Uni-Protractor Set tonearm alignment

Jazzgene, 'to bad Thorens ain't what it used to be'. I agree but there are many of those 'old one' second hand still demonstrating the value of simplicity in design: good platter, good bearing and an simple motor. Despite of
this fact the Uni-Pro on them looks to me like a King on
a donkey.

Regards,

Dertonarm:

You said:

If a phono protractor really is universal, it must automatically align regardless of the given mounting distance.

I would agree with you in that, but I would disagree with you when you say that

Setting the mounting distance is done before aligning the tonearm. It is a "conditio" already set before starting the alignment.

This is only necessary when using a protractor which requires it - like yours - because, as you say,

The UNI-Pro does follow the smart idea of Francis Dennesen and adapts to whatever P2S a given tonearm is mounted.

As is the case with the Dennesen, arms with adjustable bases and fixed headshell mounts are awkward for your protractor. So it can´t really be called universal, as it only caters for arms with adjustment for effective length and offset at the headshell.

In most cases the tonearm is already mounted when one starts to align the tonearm/cartridge

All arms are "mounted" prior to alignment, but, as you are aware, not all arms have the pivot to spindle distance fixed at a specific measurement, but have the facility to adjust this, as in any arm on a pod or adjustable arm board, or the SME, and arms like it.

It could be argued that a more universal version of the Dennesen would have adapted it to allow its use with arms such as these, as well as with different alignments.

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Raul,
Could you please elaborate on this? I don't understand what you are trying to do by moving the cartridge forward or backward. Are you asking us to listen for different amounts of distortion from a cartridge that is no longer aligned properly? Thanks.

Dertonarm:

you said

If however the user does wish to align the given tonearm exactly to the geometry (especially the offset angle) the tonearm was designed with, then knowing the P2S and setting it precisely (IF possible ...) is important.
Important only if one wants to avoid an additional breakdown torque and thus another source for skating force in a pivot tonearm with a fixed offset cartridge mounting.
With tonarms like the Schroeder, Reed or Talea however we won't run into this problem at all.

Didn´t you suggest starting an antiskate thread?

But since you have brought the subject up, in what way do the Reed, Talea and Schroeder differ from other arms?

The Talea and Schroeder appear to have a facility to alter the effective length,(as does any other arm with a slotted or movable headshell) and they have a facility to alter the headshell angle. What is the difference between this and altering the angle in a normal headshell?

The Reed has a normal slotted headshell except for the model with its little azimuth adjusting device.

What´s the difference? I would honestly like to know.

And I am intrigued to know what are these mysterious additional breakdown torques which the above arms don´t have.

Unless you can explain where else it comes from, the only torque acting to rotate the arm inwards is generated by forces acting on the stylus in reaction to downforce and friction. More downforce, more friction; more friction, more inwards torque. No downforce, no friction.; no friction, no torque.

Using more downforce doesn´t make the inwards force disappear, just that the force acting downwards is enough to allow the stylus to track without distorting. The imbalance of forces on inner and outer groove walls hasn´t gone.

John
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Dear John_gordon, you don't really want me to tell you what additional breakdown torque is and why it does of course influence the skating force.
If you think skating force is just a phenomenon of friction and downforce - fine, certainly no problem with me.
If you muse about the model and draw yourself a good and precise force vector model of a pivot tonearm, you'll figure out.
I did suggest starting a "antiskating thread" - I didn't say I want to start it nor did I say I want to participate in it.
I have no questions regarding skating force in tonearms.

Regarding the UNI-Protractor and it's "universal" use.
Apparently you haven't worked with it so far and haven't understand it's principle either. Otherwise none of the comments in your last two posts would have been made.
You won't find a pivot tonearm on this planet which you can't align with the UNI-Protractor to best possible performance and any desired tangential curve.
If you think you can do better - go ahead design it.
So far your comments have shown little more than poor judgement, a fairly high aggression and very little understanding of the subject.

I welcome your attempt to put your name on the wall again and to prepare the road for yourself for a soon-to-be return to the audio market.
No problem with me - as far as I am concerned you are certainly welcome.
I might react to a post by you from time to time only, but so far very few actually did ask for an answer or a comment. Most were simply lacking content and seriousness.