Simple & Cheap Way to Cut Turntable Vibrations

Bifwynne, Mike has a good idea. Essentially Herbie's Audio "Isocups"
with "Supersonic Hardballs" are naught but small "dead"
squash-like balls. And they should work well. The Herbie's part is cheap
enough to consider, and the cup he supplies will keep your balls from rolling off
the shelf, if you will pardon the image.

Phasecorrect, Thanks for your support. Have you tried it? I use Stillpoints feet
with their supplied cups, but I mount each of the 3 feet on a stiff sheet of
plexiglass which sits on a 3-inch thick piece of industrial styrofoam packing
material (3 separate rectangles of the styrofoam, one for each footer). The
plexiglass is a practical necessity; this particular turntable is so heavy (~90 lbs)
that each footer was slowly deforming the "styrofoam", after long
term settling in. This rendered the turntable out of level. The plexiglass just
distributes the mass of the tt over a wider area of the styrofoam and keeps the
level adjustment stable. The whole thing sits on a composite granite Adona
shelf in an Adona rack. (So I guess this system is disqualified from "cheap".
However, the styrofoam packing material was free.)

Yup squash balls under my VPI too. However I did it a little differently. Put the TT on a maple butcher block cutting board, then put about 9 squash balls between that board and the table top, making a cheap man's Ginko Cloud. You can rearrange the balls to put more under the heavier table spots, like the motor, to balance it out. Over time these compress much more than initially, so you should check your level from time to time and adjust.

This setup passes the knuckle wrap test (stylus in a groove, record not spinning, rap on the supporting table top/leg - no sound through the speaker).

Enjoy,
Bob

Yes I am serious.
The squash balls work great!
They are designed to do just what we want them to do in our application. Absorb
vibration and convert it to heat.
One thing I would add. You want the balls to compress under the weight of the supported equipment enough that the feet of the equipment do touch the supporting shelf or table, what-have-you.
Give it a try. I think that you will be pleased with the effect.

My balls squashed completely.

I had a dozen or so under each of two concrete paving slabs, one for the TT and one for the CD player, and the weight was too much for them. (Insert joke of choice here.) The squash balls now look a bit like big red blood cells. In any case, I wasn't sure they were doing anything for isolation anymore, so I now use an inner tube under each paving slab.

Since I first read this thread I've added the felt pads--they work!

And if anyone else uses innertubes, try a tube with a presta valve (you can get them at any bike shop or from Amazon)--they hold air better than standard Schrader (automotive) valves. You might need a presta adapter ($.99) if you have only a standard pump...

My balls squashed completely.

No pain, no gain ;-)