Tonearm mount on the plinth or on Pillar ?

Other posts here include testimony by folks who utilize "naked" plinths (none at all, only support columns for the motor unit) with separate tonearm pillars.  They rave about their results.

I've not tried that but I remain skeptical.  Just consider how critical the accurate set up alignment is for the stylus, then ask yourself how that can be achieved when the cartridge/arm mounting is not "fixed" relative to the platter/record?

So I agree with moonglum.  Plus I live on the West Coast where we are subject to earthquakes, some of which go unfelt.  I don't want my tonearm "dancing" around somewhere close to the correct position.

pryso,
Do you play records while earthquake?

According to them the separate tonearm pillar version sounds more transparent and quieter because of the isolation of the tonearm from the TT.

This statement from the original post is false.

The problem you are up against is an engineering issue and is very similar to that of the steering and suspension in a car. Any looseness or flex in that system results in dangerous or scary handling!

Now in a turntable how it plays out is that instead of being scary or dangerous, it works out as a coloration: the platter must be as tightly coupled to the plinth via its bearing as possible, in turn the plinth must be absolutely rigid and acoustically dead while coupling the platter bearing to the base of the arm (which in turn should have no play in its bearings). Any divergence from this formula results in coloration.

The reason is simple: if the platter has any other motion other than rotation (for example a slight up and down that might be imparted from the plinth due to room-borne vibration), if there is any difference between that and the base of the arm the cartridge will compensate (since the stylus has to stay in the groove) with stylus motion and therefore a coloration.

So if the arm is sitting on a separate structure from the plinth, it is open to motion in a different plane and/or frequency as opposed to the platter and plinth. You really want it to move in the same plane and frequency as the plinth so that whatever that motion is can't be interpreted by the cartridge.

I am often amazed at how poorly understood this concept is.
 

czarivey,

As I stated, some quakes are not felt, but they occur and are registered.  So I may possibly have been listening to vinyl sometime while one happened.

But you missed my point, unless you were just being humorous.  The danger would be for my arm position to be shifted during that event so it would be out of alignment the next time I did play a record.  

I'd prefer that relationship (platter/record to arm/stylus) to be locked in place.

And thanks for weighing in with logic Ralph.  

On the topic of quakes it's not just earth movement from quakes but also the rumbles and vibration of passing vehicles as well. Where I live in an urban setting I have a soundproofed room but can still feel big trucks passing as the whole building shakes (as it is designed to do in a quake zone). 

Hence my recent investment in Townshend Seismic isolation which I'll post a thread on shortly -- you can check the attached for details on quakes, and I can certainly affirm that the podium works as promised!

http://townshendaudio.com/PDF/Earthquakes%20on%20Hi%20Fi.pdf