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