Skeletal vs Plinth style turntables

Hi Richard
I said the SME's are skeletal on the basis that they are quite open as you observed. I must say I do quite like SME's. My problem with the double deck turntables is that dust can gather - however clean your room -trust me I have one such deck.
I have in mind the use of adjustable oil filled motion control dampers (used for microscopes) and heavy elastomer springs. It will hopefully allow me tune the deck but not be too springy or overdamped.
Who knows maybe I can rope some local gonners into doing some listening tests at my home...

Here is the issue in mechanical engineering terms. It is not a lot different from the steering and suspension of a car.

In a nut shell:

the plane of the platter must be consistent with the plane of the cartridge. As the arm moves the cartridge must remain in this plane. Since the platter must revolve, there can be no slop in the bearing such that the platter can deviate from said plane.

As the arm must be set at a fixed point, it can then be seen that if there is any difference that occurs between the point of the arm and the surface of the platter that is will manifest as a coloration of some sort.

For this reason, the coupling between the surface of the platter and the locus of the cartridge cannot have any slop of any sort. To this end, the coupling between the bearing and the base of the arm must be as precise and tight as possible; IOW of a singe piece which will not respond to vibration, as if any differences can occur they will be interpreted by the pickup as coloration.

What this means is the more dead and the more rigid the plinth is, which also holds both the arm and the platter, the better the 'table will sound.

Parrotbee
I look forward to you posting pics of your creation. Good luck with the project. Also can you advise more details on the microscope isolators?

Atmasphere
Dimensional stability.... You said it far better than I

Thanks

Hi

I must say that I am not a big fan of arm pod mounts for turntables because then you are reliant on the platform to couple the platter cartridge arm loop - I am sure some will outcry at what I have said, but I think arm pods are quite a clumsy solution to a problem.
I had a look at few different large microscopes, and they have motion control dampers - I am looking into the best VFM/performance ratio.
I am gonna post, at some stage, a full set of pics from my drawing board plans to the build.