It would seem possible that granite may not jive with all amps. I would try directly on the floor vs. on the stands. For about a year I had my monos directly on the floor with the intention of some kind of stands. As you all know for anything nice well there's another $300+ each. So I ended up using 3" thick butcher blocks. I can't say it altered the sound in anyway, besides that was'nt the goal. They look fine to me and were on the cheaper side. Anytime I want to play with placement they easily allow for sliding of the amps. I suppose if using some spikes under the amps into the butcher blocks it would help drain any vibrations.
