Tube Preamp Isolation suggestions

I believe a massive stand works the best. This principle is what drives TT makers to use very substantial plinths. You can see that as the TT maker's line goes up in "quality" towards their top of the line, the plinths and overall mass-the table etc. become more and more massive. This is done to prevent the ultra sensitive low output MC carts protected from vibration. Lloyd Walker maker of the renowned Proscenium, TT, insists that not only a massive table is required but that the stand must be very massive as well.
I like the idea of a tube of gas around the whole pre-amp but think the tubes would be the culprit. If you haven't sourced them from a dealer who tests for micophophy I would test them. The tube dampers are never as good as not using a microphonic tube in the first place.

To escalate on what Rlawry stated, Bright Star Audio makes some very good platforms that contain an air bladder inside. I have two, one for my tubed preamp and one for my CD player. I am pleased with them, they work very well, are pleasing to the eye, and are reasonably priced compared to some of the other isolation platforms available. Just note that these types of platforms are constructed for light weight components, certainly not a 150lb amp.

Thanks fro the great responses folks. As always, well thought out and informative. In teresting the comment on the power suppley, which is separate frpm my pre. I have focused on isolating that and it does seem to make a difference. I'll have to investigate these other suggestions further. Thanks.