Granite and digital..

My experience with granite has been that it works poorly on most front end components but can be wonderbar under some speakers, sandstone is even better and with less audible anomalies.

I will agree that granite is not a good option for digital. Last night I moved my Marantz 6005 off my top shelf that had a 1 1\2 " piece of granite/cork down to the 2nd shelf to make room for the new SA-10. Wow. I played U2's "Mysterious Ways" and the opening riff was noticeably smoother. No doubt about it. As Spock would say "Fascinating". Today I will move it back and double check. I've tried granite under my TT with mixed results. A lot of dampening seemed to help. Since then I had just installed a 4 inch maple block by itself under it yesterday. I havent come to an opinion yet. I did have an MDF sandwich under it before. 2 pieces MDF with cork then a rubber truck liner in the middle and Herbie's pucks underneath. 

Oh one question. Does anyone sit their spiked TT feet directly on the maple for better coupling?

When granite is placed on top of air bladders or springs the presumed ringing of granite is minimized since the granite slab is isolated from the floor right along with the component. It is also fun to build dual layer mass-on-bladder/spring systems to increase isolation effectiveness. I spike the bottom granite slab AND the component on the top slab. Thicker is better since it will be stiffer and better resist bending forces.

I agree from experience--granite resonates if speakers and subs are close to your components.  I still have my amps and CDP on granite slabs but have solved the problem with footers I have made.  If you want the look of granite, just have some Corian pieces made---much more inert.