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Thread: web site for null points

  1. #1
    Join Date: May 2016

    Location: north wales uk

    Posts: 235
    I'm peter.

    Default web site for null points

    hi i have a DR F Protractor but it will not work on the sem 309 or any other sme come to think of it i have talked to Dr Chris Feickert who said it was SMEs fault and not his , you can use it for the pivot point but not the NUll points , or use it for the Null points and not the pivot point , so i was stuck , i was sent this web address that has the correct way to set the null points on sme arms and a great deal others ,

    http://www7a.biglobe.ne.jp/~yosh/armdata.htm

  2. #2
    Join Date: Jan 2009

    Location: Essex

    Posts: 18,433
    I'm openingabottleofwine.

    Default

    Quote Originally Posted by gwernaffield View Post
    hi i have a DR F Protractor but it will not work on the sem 309 or any other sme come to think of it i have talked to Dr Chris Feickert who said it was SMEs fault and not his , you can use it for the pivot point but not the NUll points , or use it for the Null points and not the pivot point , so i was stuck , i was sent this web address that has the correct way to set the null points on sme arms and a great deal others ,

    http://www7a.biglobe.ne.jp/~yosh/armdata.htm
    Why don't you use the protractor that comes with the SME arm, or use the null points quoted on the vinyengine.com arm data site?
    Have you listened to this month's choice in the Album Club?

    Barry

  3. #3
    Join Date: May 2016

    Location: north wales uk

    Posts: 235
    I'm peter.

    Default

    the protractor is incorrect you cannot get the pivot point as SME say , as there seems to be a difference on the web site and the manual for the pivot points , and you get too different responses from sme, i think it must be because the 309 is a removable head shell, and specifications have change over the years and mods to the arm itself ,also a lot of guess work with the sme protractor to drop the stylus into the little pin hole and then line either side up is just guess work , i have not looked at the ones on the vinyengine.com, i just thought the web site may be another source of information and be helpful to AOS members

  4. #4
    Join Date: May 2010

    Location: Dorset

    Posts: 2,822
    I'm John.

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    In all the years I have been using SME arms I never had any problems with their way of alignment. Perhaps you are over thinking things.

  5. #5
    Join Date: Jan 2009

    Location: Essex

    Posts: 18,433
    I'm openingabottleofwine.

    Default

    Quote Originally Posted by prestonchipfryer View Post
    In all the years I have been using SME arms I never had any problems with their way of alignment. Perhaps you are over thinking things.
    My experience exactly - I have five SME arms, and in all cases the setting up using the protractor supplied has been easy. Early SME arms were designed to follow the Stevenson geometry for minimum tracking error. Later ones had the overhang and offset changed slightly, so as to conform to the Baerwald geometry.

    I also have some arms where the offset and overhang are non-standard (Breuer Dynamic, Infinity 'Black Widow). In those cases I calculate where the null-radii should be, and mark them on a conventional alignment protractor. If the protractor points are correct to within +/-0.25mm, then the overhang will be correct to within +/-0.1mm.
    Have you listened to this month's choice in the Album Club?

    Barry

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