Skeletal vs Plinth style turntables

Halcro and Lewm - it's like those two old men on the muppets - always arguing - probably really the best of friends/enemies??? Funny thing is that both write about some of the best posts on this forum from my reading.
What Halcro says then explains why people like Mike Lavigne are using very expensive microscope stands in their systems.
That said don't RIAA filters etc cut out above 2-5 hz?
I guess I am gonna have to put theories into a design, and then tune using my ears.

Dgarretson
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.

@Dgarretson

Hi Dave - did not realize you picked up a SP10MKII. another TT ?
Filling the webbed aluminum casting sounds like a good idea. But when you say "plinthless" with my set up it is not the case. if i can backtrack.

I got to about Version 8
with my SP10 project (two + years ago?)

The plinth can be seen as the black base that the stainless steel columns and pod are bolted into.

It has not been touched in a long time.
I admit its looking kind of stale and I always meant to replace the current black base with a more aesthetic one.
This hobby is very much an exercise of Function over Form for me. The tonearm attached to the POD is a leading example of this.
If for some reason one "hears" a mismatch in resonances, the ET2 provides resonances tuning capability.
If I had continued with the SP10 I had thought of maybe dropping its black pants and have a look at how things can be cleaned up. I discussed with Richard Krebs, sending it to him long ago.

I have also though of maybe give the SP10 some balls ?

however.... as I am really enjoying not reporting to a boss (wife not included) I need to be selective with funds for the hobby as I have two 20 years olds grabbing cash at every opportunity. Its not a priority and the sp10 is in room 2.
All my vinyl listening is on La Platine in room one.

fwiw (sorry to digress Parottbee)
My turntable phase was a very slippery slope for me. It came at a time when I needed something to take my mind off other things.
I am very grateful for it and I learned much with my SP10MKII. I am happily a music lover these days, with no desire to tinker, although I don't mind talking shop on the forums and discussing past experiences. I did have at the height of my own personal madness - three tables, modded VPI TNT ( thread drive), SP10MKII and Nantais lenco table (which btw used to be his personal table), all next to one another like babies in a nursery. I had the same tonearm / cartridge going with two of them at a time, and it was alot of fun comparing to 15 IPS master tape dubs - very revealing.

Back to the thread theme if I can just say that discussing the type of plinth is only one aspect of this. The platter system is very important.
For example the Jean Nantais
here is what the platter looks like

I have a copper mat I can use with the technics.

The Verdier however again sets the mark - a solid aluminum platter designed to be used Naked.
With the magnetic levitation the natural action of magnets producing a braking action. So you have acceleration inertia and and braking due to the opposed pole magnets to deal with the records behavior. Add to this a solid aluminum rigidly attached pod, a different material brass spindle to interact separately from the platter. oh yeah also no bearing....... Just bloody brilliant. Continually amazed by the simplicity of it. In all my years at this hobby probably the best thing I have acquired right there with my SP11 (and my records)

Henry - Lewm seems to showing (again) what we in Canada refer to as - possible signs of cabin fever. I could be wrong . But if I am not mistaken there have been some bad snow storms in the US lately. :^)

God, these analog threads make the digital ones seem SO BORING....... no more coffee for me. :^(

Cheers

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?

Hi CT0517
Hijack the thread all you like - ;)
You said a few interesting things about the Platine, because the base is very much made of a similar material, by the sound of it, as the Technics Obsidian Bases or the Sony Reisinamic Plinths - both of which use 'resins and stones'.
Likewise Townshend Audio used to use Plaster of Paris.
I have to say I auditioned a Platine, and at the time I was not seduced by its charms - I found it a bit too warm for my tastes. That said - I am not knocking what floats your boat.
With regards to filling in the SP10 - Can I just suggest that you are a bit careful - why not try some lightweight damping such as acoustic foam first of all - what frequencies are you trying to damp?

Hi Chris,

Glad to see you're off the DIY and enjoying the music...as Raul used to say?
Here is a 'suspended' nude Victor TT-81 design using the same idea as your coupling 'plinth'.
It all depends on what one 'means' by a plinth?
If an added shelf sitting on a shelf qualifies as a plinth....well, that's exactly how a turntable plinth acts.
If one removes the 'added' shelf (plinth)....could someone please explain the differences to the mechanical and structural functionalities?
I do appreciate the added 'warm and fuzzy' feeling this can impart together with the ability to mechanically fix the tonearm pods if their weight is insufficient....but apart from that...👀❓