The necessity of a plinth

Unless I'm misunderstanding something here, by a non-suspension turntable, are you referring to something like an inexpensive Rega that doesn't have a sprung suspension? It still has a suspension, i.e. it's feet.

If you have a non-sprung suspension turntable, the plinth is what everything else is attached to. The motor is screwed to the bottom of the plinth. The bearing well is attached to the plinth and the tomearm is attached to the plinth. So decouple the motor. That's certainly possible. Maybe the tonearm, but I can't think of such a beast at the moment. But decoupling the bearing well from the plinth? How do you do that? The platter is then spinning like a top on a bearing well that isn't attached to anything.

So I wonder if I am misunderstanding what you are asking. If not, then the plinth is simply the structure other things are attached to. That's why it's necessary. Otherwise, it's like a human body without bones.

Have a nice holiday by the way!

Unless you've figured out how to get your table to float in mid-air you've got to set it down on something. A heavy inert platform - a plinth - will help reduce vibration and allow you to hear the record and the needle, not ambient vibrations.

Mark, yes I mean the spring suspension. A turntable with spring suspension needs a plinth to accommodate the springs of course. turntable without a spring suspension don't need a plinth theoretically --> just look at the Simon Yorke designs. You can make a dedicated plinth for the Yorke turntable but I think that would not improve it's sound. In theory the Technics SP-10 also doesn't need a plinth because the motor/drive unit is already encased in a metal cage. You only need to use three decoupling feet for mechanical isolation, that's all. Of course you should make a separate tonearm base to accommodate the tonearm.

Chris

We still have a nomenclature problem here. A "plinth" is simply any type of base or pedestal. All turntables have a base of some sort. The Simon Yorke's plinth is its' round base. The LP12's plinth is the wood-trimed case that supports the suspension, and the Rega plinth is he rectangular board to which the bearing, motor and arm are mounted. The Technics has a plinth too, it is the plastic case to which all of the guts are mounted. I think the original question really applies the the need for some type of mechanical isolation device for a turntable.

Thsalmon: what I mean with a plinth is the often rectangular box (= base) that accommodate both the spindle encasing for the platter and the tonearm. For example the "nude" Technics SP-10 without the dedicated obsidian base already comes with an encasing (as you mentioned) made from plastic (I didn't know that, I thought it was made from some sort of metal). I've read here at Audiogon that a custom made plinth is a necessity to bring the best out of the SP-10. My question is: why does the SP-10 without this custom plinth sound that bad? You can use some of the graphite feet or the Walker Valid Points for under the "nude" turntable for decoupling purposes.

Chris