The NAD Branded RB250 OEM1 Tonearm mods
plinth to base
The granite is coupled to the HDF by an old rag at center with cork pads for leveling at four outer points. The granite paving stone still has cement adhering to the bottom from when it was pulled up. The bottom HDF base is supported by strips of cork on each board below it.
Doug Deacon explains it this way: "Sorbothane (whether in cones or otherwise) isolates in the vertical plane down to a certain frequency (which will vary with the weight they're supporting and the durometer of the Sorbothane).
Your Vibrapod cones are reducing mid-high frequency energies from the granite, while the granite mass is providing stability and lowering the resonance frequency of footfalls, probably to a frequency below what your system can reproduce. Sounds like an excellent combo!"
There is a rubber band around the bearing shaft. There is also a small piece of 3M damping material next to the bearing shaft and on the cover of the motor.