SP10 Mk II vs Mk III

Ralph, sorry for my confusion. Could you be referring to the EPA-100, when you mention "that heavy Technics tonearm"? I have no opinion, but others say this is a really good unit.

Silverprint, I own a Boston Audio Mat I, which is made of graphite. Is that the material you have in mind? As Cpk says, it does seem a little fragile in the context of the mat, but maybe a thick block of it would be much stronger. I think that stuff would be great for absorbing and dissipating energy, but you might want to combine it with something denser, for the mass effect alone.

Ralph, your less than favorable comments on the "OEM plinths for the Technics" must have been intended for the Teak plinth. I first read it wrong, thinking you meant to reply to Lonestarsouth on the SAEC SBX-7 since that was an OEM plinth. That confused me further since the SAEC is so similar to your earlier description of a desirable plinth. To me the Teak looked like something anyone with basic woodworking skills could produce.

Like Lew, I'm also wondering about your possible reference to the EPA-100. I've read nothing but good reports on its construction and performance. If fact, with the adjustable damping feature, it could work with higher compliance cartridges than would otherwise be expected for an arm of that mass, as well as medium and low compliance, meaning it is very versatile.

Albert, when you re-capped your sp10 mkII did you do the drive and circuit boards or just the power supply?

Hello Lewm,

I've been a silent reader for a while... Thanks for the question. And yes, that's the material. It is available in different hardnesses-densities (the densest the harder).
My idea is to use it along with plywood using a very thick slab (about 2') in the middle of the "sandwich", in this way it will be protected, add mass with a diffrent resonace curve, and a quite dead material halfway. That slab will be also used as the base for the armboards (to be done from thick blocks of the same material, that i know is good for the purpose since i am already using it).

To further add mass I tought to make a bottom steel plate "a la" Porter, only I tought to make it bigger so that all the screws of the motor unit will go there. The "screws" will be made out of 1' brass (or steel?) tubes worked at both ends.

Now a few questions, one for Mr. Albert Porter (by chance we are colleagues... funny). Is it there any special warning/advice he can give about the center "screw"? You remove a cup and go in with the screw... but what's there (i am still waiting my unit..)?
The second question is more general. I plan to make those 6 big screws that will pass trough all the plinth and reach the bottom steel plate. Should those screws and the bottom plate have a rigid coupling to the whole structure, or should them (and the plate as well) be decoupled somehow (using a layer of neoprene around the tubes and over the plate)?

...ummm maybe this reading is too difficult (english is not my language, also), is it there a way to post some sketches here?

Well, as usual many thanks to everybody here... all informations and ideas are precious!