Vibraplane: Should it be loaded close to limit?

no it has not changed, the horizotal isolation is what we call a slip-plate technology which is one reason it needs mass to work properly.
Steve
SOS

I just added a 24" X 20" X 1" steel plate for ballast on top of my
Vibraplane. This pre loads the unit by 136 lbs. With the 35 lbs from the
turntable, the total weight now is 171 lbs on the Vibraplane. This is
considerably more than the turntable alone. The Vibraplane is designed to
take a maximum load of 275 lbs.

The added ballast made a significant improvement in overall sound. One
analogy that comes to mind is how my truck rides smoother when the
springs are loaded with cargo in the bed of the truck.

Isolation has increased resulting in better retrieval of low level information. It
just seems like more music is coming off the grooves. The sound is bigger,
bass is deeper, strings and cymbals are smoother and better defined. Noise is
lower so dynamics have improved.

It is an across the board improvement about as big as the difference between
the Vibraplane and the Townshend Seismic Sink it replaced. This isolation
may well be what separates my unsuspended SME Model 10 from the bigger
suspended SME tables.

Photos of the steel plate can be seen on my system page detail images of
SME and Vibraplane. It is a very worthwhile improvement.

Great job Peter and nice to hear again what loading can do when using a light weight TT or CDP.
Enjoy

SYMPOSIUM ULRA STEALTH TOP is the best no weight problems also neutral and very musical.

Peter,

Thanks for your detailed experimentation and findings.