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Mounting hole-to-stylus variation / tolerance

Hi all,
I know this particular point has been touched on, raised, in some of the threads dealing with tone-arm-alignment in particular.
I truly think it deservers a dedicated thread since it has a more or less profound influence on various arm designs and their alignment.
It also has a profound influence in how accurate and beneficial any after market alignment tool will work for you!

We have had this far, feed back from Jonathan Carr, i.e. the variations and tolerances with regard to his product (Lyra).
We also had some rather powerful insights by Frank ..., who designs and makes arms i.e. the variations of various products he took note of.

Jonathan quoted, that his current products have a +/- 0.3mm tolerance from the 'standard' IEC...? of 3/8" or 9.52mm.

The findings of some contributors are different, possibly due to simple variations much greater than 0.3mm (Lyra's tolerance) or possibly due to subsequent movement of the 'motor' relative to the body, caused by rough handling, re-tipping, etc.

It is of most importance to get more feedback on this, due to the dependence of a close match to 9.52mm, on arms such as ALL of SME, to name but one. These rely on this to be fairly accurately aligned. If not, some pretty unacceptable misalignment follows as a result, if the stock alignment method is used.

Lastly, HOW can a 'normal' end-user measure this distance with some degree of accuracy?
I have no problem using a vernier (calliper) and measure a +/- 0.05mm variation.
I can not see that this tool will be of use in this case. Optical measurement (like tool-shops use) will be best I should think --- but who, I ask, has this at hand?

Greetings,
Axel
axelwahl
axelwahl OP
788 posts
 
Tz, tz, tz, Daniel, I see what this is here.
Now don't tell us Herr Dr. Feickert is also part of the no discussion theme?

I met HIM promoting HIS player at the RMAF, and he had little time for the SME products, he resides way above such non-scientific aberrations, oh yes.
He has a following that tries to enlarge on Herr Schroeder's, so at least my impression.

Note: Everybody has to pay his rent :-)

Axel
jloveys
226 posts
 
Speaking of Dr. Feickert, doesn't his alignment device measures the exact distance between the needle and the pivot point ? This is the question of this thread isn'it ?
jloveys
226 posts
 
Question: I am building two different turntables with different platter diameters, different spindle diameter and want to use the same removable armboard with same tonearm, what is the best way to achieve the correct mounting hole/ needle distance and offset ?
Jean.
axelwahl OP
788 posts
 
Jloveys,
>>> Speaking of Dr. Feickert, doesn't his alignment device measures the exact distance between the needle and the pivot point ? This is the question of this thread isn’it ?<<<

Dr. Christian Feickert's device might do exactly as you say, but we are on about the shorter distance between stylus-point and the centre of the cartridge mounting-screw-holes.
All being equal (which it mostly is NOT) this aught to be 9,52mm or 3/8 of an inch.
This measure has of course a MAIN influence on the other measurement you ask about i.e. pivot centre-to-stylus point.
You might find a MAJOR discusion partner in "DerTonarm" (forum member's alias) to help you with your inquiry.
Take care,
Axel
Ag insider logo xs@2x
rauliruegas
13,021 posts
 
Dear Axel: +++++ " The maths is correct! But life seems to beat it all the time. " +++++

This statement is a confirmation of almost none serious/in-deep research ( laboratory one. ) on several/many audio item/device subjects not only on tonearm/cartridge subject.

The life seems to beat all the time because around science ( maths, physics, etc, etc. ) we don't " measure " what explain the subject, we " measure " in wrong place, we don't " measure " with all the factors involve, we don't make that " measure "/research in scientific and useful way, the maths can't know what each one like, the maths does not explain which kind and which distotions level are what we accept, the measures can't co-related to explain an overall audio subject, etc, etc.

The science/maths is a very wide " tool " that is very useful when is aplicate in the right way and when take in count all the different factors that can/could affect an event.

Do you think that the tonearm/cartridge resonance frequency matching ( calculation ) can explain why a cartridge/tonearm combination ( with normal moving mass and right set-up . ) can/could sound bad, I mean " so, so " ?, certainly not there are many factors involve to realy have a " light " that explain the " event ". Like this there are many examples, so we have to take the " science " where really help us like in the set-up stylus geometry. But even here each one has the free will to make what ever wants.

Regards and enjoy the music.
Raul.
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