Where to find uni din protractor

Hi dear John, What a pleasure to read the lecture of a real
professional. I have no idea about possible deviation of the
different spindle thickness by different turntables. Yip
consider them as important for the precision of his Mint
tractor. But he sells them so 'some objective' info looks
also important. Will you be so kind to explain the issue?

Tawa, Google for 'Arche headshell' or 'Archon MC cartridge'
to find all Dertonarms inventions.

Hi Nikola,

Some more boring stuff...

There is an RIAA standard from 1963 (and subsequent later revisions and metrications) which gives the record hole size as 0.286", with a tolerance of +0.001" and -0.002". This means that the hole can be between 0.284 and 0.287 (7.214mm to 7.289mm).

Why should this be? It seems a strange size until you remember that the standard was established in the age of imperial sizes, and the nearest fractional size is 9/32" which is 0.281" (7.14mm). This would have been the nominal size for a spindle, and the records were made to fit neatly on a typical spindle, not vice versa.

If a spindle diameter had been within the range for hole size, the record will be a push fit or an interference fit. It won't drop on or lift off easily.

The spindle should probably ideally be 0.282 +0 and -0.002 (7.11mm to 7.18mm)

From a quick internet survey of measured spindles, typical modern spindle sizes are around 7.1 to 7.2mm ie 0.279" to 0.283". In other words 9/32" +/- 0.002", which might be expected.

So, with regard to protractors, these are small amounts and the effect on set up is minuscule regarding the position of the nulls if the error in position is in that direction - variations in distortion in the hundredths of a percent (ie 0.01%)

For a protractor that uses the Dennesen principle, like the Smartractor/Unitractor, any variation in the overhang direction of 0.1mm would produce an error in offset angle in the order of 0.08 degrees, which, depending on the direction of the overhang variation, can actually reduce average distortion for a Lofgren A IEC alignment.

However all these numbers are tiny and bear no relation to the variation in accuracy normally achieved in practice (with whichever alignment). Usually the overhang is easiest to set and both the Mint and the Uni protractor, make much of how accurately their items are made, to within 0.01mm. So perhaps if you have an arm with a micrometer adjustment for overhang you could perhaps work to those tolerances with patience and time.

However, the restricting factor is usually how accurately the offset can be set, especially on an arm where adjusting the offset also affects overhang. If you get within a tenth of a degree you are an ace. Worrying about hundredths is silly.

Best wishes to you and all Audiogoners for 2015.
John
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Why would anyone recommend Dertonearm, Dietrich Brakemeier,
Acoustical Systems.de Arche headshell.de
Even a casual user of AudioGon over the past couple of years could of
very well read about the fraud Brakemeier committed not only here on
AudioGon but elsewhere, So for frequent members this should be common
knowledge the guy is bad news.

Dertonearm is banned due to committing Fraud and I know of a well
respected member that was defrauded out of thousands of dollars and
subsequently I was made aware of others in this audio community that
were defrauded out of much more , into the tens of thousands of dollars
,.....

Dertonearm received money for product that he never delivered, down
payments sent for expensive custom items never built and refund promises
for many other audio related items that remain unfulfilled , it goes on and
on to the tune of many tens of thousands of dollars ,

So knowing this why would anyone promote this low life thief ,......

In-shore, Well to me J. Carr is the nicest person in our
forum but this quality of his character would not be a
sufficient reason for me to buy his carts. It is rather the
other way round. The quality of his carts will be the real
reason to buy them. Because of Lew I am reluctant to mention
Newton who was very nasty as person. He even accused Leibniz
to have stolen his infinitesimal calculus. I don't believe
that mathematicians and phisicist refused his calculus
because of his character.
The mentioned Dertonarm's products are sold by a dealer
and not by him personaly. If whomever thinks that his Arche
or Protractor is the best there is one is entitled to buy
them for the simple reason that we all are free to spend our
money as we like. I would never dream to ask In-shore what
I should or not buy.

Natdric ,You may have invested money into dertonearm to come
up with such ridiculous and comical response , to defend / suggest others
to do business with this clown is pretty low., but that doesn't surprise me of
someone of your caritor ie lawyer.