I am using three old aluminum cones under the Elise that I have since the 1980's when they were fashionable in Hi Fi. I attached them to the bottom of the amp with blue tack (actually yellow tack from the 99c store).
The tripod works very well, and the Elise is very stable - put two under the transformer and one in the front middle.
Regardless of the merits of the spiked feet, they lift the Elise about 1" off the shelf and thus provide better air flow for convection. The holes underneath and on top in front of the transformer are configured to aid in the convection air flow - bigger openings on the bottom plate.
(These pictures are from the Little Dot MKIII amp, but the footers are doing duty on the Elise now.)
I think that the theory is (was) that spiked feet channel vibrations into the shelf/rack/floor. The spiked feet certainly work in some situations. Remember putting screwed in spiked feet under very heavy 5' speakers on a wood floor - the sound snapped into focus in a very tangible way. Don't know how they work with amps, but I like the idea (see above).
My equipment shelf is sitting on four little metal tabs inside the rack. I put four round glass marbles under the shelf at each tab as another vibration reducing device. Advocated by Steven Gutenberg many years ago. Hey, it was cheap enough (raided the kid's stash of glass marbles) and seemed to make sense, so why not!
The cognoscenti are still debating if clear, green, or blue marbles work best. (This is supposed to be a joke.)
Have fun with the footer Pandora's box!
