Comparison of sonic qualities of some tonearms

As somebody who has been through a selection of Cart's on the SME IV and lesser Cart's on a variant Rega Design and an TA used in conjunction of a SME version of a Rega Design TA. I have no upset or regret for spending many hours of replaying Vinyl with such a tool.

What is different at present and for the foreseeable future, is I now use a TA that is complete as a design, but also able to be treated with further upgrades of which  a few I am instrumental in encouraging the investigation and resulting realisation of  methods being adopted for both  Mechanical Interfaces and the Signal Path. 

I am thoroughly impressed with the Design for the Tonearm as it stands, when used as a comparison to the upgrade options in place, I am blown away by the changes the few adopted design methods are able to achieve. I don't need the upgrades, I am for my purposes way out in front of my other adopted methods no longer in use for a Tonearm.

The real attraction of the Upgrades is that I know my input to the stimulus that created the curiosity and manifestation of their presence.

As for my posts in this Thread, it is strictly to inform the OP, there are range of TA's as a result of the design adopted. That will impact on the end sound with a similar perception, being a constrained presentation. My conjecture on this, is that it is seemingly being created by the TA's design for a Mechanical Interface, design for the Geometry, or a combination of both.

I will not suggest this is to be avoided, but more to the like that it is to be discovered. Only when discovered will the OP be able to decide if a TA that has a increased perception of being inhibiting or lesser perception of being inhibiting is where they would like their investigations to head.

Note: At no time am I suggesting the noticeable lack of liberty or liberty perceived when a TA is in use, is a perceivable sound signature belonging to the TA design. I do not refer to it as a flaw. I am strongly suggesting that when the perception of a constraining design is discovered, it becomes noticeable, and has a presence as do other influences known for being noticeable. 

For myself it is the electronics that create the sound signature and the failings to manage transferred energies that are the Colouration that can be detectable.  

Leif Johannsen had once made it known the SAT Tonearm used by Ortofon is the only Tonearm, the Company has used that gets out of the way and allows the Cart' to do exactly as it is designed to do.

I am sure I have a much improved understanding of this now I use my most recent  adopted design for a TA.    

@mijostyn You state that between tonearms “The difference in sound quality is so slight as to be made meaningless and subject to psychological overlay.”  
If that were the case, then why would there be so many different types, manufacturers, and grades of tonearms?  It is possible that many listeners are of the same opinion as you, namely that a tonearm makes little difference in sound quality, because very few even discuss tonearms in these threads.  However, in my very limited experience, I would say that a tonearm is capable of making as significant a difference as a pre-amplifier, or phono stage can make.

@lewm The 80's was a time when the MC was beginning to Supersede the MM Cartridge.

MC's are best served with a medium mass arm, well that is what Rega believed and got to work on their designs.

SME were quite focused as a Company of the lightweight arms most suitable to MM's.

The second thing that happened was that Cast Arm Tubes incorporating the form of the Headshell were discovered to be very very attractive by the Press and numerous others, hence Rega's affordable arms were not, according to the mainstream media, just merely a Giant Killer, they singularly decimated legions of Ork's.

Shortly after this nearly all very well established Companies started to make it known about their Cast Arm Tube Designs with formed Headshell and some even had their first MC Cart's produced in conjunction with the debut of the TA.

If Rega had been more protective, the plagiarism would have been a lot less at thei era in time.

Without the Rega on the Market stealing multiple sales from the Big Names, there will not be a SME V and IV chasing its market share.

Anybody who is suggesting a V or IV will trounce a well honed design for a Rega TA is giving very misleading information, the materials used on either might be the only real detectable difference to the produced sonic, the extraction from the Groove are way too similar as a result of the designs for each and how the design allows for the interface with the Cart' set in the Groove.    

The first MC cartridge to make a sizable dent in the US market was the Supex, in 1973-ish. Perhaps your living in the UK gives you a different perspective on Rega and SME, but Rega were a nonentity in the US market until the 80s, and there was no general consensus on materials to be used to build a tonearm back then, just as there is no consensus now.