Hi all, I have been trying  a set from David and they did make a difference, for the better, I then used the idea and using a larger diameter wood piece approx 25mm and 10mm high, and used 10mm ball bearings this made the whole assy physically more solid and secure, in terms of sound it tightened  all aspects with a more dynamic feel accross the board. Its not night and day but certainly the equilevent of a successfull ic change. For what it costs to make your self its well worth a go. I tried it under my amps but this made no discernable difference so they are used just under the cd player.

Regards

Tony