a myth.

Lightweight JA Michell Gyro SE (spring isolation) proved isolated while, Pro-Ject Xtension 10 Evolution (magnetic decoupling feet, 22 kg weight...bla bla bla ) was disappointing.
I would first try to take the table off the rack and put it on some amp stand with metal cones or even simpler to put the table on a 2"-3" maple platform with cones under it. May not be convinient though and sure may not work. I have Nottingham sitting on 3" maple block with Boston Audio graphite tuneblocks under the block on the floor, the wooden floor in an apartment. I wouldn't want to dance or jump near it but walking is fine, and everything sounds right to me.