Turntable versus tonearm versus cartridge: which is MOST important?

As this is a Old Thread and recently received a Post claiming that a non-audiophile does not need to concern themselves with Bearings.

When it comes to a Platter Spindle Bearing, producing a TT, that has a Platter Spindle Bearing which will not show a Platter run off, is a feat of engineering to achieve. To achieve a Platter run off which will show a measurement that has a very low tolerance for a movement, will need certain type of skilled labour at the production work front to hone the tolerances required. This practice has the potential to add substantial cost to the end product. Hence the average TT producer is not going to show the accuracy of their products in relation to a run off measurement, the exposure of the inaccuracies in relation to a Zero run off, will not bear well and will hold them to ransom on QA issues, if they were to make claims of the fluctuations in measurements working within a particular dimension parameter.

It can also be heeded, that as a result of allowed production tolerances for parts being produced, one TT to another from the same Brand/Model can show quite substantial variation in Platter run off. I don't see Parts being discarded when they fall within a certain tolerance, but are maybe at the dimension parameters of the tolerances allowed for.

Take the above and add it to used TT's being purchased, the condition of the Platter Bearing is a unknown, and Platter run off measurements might be further increased to the New Supplied item. When using a used TT, this might be the least of ones concerns, and will only be of a concern when a condition such as a discovered eccentric rotation is corrected. It does not necessarily mean a TT has to have had a hard life  and a long usage have developed Eccentric Rotation, some TT's as a result of the design and materials used at interfaces can quickly develop a eccentric rotation after a short usage life.

There is not a speed control device in use, or to be produced, that can correct a speed fluctuation due to a eccentric rotation occurring. There is not a Isolation design, whether Built into a TT or a Off Board Ancillary, that will stop the transfer of energy to the Cart', that has been generated as a result of a Platter Bearing Interfaces not being optimised, even worse is when eccentric rotation is present. 

The True Rotation and Quietness of the Platter Bearing during rotations, is 'one' of the Critical Factors to be considered that enable a Cart' and the Tonearm to function in a optimised environment.

It is known Vinyl LP users are quite content to use a $10-$15K Cart'>Tonearm in conjunction with expensive devices to accurately control the TT's Speed, under the guise, the expense associated with the ancillaries in use are creating a optimised environment. I myself have used £6000+ Tonearm>Cart in a non optimised environment and can assure one that when the Bearing is improved toward a optimised environment the performance presented is Uplifted to the perception it can seem tangible. 

The use of expensive supporting ancillaries in a non-optimised environment (Non-True rotations of Platter Bearing/ Noise/Energy Transferred), is seemingly quite acceptable. It does seem that the Non-Optimisation of the Platter Bearing during operation, for many, is a lesser consideration, and the Brand/ Reputation of the supporting ancillaries in use are the focus that has the TT users priority. 

The Platter Bearing, Cart', Tonearm are a Engineering Trilogy and are as dependent on each to produce the best mechanical interfaces for optimised performance. 

TT's in most conditions met, are able to function to enable a replay of recorded  music. If this is all that is wanted that is fine, the idea of spending substantial sums on supporting ancillaries is best avoided. When substantial monies are being outlaid to add supporting ancillaries to the TT, from experience, it serves the whole of the mechanical interfaces for the best, if the function is optimised for all critical parts necessary to enable the replay to take place.       

@pindac , with the concentricity spec on records at +- 2 mm I would not worry about turntable runout. I think as long as rumble is low and speed accuracy is high you are in business. I certainly agree that per precision is always welcome and the way all three items interface is very important. The toughest part is isolating it from the rest of the world. 

I'm from the camp, "Garbage in Garbage out" So many people I know that listen to my system say, " wow! those speakers are great! " As far as I'm concerned although a well balanced chain contribute to the end result you hear, It's the cartridge, tonearm, turntable or cd transport DAC that contribute the most. .Another analogy, No matter how "good' the camera, film is, if you start with a ill focused lens,,,,,,,,then what will you get as a photo?

As in all things HiFi, much of what is being created by one within their system, is based on how previous experiences have been a influence.

How would one know an improvement has been made/encountered unless they have a recollection of something that has been perceived as being bettered.

As I am mainly a vinyl user, and have a investment around it, that is for my means quite a proportion of a disposable income, the extra cost associated with working with a Bearing is nominal and the impact a improved Bearing has had is quite something to me. I can't at this present time see how the incorporating of a improved design for a bearing has anything but beneficial and valuable, I know without reservation there is a better environment produced for the other owned supporting ancillaries to function in. My system is where it is and I don't foresee much is to change in relation to devices, my monies today are more available for improving on the mechanical interfaces that enable the best to be attained from a vinyl replay. 

The measurement for a Platter run off is a improvement as a result of a Bearing Design being improved, but the real real benefits, the one I attach to the noticeable improvement being perceived, is the selection of materials used to produce the design. The materials selected allows for new and tighter tolerances for machining over what was previously in use. The machining tolerances and lubricant used are  resulting in a reduction in noise being produced during the bearings function. As said the improvement has the impact to the point it being present feels tangible.

Adding further materials with known properties to manage in a improved manner, what energies are present, takes the overall impact to a further level, but not as the Improved design for a Platter Bearing will have.

Each to their own on the subject of optimisation of mechanical interfaces.

From a commercial view, the tasks needing to be put in place to achieve the condition is time consuming, requires a specialist resource skill, and is costly, resulting in the method being quite expensive to buy into. As not many/if any Commercial Brands are willing to share their tolerances and measurement parameters, not many know what they own in relation to tightest of machined tolerances and remaining with extreme low friction during operation. It is a case of willing oneself to believe the owned Brand has incorporated machining and materials that are the best for the role selected that is available. 

I’ve heard examples of both extremes.
The ultimate responsibility of the tonearm depends on the characteristics of the cartridge.