I use the original Stillpoints with Risers and inverted cups beneath my Teres 320 (85-90lb, unsprung) turntable. They provide a significant lowering of the sound floor vs. the supplied spikes, at the cost of a *slight* diminution of macro-dynamic punch and bass slam. As with most things in audio, it's a tradeoff, but they're a net gain for *this* table in *my* system to *my* ears. Would they do the same beneath another table, in another system or to another's ears? YMMV.
P.S. Agree with Slaw regarding rubber(ish) materials beneath a TT, or anywhere near one. I've tried Sorbothane, Vibrapods and similar in various places beneath my TTs and around my tonearms. The results were decidedly negative: no sonic benefit but loads of added mud. I suppose YMMV, but having heard no audible benefit and serious sonic detriments in several setups, I believe the odds are against it.
P.S. Agree with Slaw regarding rubber(ish) materials beneath a TT, or anywhere near one. I've tried Sorbothane, Vibrapods and similar in various places beneath my TTs and around my tonearms. The results were decidedly negative: no sonic benefit but loads of added mud. I suppose YMMV, but having heard no audible benefit and serious sonic detriments in several setups, I believe the odds are against it.