plinth for tts8000

Perhaps the WT turntable sounds good in your system. I have a history of finding fault with the WT tonearm. I won't reiterate here.

You found defects in the arm but it was not made of MDF, I was referring to the plinth. :)
That the turntable and the arm were built economically and in a completely unconventional way and against the rules of logic can be argued, but there is no product that is perfect and has no problems in its life of use.
So I wouldn't demonize it, otherwise there would be products to point the finger at even in the hi-end ... don't you think?

@lewm , The torque would be a problem only at start up but you can suspend a high mass (SME) just use stiffer springs. 
The MinusK isolates beautifully, probably better than any other design but it is not user friendly. You have to locate the mass on it just so or it will bounce to one side or another. You have to treat the turntable gingerly or you get it bouncing. 
A hanging suspension ala SME and Sota is the most stable. The Sota is handily the most user friendly because the sub chassis is internalized and you can rest your hand on the plinth to "Q" the record without upsetting anything. The motor is isolated from the sub chassis. During play the sub chassis does not visibly bounce causing any noticeable flexing of the belt unless you intentionally disturb it. Wow and flutter are less than 0.05%. Better yet the turntable is now locked into speed regardless of any change in friction. The hanging suspension is so stable it just does not matter. SME uses a counter belt. Some people use them without it. A solid heavy plinth is simple and very easy to make unless you torture yourself by doing it in slate:-) Get that seismometer app put it on your platter and bang around. Let us know what you discover!  
No, I do not like direct drives and one reason is you can not get a suspended one. I also do not slip "Q" records and do not need the torque. This Sony however is a classic and built like a tank. I can understand the attraction. 

@lewm

It is those planes perpendicular to the compressive force present when slate was formed that I think makes slate a good material for dissipating energy, and why it does not ring, as other "stones" may do

I looked up slate’s hardness compared to other rocks after posting. I knew it was a softer stone. I also tried to find out its porous rating. I found very little except it is somewhat porous. I was thinking that might be the cause. I should have picked up on its layering. Oh well, that’s the "golden years effect".

I have worked with slate before but in the building aspect, not audio. Whenever I ran into a slate, I took extra precautions with my footers. FWIW, I was wondering how you got a piece big enough to even work since it falls apart so easily. I suspect they didn’t use a backhoe.

Anyway, thanks for the reply.

Back when I undertook to make a slate plinth, it was originally for my Lenco, only.  This must have been at least 15 years ago, and there was a "thing" going on about slate plinths, over on Lenco Lovers, or whatever the website is called. OMA made a slate plinth for the Lenco L75, but it was too expensive for me, so I decided to make one of my own.  That's how it all started, just out of my own curiosity. Like I hope I said, I don't ascribe any magical properties to slate except to say I liked the results with the Lenco, and by that time I had identified reliable sources for PA slate (the same slate that OMA uses; apparently slate color and character can vary according to geography) and for water-jet cutting of the slate, so going forward from there was only a matter of locating pdf files that could be used to program the water-jet. (For this work, I thank the guys at RC Waterjet in York.  They were great.)  Peter Reinders, a very nice guy on Lenco Lovers, was able to provide the pdf file for cutting the Lenco slate.  I got the files for the SP10s off another website (Soundfountain).  We created a file for the DP80, using the measurements off the actual chassis.  I made an engineering drawing, and the waterjet guys turned my drawing into a pdf. It was no problem at all to acquire slate slabs cut to my specs by the quarry in PA.  Furthermore they honed both sides to perfect plane flatness and champhered the corners of the slabs, for looks and so they weren't dangerous to handle, before sending to the waterjet company.
Mijostyn, You may be correct that torque is a problem only at start-up, but there is such a thing as stylus drag, which also requires momentary bursts of torque from the motor, to maintain absolute constant speed. I think it may be important to hold all surrounding structures, including the stators, rock stable against the torque that can be supplied by the motor, so all that force (=torque) is devoted to accelerating the platter.  It just seems a good idea.   Richard Krebs devoted a lot of study and analysis to this issue with respect first to the SP10s and then to his own tt design, which I think is now commercially available.  He offers mods to SP10 Mk2 and Mk3, to stabilize the stators on those two turntables.  I've had that mod applied to my Mk3, and I believe I can hear a difference; the modified Mk3 is more "musical", flowing, effortless.  (Not very scientific, I admit.) Because the Mk3 motor is more torque-y perhaps than any other DD motor ever sold commercially, the benefits of the Krebs mod may be most obvious on the Mk3.  Also, Technics opted for tight servo control. Some other DDs, e.g., my Kenwood L07D use a more relaxed servo feedback system, and indeed the L07D is exceptionally musical and flowing in its SQ, as is. Not to mention it also has a coreless motor, also a good thing. (We agree, Artemis.)

The 'Link' if scrolled through will show the various Trade Names used throughout the Globe for Densified Wood such as Panzerholz.
Most of these have Bullet Proof Properties,
hence Panzer (Armoured ) Holz ( Wood ) 
Permali is used to make Bullet Proof Panel for Military Helicopters.

The amount of Lamination Layers to a given Thickness is one thing that may separate certain brands.

If a Plinth is desired that measures dissipation and damping similar to these Materials, then there is also the option to investigate
Polybentonite Resin Formed Plinths, these can look extremely aesthetically pleasing and are liked by users of both DD and Idler Drive TT's.    

Another TTS 8000 owner I have communicated with in the UK, 
uses a MU25 Birch Plywood / PolyBentonite Resin / Corian Arm Board designed Plinth.
He Prefers this to many other configurations of materials he has used.

Newplast Modelers/Sculpture Clay is another material that will help a lesser material show improved dissipation and damping measurements.

https://www.diva-portal.org/smash/get/diva2:993130/FULLTEXT01.pdf