What defines a good tonearm

my perspective is that the most significant percieved and discussed weakness of a unipivot is actually it's biggest advantage, which is the freedom to wiggle. it is the micro and nano wiggling following the groove unimpeded that gives it the advantage over a fixed/gimbaled bearing pivoted arm which on the micro and nano level cannot follow the groove as well.

A tone arm should not really follow the groove- it is the cartridge that must do that. The arm must keep the cartridge in locus. If you think about it, if the arm *really did* follow the grooves the cartridge could not make any sound! Thus we come to the idea of effective mass the the ever-important issue of mechanical resonance.

Unipivots however do not rule the roost by any means when it comes to freedom in the motion of the bearings. For example, the Triplanar arm employs an ultra-hard bearing that is so hard and so precise that Triplanar got investigated by the Department of Homeland Security because they were using more of these bearings than Boeing was. Triplanar maintains that a problem with all needle-and-cup bearings is that the bearings get damaged after only a small amount of use- whether gimbaled or unipivot design. That is why the bearings they use are so hard- 7 or 8 grades harder than the bearings in an SME 5.

The Triplanar has an adjustable azimuth system consisting of a worm gear that can tilt the arm tube. If you look at how a cutting lathe is built, its obvious that the azimuth of the cutterhead never changes- the cutter assembly rides on a extremely precise machined stainless set of tracks with stainless wheels. As far as I have seen, (and microscopic motion being the nature of LP reproduction) only a gimbaled arm can have the same kind of azimuth accuracy.

I don't care what fancy gimbal bearing you have you cannot beat a needle on a dimple.

That is of course exactly how the bearings in the Triplanar are built. Except they are about 8 grades harder than the hardest commercial bearings, DHS notwithstanding.

Gimbal arm does not guarantee azimuth accuracy. The Triplanar's way azimuth adjustment is placed before the offset angle at the headshell, unless the worm gear is angled accordingly--approximately 23°--that adjustment will affect VTA.

In this quote, the former statement is in no way supported or detracted by the latter statement. However the juxtaposition suggests that the latter statement is being used to support the former. This type of argument is a logical fallacy known as a red herring. A logical fallacy is by definition, false; this example is not an exception.

It is a simple fact that once set, the azimuth will not/cannot oscillate on a gimbaled arm as it is held in locus. That is a not feature of even the magnetically-stabilized unipivots, although the use of magnetics did dramatically reduce that oscillation and is a major step forward for them.

I use master recordings for reference. Its the only way I have found to really know if you are on the right track. So for me its not a 'cup of tea' thing. I'm just trying to get the LPs to sound as close to the master as I can.

Hiho, you can look here: http://www.nizkor.org/features/fallacies/red-herring.html

I've pointed the link to Red Herring but a number of other fallacies are described. I've found the site really helpful over the years as I found myself guilty of some of these. The more I was able to drop them, the easier my conversation has become! The explanations are terse, but its worth wading through.

Dan-ed, I came to the opposite conclusion regarding the Talea. I thought I heard better tracking and a more stable soundstage (similar to tape playback) with the Triplanar. However my exposure to the Talea is limited, and it was not a particular target of my comments. In my eyes it has yet to prove itself but is clearly a contender. I've still got unipivots in the stable...

Mike and Dan, I assume that both of you have LPs that you recorded yourself and released commercially. What is the title of the LP? I'd like to get a copy.

Dan_ed and Mike, are you attaching meaning where none existed? I really did assume that you and Mike did have such an LP, as I know others in this community for which that is true. I just wanted to get a copy.

As for the Talea, I refer you to my previous comments about the arm- it seems to me more was read into them as well.