Skeletal vs Plinth style turntables

Ct0517 and RichardKrebs, have you considered filling the webbed aluminum casting of an SP-10 with a dense hard mixture of industrial epoxy and crushed granite(similar to Verdier) or brass powder? This might give the casting the properties of a massive plinth, while performing in conjunction with a rigid skeletal "plinthless" sub-frame. I've been think of this for my SP-10 MkII, together with a turnbuckle between a threaded bearing well and the sub-frame similar but different to the Porter concept.

Halcro, having bushwacked a VPI TNT through flywheel, thread drive with custom pulley assemblies to minimize belt creep, and a Mark Kelly AC-1 two-phase controller, I conclude from experience that that way lies madness relative to DD. IMO there are greater evils admitted through quadraphonic rubber belts than by heroically built cantilevered tonearm boards.

Hi Pryso and Richard, Devcon appears to have soft properties similar to Dynamat or rubber. I lean rather toward passing vibration to earth through mass loading, hard coupling, together with structural improvements that increase mechanical stability of the cast housing and motor. As Richard suggests, maybe at SOTA the stock casting should be discarded. Nevertheless…. the cast housing and motor could be good candidates for treatment via the Flex-tec epoxy system. This epoxy and hardener form a semi-solid that can be sculpted into firm shapes. The casting and motor cavities could be filled and thickened without molds, drips, or overflow. The motor mount bosses could be enlarged to increase rigidity. The epoxy could be filled with brass powder or lead sheets to make a semi-metal or CLD compound, and shaped irregularly to break up and spread out resonant signatures. There… I’ve almost convinced myself to do it.

CT0517, Your skeletal plinth is close to what I have in mind, absent several wrinkles to come. Among other things mine will support 3-4 arms, be compatible with Micro Seiki/Gunmetal pivoting arm bases, and have direct metal-to-metal coupling between the motor spindle bearing and the arm pillars. I’m working with a platform manufacturer with the expectation of making it commercially available for SP-10, Denon, and JVC DD. The business case and cost structure for an initial CNC production run would be improved by anyone expressing interest in this. If so, feel free to PM. Is there room in the market for yet one more supplier of plinths for vintage TTs?