Technics cartridge alignment discrepancy.

Discussion in 'Audio Hardware' started by aunitedlemon, Mar 27, 2023.

  1. aunitedlemon

    aunitedlemon Unity is in the pith. Thread Starter

    Location:
    Oregon
    This is a carry over from a conversation I began in the Technics general thread. There's been a good amount of conversation and brainstorming regarding a cartridge alignment discrepancy I first noticed after purchasing a Vinyl Source arc protractor. That thread derailment began here- The Technics SL-1200 GAE/G/GR general questions thread

    In summary, when I align my stylus tip to the target mark on the plastic Technics overhang gauge my stylus cannot trace the appropriate arc of the protractor designed around the Technics specific null points w/o having to rotate the cartridge (towards the spindle) in the headshell. If I keep the cartridge square within the headshell (as Technics specifies one should), and align the stylus to accurately trace the arc of the protractor, cartridges have to be nearly all the way back towards the bayonet in the headshell mounting slots. The question is, why don't the plastic Technics jig and the Technics specific arc protractor confirm one another on my SL-1210GAE?
     
    theMot likes this.
  2. aunitedlemon

    aunitedlemon Unity is in the pith. Thread Starter

    Location:
    Oregon
    Regurgitating subject material previously posted in the general thread for the sake of illustrating the discrepancy w/in this topic specific thread.

    Prepping the GAE w/ a printed arc protractor.
    [​IMG]

    Starting w/ the overhang jig here,
    [​IMG]

    The stylus lands well ahead of the arc near the spindle.
    [​IMG]

    Sliding the cartridge all the way back in the rails, the stylus follows the arc and hits the null points much more satisfactorily.
    [​IMG] [​IMG]
     
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  3. aunitedlemon

    aunitedlemon Unity is in the pith. Thread Starter

    Location:
    Oregon
    Now w/ the stylus properly tracing the arc of the protractor it looks like this aboard the jig.
    [​IMG]

    The cartridge is slammed to the back of the headshell w/ this alignment.
    [​IMG]

    I've aligned four cartridges to four separate headshells, cross-referenced three different Technics overhang jigs and two different arc protractors and my results are consistent.
    [​IMG]
    Either I am consistently screwing up or there actually is an underlying "error".
    Thoughts?
     
    Last edited: Mar 27, 2023
    bluemooze likes this.
  4. Ingenieur

    Ingenieur Just a dog looking for a home...

    Location:
    Back in PA
    First
    Your mat is concave
    That may throw it off
    Try without the mat or oem mat

    with the Technics 52 mm does it hit the outer null?
     
  5. Davey

    Davey NP: CLARAGUILAR ~ Figura (2024)

    Location:
    SF Bay Area, USA
    The trouble is you left all the resulting pages of conversation in the other thread, presumably you are just looking for fresh insight? :)
     
  6. ubiknik

    ubiknik Forum Resident

    Location:
    Chicago, IL USA
    The Technics SL-1200 GAE/G/GR general questions thread
    That link goes to my recent post about it.

    This pic shows the plastic VS protractor:
    [​IMG]
    Unlike the paper printed version this gives no sight line to the tonearm pivot, but I guess you are supposed to get the stylus to trace the arc which sets the overhang, then keeping it in place you check the null alignments.
     
    BZ58 and aunitedlemon like this.
  7. aunitedlemon

    aunitedlemon Unity is in the pith. Thread Starter

    Location:
    Oregon
    I don't think the 1 mm concave of the mat from edge to spindle is causing this issue but it's a valid point worth considering.
    So if I start at 52mm via the jig, and rotate the protractor to begin at the outer null, then the stylus lands ahead of the arc as it heads towards the spindle. If I set up the protractor via the spindle to pivot string line, the stylus is ahead of the arc at all times. I theorized my arm tube is somehow too long but haven't been able to verify that's the case.
    I was just making an attempt to give this ongoing conversation it's own home. Not sure how I would've migrated all of the bits of conversation over to this thread. That's kind of why I hot linked my initial post on the subject at the beginning of the conversation to leave it up to others if they want to read through it and join the conversation.
     
    The FRiNgE likes this.
  8. lsipes1965

    lsipes1965 Forum Resident

    Location:
    Ky
    As soon as I found the Technics jig years ago I lost every protractor I ever had. Why bother? And how do you know there aren’t printer distortions? I’ve never had any issues using the jig. Every upgrade in cartridge I’ve made in the last 2 years has been readily heard just using the jig and following cartridge maker instructions. Matter of fact, now that I think about it…..the last Grado I had was the only one I ever saw do the Grado dance…….Using a freaking protractor. Throw it away and get on with your life is my advice.
     
  9. Ingenieur

    Ingenieur Just a dog looking for a home...

    Location:
    Back in PA
    If you want try this
    Set to 52 using Technics
    Using the black template set the stylus 1/2 between null points
    It should be ~86 mm from spindle
    See if it hits both null points now.
     
  10. Davey

    Davey NP: CLARAGUILAR ~ Figura (2024)

    Location:
    SF Bay Area, USA
    I understand why you did it, but I think you will just have to go over all the discussion again here, as evidenced in the post above from Isipes1965 :)
     
    aunitedlemon likes this.
  11. theMot

    theMot Forum Resident

    Location:
    Sydney
    I’m willing to be converted but my thinking is honestly along the same line. Like i said in the other thread, the cost for Technics to provide a protractor instead of the gauge would be negligible. Why would they sell a TT for thousands like the G model and not supply it with a protractor if required?
     
