The vibraplane is preloaded with 100 lb, so add that to the mass of the component when calculating system resonant frequency, which is the square root of the system spring rate/total mass.
Vibraplane: Should it be loaded close to limit?
I just bought a Vibraplane 2210. It has a maximum load of 275 lbs. I plan to put my unsuspended SME Model 10 turntable on it, replacing my Townshend Seismic Sink. My question is this: Because my turntable only weights about 30 lbs, should I preload the Vibraplane to get the total load with my turntable closer to the maximum load? Will this improve the isolation? If so, what do you recommend I use to preload it? I was thinking a sheet of steel, aluminum or granite. Any advice would be greatly appreciated.