I Myself have become an advocate of Lighter Plinths where materials selected have effective dissipation properties along with attractive measurements for damping properties.
Mass Plinths are in general as a design quite able to add a colour to the end sound. For some loke myself, the colour can be easily homed in on, and can become a detractor and even a cause of early onset listening fatigue, hence my preference has evolved to lightweight Plinths that are not able to create the colour being referred to.
I myself have for many many years been an advocate of overhauling Platter Spindle Bearing Assemblies, these are very noisy when not optimised as a design.
Bearing Assemblies are also able to add a colouration to the end sound, it depends on what proportion of a rotation is Metal on Metal, and how much weight is applied as a result of a Off Axis Spindle rotation.
A Journal Bearing depends on lubricant to fill a very tight tolerance void, to stop the contact of metals. The Hydrodynamic Design for a Journal Bearing is dependent on a different operation to that of the TT Platter Spindle Bearing to be successfully Hydrodynamic and be able to keep the tight tolerance space filled with lubrication, where the oil is the contact surface for the Spindle and not the other metal parts.
A TT's bearing will create a Boundary lubrication when using a typical design commonly offered. Boundary lubrication is basically Metal on Metal as a proportion of the rotation or as for a TT Spindle set up in a typical Bearing Design, metal on metal will be occurring throughout most of the rotation.
How does one avoid the Vibration and Noise Transferred through the Boundary effect?
One method, is to swap out Metal Parts for Thermoplastic with engineering qualities such as Acetal, this is commonly seen today as a upgrade for a bearing. .
Alternatively, create a Bearing Housing that can retain Oil and produce a Housing that can function as a Oil Bath, with the parts submerged in oil, boundary effect id highly unlikely, with the correct viscosity of oil selected to use for the fill.
A oil bath is not an option on a Inverted Bearing, and typical lubrication methods is also another challenge.
There are to relatively easy finds, historical info, to show how not too old TT models using the inverted bearing design, have shown catastrophic break down of the most important interfaces, as a result of metal on metal and applied force to the surfaces.
The OP will be best served if they find a way to have a demo' of each TT, and learn how the TT's Structure and Bearing Assembly is able to impact on their sensitivity to colouration that is able to be produced.
