I have a Clearaudio MontBlanc dedicated turntable stand and it never ceases to amaze me, I can play music loud until their is bass in your chest and the Transrotor Apollon / Clearaudio rack combination are something I never have to worry about. I do not get any acoustical or resonance feedback into the source. My basement is entirely concrete, with double concrete double insulation exterior walls and a concrete ceiling with about a thickness of about 15" inches. yes, the basement is my bomb shelter, haha. I think with the mass of the AC, I would add more mass via a heavy rack for a combined weight of whatever the rack and AC weigh. The Apollon and the Clearaudio rack together are almost 400lbs of mass. I am just too skeptical of adding such heavy weight to the wall, it is a viable option for some, but to me, I rather use a rack first then wall mount last. It seems way too scary for me to see your work of art sitting so high off the floor and then held in place by a rack with anchored points on the wall. See my rack option in my virtual gallery.
Ciao,
Audioquest4life
Ciao,
Audioquest4life