I stumbled across this 16", 2.5" thick turned aluminum billet at Baetaffs salvage, and thought "dammit I can make a plinth out of this somehow!" I bought it for $40. This design took a year or two to evolve, because I only had one chance to do it right (I didn't relish the 1-2k$ cost of doing it from scratch)
The final design evolved from reading the original Teres email digests, and seeing the work that Chris and the RedPoint guys were doing. A key to a good 'table seemed to be that of sinking vibrations, both from the platter, and from the room. To sink means you must first transmit them to a place, then dissipate them away. Oil and lead shot is an obvious "black hole", and aluminum is very good at transmission.
This plinth was already machined with a 1/2" cavity in the bottom, and a 1" cavity at the top. I personally machined a center post for the bearing, and a threaded post for the sensor to the side. I milled smooth a spot in the center (it was a rough turning from it's previous life), and drilled out the 1 1/8" center hole, and 1/2" hole for the sensor. The sensor post was easily turned, and threaded on the end with a 1/2" thread. I also drilled holes for bolts for the center post, so I could take the platter off and the post would stay. A little silicon as extra protection, 30 lbs of lead shot and two bottles of mineral oil and I'm done. Plans are to make a wood top plate to cover the lead, and it's already drilled and tapped for bottom spikes. The arm pod is good (lead/oil filled), but the arm board didn't work out. A new one is in the works. I'll do a fine polishing too.
What does it sound like? A black hole. Comparing it to electrical signals,
it's at "ground". It's not dead or lifeless, just non existent.
-- Daniel