What isolation feet under your amp with great result?

I use sorbothane duro 70  in my sandwiches of bamboo,granite,cork,quartz to controls vibrations and resonance with some success at low cost....

All footers have a sound, and different, dependent on under chassis placement. ***********Google = DRBMP-BLK-01 .......on Amazon....self adhesive rubber door stopper bumpers, 4 pack, designed to stop door knob, from damaging wall. I have used these for years, on all of my electronics. I find them to be Neutral, in SQ......Can use 3 or more under the gear, depending on weight of actual piece of gear ( in place of what feet comes with the equipment ). I have tried expensive footers, including sorbothane, metal, brass, wood, etc. and these, again, have less of their "own sound ". 3 packs will get you 12 footers, and free shipping, through Amazon, and as you might know, Amazon accepts returns with money back guarantee.....my prediction is, you will not return them. Under $10...for a pack of 4.

@jriggy  yes, it proves YMMV. I'm looking for lively. Thanks for the thoughtful reply.

@t_ramey 
EL84's...Nice amp. I am looking for more detail and realism from my preamp. It's a choke point in my system, all other components have been successfully treated with footers and platforms.
The limiting factor with the pre is I only have room for 1" footers due to shelf space, so I'm going to give the EVP's a try. Many thanks.