Sandbox-style isolation

I had my Super Scoutmaster on a Target wall mount but was getting the onset of feedback as the volume went from loud to pretty loud (I have a Vandersteen 2W sub 5' away). By putting a Symposium Super platform ,on the Target, with three Rollerblock JR.'s between the table and the platform I was able to eliminate the feedback completely. Can now crank up the volume (with the stylus in groove and platter not spinning) with no hint of the former feedback/howling. Absolutely worth the expense!!

Dear Cerrot : the Symposium Ultra takes the TNT to another level, associate with a set of 3 rollerblocks Jr. as reviewed by Roy Gregory HiFi + it takes the TNT in the stellar department. Certainly the best upgrade I have done to my TNT.
Second is rim drive. Take a look at my system. Best regards.

Here's my set uf sandboxes, built into the stand (nothing like mass for a TT):

http://cgim.audiogon.com/i/vs/i/f/1155818474.jpg

I still found that putting squash balls under the TT, even though it is sitting on a sandbox, to be very beneficial.

http://cgim.audiogon.com/i/vs/i/f/1231696007.jpg

Enjoy,
Bob

I have built a number of sand box type shelves for various systems over the years. I do think they can sound good and are a good approach for DIY. I built a very nice set of amp stands that looked great and sat under a set of tube BAT VK150SE monoblocks I had. I also had another system that had a set of Pass Aleph 2 monos. I had a set of stands I had built for the Aleph 2s that was a box but instead of sand I used a small inner tube under the top platform. After getting some Grand Prix Audio amps stands for my BAT amps (which by the way were hugely better than the sandboxes) I decided to try the sand box stands under my Aleph 2s since they looked better. I hooked them up and man something was wrong the sound just wasn't that good at all. I didn't even think about the stands, but I just new some magic was definitely MIA. Well finally I switched back to the inner tube the sound came back.

So the verdict that I have came to is that you never know. I know for a fact that isolation can make or break a system, so for any reasonably good system I don't mess around with homemade sand boxes

If you can someway find yourself a vibraplane that is a huge upgrade for a turntable or any component for that matter.

Ejlif, Did you ever try combining coupling and decoupling by placing the inner tube or large springs underneath the sandbox? IME this strategy is very effective (particularly with TT), as is cutting up the sandbox top plate to isolate each component footer.