Ever experimented with double sided Scotch tape?
With clean hands, try a piece on the underside of a component, so that it is also in contact with the vibration control device. Or between the original feet, and the shelf. If you have removed the feet, place the tape
between the shelf and the bottom of the vibration control device.
Try this anywhere two pieces meet where electric current is not
present... supporting components, wall treatments, HFTs,
securing cd mats to cd platters...
I think the tape comes in different widths, and is usually available
at craft stores or online.