What about Uni Din?

@lewm , I think if you look at phase angles with a given tracking error the phase angle difference between the left and right channels will be three times greater at the very inside of the record than at the very outside. Because the outside is traveling three times faster the peak to trough distance at a given frequency will be three times longer. This makes sense to my meager brain.
@rauliruegas , Are you saying the label edge is at 54 mm?
@intactaudio , I examine every stylus under a microscope. If it is not dead on the cartridge goes back. The beauty of the Smart Tractor over priced as it is is that is has a really nice magnifier making it significantly more accurate than the Feikert. Does it really matter? I seriously doubt it but it makes me feel better.

Can‘t you compare on your own with the Smart tractor? The new Uni din is really worth a try ... specially with high dynamic cut records ( classic originals from the 60‘s) ... I use it.

Dear @syntax : I know you are not a stupid audiophile or an audio rookie.

Any gentleman as you ( including me. ) can’t really be aware of real/true differences in between different kind of alignments but with Steveson one and we can’t do it because the distortion level changes in between groove after groove are really tiny to detect it and the sound is continuous and you can’t detect those changes even at the first null point or even at the inner null point.

So what are you talking about on that alignment or any otehr than Stevenson?, in Stevenson there is a chance you can do it because is a extreme kind of alignment where Stevenson in porpose puts the inner null point exactly at the inner most groove on IEC standard.

Now and just an example if you take the alignment that you are talking about and with the same tonearm and cartridge change it for Löfgren A or B with out changing the tonearm EL the differences if any that you could listen will be thank’s to the differences in the accuracy of each alingment changes you do but not because the alignment it self.

Do you think that when you change between two alignments where you need to change the P2S distance and the cartridge overhang and off-set angle the accuracy on those two alignments were perfect?.
You are rigth, can’t be perfect and exactly same " perfection " on both different alignments.

So if we can’t be aware of differences between alignments other than with Stevenson why are we " figthing " and discussing in to many threads over the internet audio forums?, easy: to have our mind in calm.

So we choose what we think is the best alignment compromise for our needs and that’s all.

There is no way, no matters what, that our alignments ( any ) can be do it with Zero error: NO WAY.

Differences we are hearing in the best cases are because that kind of errors when we made it the alignments and where those errors can’t be avoided and only we can put at minimum but does not exist two similar different alignments ( that we did it. ) with errors at minimum in exactly same way.

Unfortunatelly the alignment is not a " virtual " one kind. So what you are interpreting in your alignment is only a true " illusion " and nothing more. Even using the same kind of alignment we choosed if we made 2-3 alignment set-up ( meaning unmount and mount again the cartridge and the tonearm too. ) at different " times " at each time you can be sure that you will listen " differences " even if you know that can’t been differences because is the same kind of alignment.

R.

Darn, I must be going crazy. I'm beginning to understand Raul.

@mijostyn,  Having looked at lots of stylus profiles under a microscope at various magnifications I think it would be exceedingly hard to confirm zenith angle to say 10 minutes.  I'll side with Raul that even with the best tools setting the same cartridge up three times is likely to end up with three different alignments.  At the scales we are talking about here the possibility for measurement error is large and even seemingly small errors can be consequential.  

dave