Uni-Protractor Set tonearm alignment

Dear George, that now is a question/comment worth being addressed.
The Talea, Schroeder, Clearaudio, SY and before them other tonearm designs ( Well Tempered et al) did use this smart trick for good reason.
By this design feature they avoid a pre-determined offset angle and thus are much easier to adapt to different alignments (calculations) without trade-offs due to the alternation of a "pre-determined" offset angle by a cartridge's body aligned in a different angle.
Circular bodies further reduce the problem, but - unless they follow the Ikeda or DECCA/London cantilever-less principle - there is still the line of the cantilever which should be in line with the offset angle.
If we have a cartridge body other than circular, the problem get's worse and if the cartridge's body and its cantilever aren't in line with the headshell's offset angle, we will get another force vector - i.e. a second breakdown torque and thus an alternation (not necessarily an increase!) of the skating force the tonearm can ( NOT must!) apply to the stylus/groove contact.
Before I address your statement regarding skating force and "anti-skating", please clarify what you think skating force is and where it comes from.
There are a very few pivot tonearms out there with apply practically zero skating force to the stylus.
Cheers,
D.

"There are a very few pivot tonearms out there with apply practically zero skating force to the stylus."

Why are you mention this? Are they having an advantage over the rest tonearms? I thought that as the friction increases towards the center of the LP, we can not assume the skating force as a constant value and so, we must apply an increasingly antiskating force anyway. I'm I get it wrong?

I spent an afternoon with the Uni-Pro.

The following is my own impression and opinion:

The Uni-Pro came packaged very very well. All parts were in protective pouches, etc. The PDF manual is excellent. Easy to read and follow.

I initially took a gander at my LPs and found most were not even IEC standard and the grooves ended well before. So I chose Lofgren IEC template to start.

The set up of the Uni-Pro is very simple and the build quality is top notch. I felt great to having this tool to use.

The set up using the Lofgren IEC template with the Uni-Pro was the easiest of all my jigs and protractors. The 10x loupe positioned perfectly and I was able to really see the cantilever in relation to the alignment lines. The parallax lines really help out to know that your head position is correct. So much easier than the Mint with the supplied 10x loupe which can roll easily and hit your cartridge. With the Uni-Pro loupe, it was a cinch to know for sure. It allowed for me to really see the cantilever of my Grado Statement1 which I was not able to do with Mint loupe.

The Uni-Pro also comes with nice extras like LED light which came in handy, ruler to measure P2S distance, and other goodies. Even gloves for the super obsessive! Great, as I am a bit of that.

I will try Daniel's VPI 10.5i template next and then try the Baerwarld IEC as well. To note, I did not like the sound of Lofgren IEC and reset my cartridge to VPI's own jig which has a sweeter timbre and less harshness on grand pianos. So it makes me realize Harry at VPI knows what he's doing although some here seems to consider his methods suspect.

Finally, I am not a tone arm physicist or anything like that. I am just musician and also a recording engineer who work with my ears daily musically since I was 2 years old.

Is Uni-Pro worth the 700 bucks? That would be up to the individual and their wallet. For me, it was a great purchase as it makes setting up my cartridge so much easier with no fuss. So a yes for me but I am in NYC where a nice evening out with your date can cost a grand...

Dear Daniel, I promise I'll stop to tease you with so much out of topic queries any more. I've just figured out that is worthless, as it seems you avoid to answer anyway. Not that you are obliged to do that of course.

(ie): the "alternation of the skating force the tonearm can apply to the stylus/groove contact" that resulted by the twisting of the cartridge to the headshell, it does not seems a downside to me. And this is coming logically once the skating force isn't constant, we have to apply an antiskating force even to those pivoted tonearms that "apply practically zero skating force to the stylus" in order to fight this force across the whole length of the record groovies. So, it seems a neccessity and also inevitable to me as long as it is depended by the cartridge & the groovies also and not only by the tonearm. Now according to this logic, once that we have to integrate an antiskate mechanism to the tonearm, I can't see why the value of it could be in any way an indication of the tonearm's quality. We just have to apply more to those tonearms that carring a "twisted"?! cartridge on their headshells.

I'm really sorry but I just can't follow your replies, as in your posts it is impossible for me to find anything like an advice or a suggestion, no matter what the question is. I'm sure it must be a comprehension issue due to the combination of my bad English and my sciolism and so, I'm stopping right here with my apologies. Anyway thank you for your patience and your ability to stay calm with me for so long.

T Bone

I take on board all your points, and, as it happens, I agree with Dertonarm on some points. I just wish he would stop obfuscating and avoiding admitting he has completely missed the point on others.

Regarding reasons for different weighting, check out Keith Howard's piece in the features/reference section
http://www.stereophile.com

You said you couldn't get the numbers to match and something had to give. Something always does. In this case, the theoretical world. I never saw the point of giving numbers which were impractical for set up. Thirty years ago, no one set their tracking angle and the rest, to three decimals.No one does today. The numbers were rounded up for a nominal effective length of 230. The important word is "nominal". I should have perhaps laboured the point more, but that was back when tonearm geometry was perhaps better understood, and the issues concerning the choice of design - sliding vs fixed pivot, slots versus holes etc, were better appreciated.

How are you doing with the SME (or rather, sliding base) geometry? I'm going to post an explanation separately.

You said

Your point about 'just adjust angle and mounting distance as necessary' is EXACTLY right and appropriate given the imperfections we each bring to the table when we mount a tonearm/cart, but that is the art, not the science (and most of the critiques of Dertonarm's ideas and protractor on this thread are on the science, not the art, of tonearm setup, and his product I would think is specifically addressing ease of getting the art right - because the science is gotten right by anyone who gets the algebra right).

If his device makes setting up easier I'm all for it, but not if it is less accurate.

That was my reason for posting originally. He doesn't say what the accuracy of his device is, compared, for example, to a paper two point. Now I don't know how accurate a paper two point is, but I do know it is more accurate than the easier one point - two nulls are always better than one, as they allow an obvious a way of double checking. And in any case, as Dertonarm has said in the past:

But the alignment of the zero (points) is the raw basic on which everything else builds.

So, adding an arc in addition should certainly make it easier to set up (for a specific effective length) as the arc and the nulls must intersect, thus giving two opportunities to check offset.

I don't have a problem with that, I think it is a good idea.
If it is easier, great, fine, but is it more accurate...?

Hopefully, if not DerT, then someone will tell us.
J