Which protractor for an AT1120

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elreza
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Which protractor for an AT1120

Post by elreza » 14 Jan 2020 08:25

Could someone tell me which protactor I should use for an AT1120, is it just down to how much I set the stylus overhang to as it seems to infer on this page ? please and thanks

https://www.vinylengine.com/tonearm_ali ... =calculate

blekenbleu
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Re: Which protractor for an AT1120

Post by blekenbleu » 21 Jan 2020 18:09

If tonearm and headshell have perfect geometry (which an AT 1120 presumably has)
and cartridge cantilever alignment within the headshell is perfect,
then stylus overhang is indeed one way to complete cartridge alignment.

Some folks want a so-called arc protractor, which requires:
  • precise knowledge of pivot-to-spindle distance to accurately generate
  • confidence that a generated PDF is printed with exactly 100% scaling
Arc protractors can simplify confirming stylus overhang,
provided that the stylus is visible, which is not always true.

An alternative (and my preference) are a simple "strip" protractors
with spindle hole and alignment grids at desired tracing error null points.
These do not depend on pivot-to-spindle distance
and verify cartridge alignment independently of tonearm and headshell geometry.
The remaining variable is preferred null points locations e.g. Baerwald, Loefgren or Stevenson.
https://www.vinylengine.com/protractor-user-guide.shtml

Potential strip protractor issues:
  • some such protractors have relatively crappy alignment grids
  • some headshells (e.g. Ortofon G-shells) confound visually confirming cartridge body alignment
  • some cartridges (e.g. many moving coils) obscure stylus alignment with those grids

elreza
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Re: Which protractor for an AT1120

Post by elreza » 23 Jan 2020 09:55

thanks so basically I can, using a strip protractor, use any of Baerwald, Loefgren or Stevenson dependent on my distortion preferences

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