  12. Davey

    Davey NP: CLARAGUILAR ~ Figura (2024)

    Location:
    SF Bay Area, USA
    I don't think this thread was really intended to be about whether a protractor is required to get a good alignment, it is about the discrepancy in this one table. The Technics gauge seems to produce the wrong alignment, the effective length is about 2mm or so too long compared to the protractor arc, which measures the correct 230mm from pivot to arc. It would seem the tonearm tube is too long, but that potential discrepancy hasn't yet been verified.
     
    OldandBroken and aunitedlemon like this.
  13. ubiknik

    ubiknik Forum Resident

    Location:
    Chicago, IL USA
    The protractor you got is supposed to be the same alignment as using the jig, so if they don't agree then something is causing that to happen, either the arm is too long or the newer protractor is wrong somehow.
    The Technics jig works amazingly well as long as the arm is the correct length, if the arm is off and the protractor is correct then you just have to use the protractor and all is well because the jig can't correct an arm that is too long.
     
  14. aunitedlemon

    aunitedlemon Unity is in the pith. Thread Starter

    Location:
    Oregon
    There's a 150 mm reference line printed on the protractor to verify it's printed to the proper scale
    Throw what away? The jig? The protractor? The turntable? The baby and the bath water?
    These are the details I enjoy in life and found it interesting that there's a discrepancy between the jig and arc protractors. I'll keep on keeping on and you be you.
     
    oregonalex and Doc Diego like this.
  15. B_a_R

    B_a_R Forum Resident

    Location:
    Oakland, CA
    Ahh the cart alignment woes.. Read through a bit of the last thread and this one. If you're planning on keeping that TT for any length of time i HIGHLY suggest ordering a Mint from this guy: Best Tractor / Arc Protractor / Mint Tractor / tonearm alignment / Yip Mint Protractor / Mintlp Protractor . It's the most accurate protractor i've ever used. He custom makes them to your spindle size and tonearm pivot to spindle distance, so if you're using that table and setting up multiple carts regularly, it's great. The Dr Feikert system is nice too, more universal for different tables, but the lines he prints on the plastic disc are pretty fat and that CAN make a difference. Not sure what your budget is but it was one of the best investment for set up i've ever made. On that last photo of the old thread the birds-eye shot, looks like the front of the cart could use a little clockwise twist to align the Zenith.. unless that protractor lets you look head on and align via the cantilever to the grid. I have a few carts that need to be almost all the way FORWARD in a headshell, also needing some twisting to get the Zenith right. Headshell/Tonearm end angles arent always spot on but as long as there's room in the slots to twist for zenith it'll (hopefully) line up... Just my 2 cents...
     
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  16. haz2000

    haz2000 Forum Resident

    Location:
    nowhere
    Here is my photo having the same protractor. I don't know if this is helpful. If you like I could try to take another photo.

    [​IMG]
     
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  17. aunitedlemon

    aunitedlemon Unity is in the pith. Thread Starter

    Location:
    Oregon
    Thanks. You're using the Vinyl Source protractor? I think your stylus looks a little shy of the intended target overhang mark too. Very similar to my own results.
     
  18. haz2000

    haz2000 Forum Resident

    Location:
    nowhere
    Correct! but I did use the regular mat and not the concave one (But I own that mat, too)
     
  19. haz2000

    haz2000 Forum Resident

    Location:
    nowhere
    Would the Feikert work on a Technics? It doesn't have the Technics alignment.
     
  20. Ingenieur

    Ingenieur Just a dog looking for a home...

    Location:
    Back in PA
    Where do the screws sit in the slots?
    Thnx
     
  21. ubiknik

    ubiknik Forum Resident

    Location:
    Chicago, IL USA
    I have a Mint and yes they are very good but the Vinyl Source protractor is basically the same idea, it just uses a plastic substrate with printing as opposed to a decal applied to a piece of mirror.
    It's not a custom geometry, it's supposed to give the same geometry that the manufacturer intended and what you usually get when using the OEM jig.

    And since there is a discrepancy between the two we are trying to figure this out.
     
    Last edited: Mar 27, 2023
  22. ubiknik

    ubiknik Forum Resident

    Location:
    Chicago, IL USA
    3 and counting at this point.
     
    punkmusick likes this.
  23. ubiknik

    ubiknik Forum Resident

    Location:
    Chicago, IL USA
    I like your thinking here, I hope he tries it.
    Realistically though he's been through that process a couple times and has no problem hitting the null points or arc.
    It's just that the result doesn't match up like it's supposed to.
    More and more I can't help but think that this VS protractor might be giving a different geometry than what the Technics jig does -but the numbers printed on it say it's the same geometry as the jig.
     
  24. Davey

    Davey NP: CLARAGUILAR ~ Figura (2024)

    Location:
    SF Bay Area, USA
    Maybe. The only one I've seen post a measurement of the tonearm pivot to protractor arc (effective length) was the OP. Not sure how many users have the ability to make an accurate measurement to verify the effective tonearm length and know whether the Technics jig or the protractor is correct.
     
  25. Boltman92124

    Boltman92124 Go Padres!!

    Location:
    San Diego
    You're not crazy. Just remember that most of the protractors out there do NOT match the Technics jig. Especially Lofgren and Baerwald. Even the Stevenson I tried (Hoffman DIN) was not a match on the ARC. Rule of thumb is-Use one or the other. And, of course, make sure the numbers and printing of the protractors is correct. And it is not unusual to have the offset angle of the cartridge angled in towards the spindle using some protractors. It is perfectly normal.

    If you're 100% sure you've got a spot on protractor, try both and see what sounds better. Especially compare inner groove performance.

    I'm lazy these days with a microline cart. Technics jig and done. No IGD issues.
     
    Last edited: Mar 27, 2023

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