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Cartridge Alignment to Protractor Extremes

Discussion in 'Audio Hardware' started by avanti1960, Apr 3, 2021.

  1. Brucedgoose

    Brucedgoose Forum Resident

    Location:
    Hawaii
    The Cart-Align system uses a mirror in the same way, which made it one of the best generic alignment tools. Ultimately not as good as the Mint Tractor because it wasn’t arm/table specific, but the mirrored sightline technique works really well to increase the apparent visual alignment as you adjust.
     
    Ingenieur and ghost rider like this.
  2. Love it!
     
  3. Sterling1

    Sterling1 Forum Resident

    Location:
    Louisville, KY
    I have easily achieved a 52mm stylus to headshell tail distance using the Technics gauge, confirmed with dial caliper and other aids to understanding the result of eyeballing which might be compromised from parallax if eyeballing is caviler.
     
    Big Blue, JackG and TheVinylAddict like this.
  4. Sterling1

    Sterling1 Forum Resident

    Location:
    Louisville, KY
    As best as I can discern from eyeballing via a line of sight on axis to plane at end of gauge, the stylus appears to be set at 52mm stylus to headshell tail distance. This picture does not communicate that condition very well because the camera lens distorts and is subject to parallax.[​IMG]
     
    Last edited: Apr 4, 2021
    JackG, TheVinylAddict and Ingenieur like this.
  5. TheVinylAddict

    TheVinylAddict ___The Enforcer___

    Thanks for taking the time to picture the easiest upgrade to the imperfect Technics gauge - a line on a piece of paper!!! ( I used words above, but a picture is worth a few more...)

    Easy peasy. And if you trust the engineers who designed the TT, that alignment sounds good too! Well, as long as you've also dialed in your VTA, TF, etc... :)
     
    JackG and Sterling1 like this.
  6. avanti1960

    avanti1960 Forum Resident Thread Starter

    Location:
    Chicago metro, USA
    first off it isnt much trouble. i line up the cartridge with the technics diving board then check it on the table with the mint protractor. usually just a few minor adjustments, especially lining up the cantilevr with the runway lines and it is right on the money.
    the margin of acceptable error depends on what kind of stylus profile you have. for some reason the cartridges i like are always particular about alignment.
    as for VTA with different thicknesses, the answer is no. i set it to a thick e.g. 180 gram flat pressing and leave it. the differences in thickness from thinnest to thickest vinyl changes the VTA angle tenths of a degree or so.
    alignment is more critical.
    if you get the alignment as close as possible, the stylus also wears more evenly. you want the tracking angle error, the twist of the stylus, to be of equal duration for the beginning of the LP outer grooves where the stylus is twisted counter clockwise in the groove- equal to the inner grooves where the stylus is twisted clockwise in the grooves.
    if the playing time for one of these condions is longer, the stylus will wear unevenly.
    again it is not too much trouble to use a good protractor.
     
    theMot likes this.
  7. avanti1960

    avanti1960 Forum Resident Thread Starter

    Location:
    Chicago metro, USA
    i tried this but the cartridge does not rest on the paper flat and even. also the headshell needs a little push and hold to compress the washer and fully seat in the gauge.
     
  8. Big Blue

    Big Blue Forum Resident

    Location:
    Wisconsin
    In terms of the plastic jig itself, I would agree, as it’s not the most precise tool, being made of plastic. However, using a digital calipers to confirm the overhang has always given me an alignment that is right on the arc of a protractor designed to match the Technics 1200 alignment geometry. Like, dead on, no questions.
     
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  9. Sterling1

    Sterling1 Forum Resident

    Location:
    Louisville, KY
    Yes, it does not rest on the paper flat. The gauge must be set on its base and then paper pasted to squared block which is eyeballed with eye positioned in plane of drawn line. The line is drawn to account for space from bottom of gauge base to headshell tail. That's it.
     
  10. Sterling1

    Sterling1 Forum Resident

    Location:
    Louisville, KY
    Here's the fast way to Technics alignment gauge perfection. Just draw a horizontal line at about 2.550 to 2.570 inches from bottom of paper. For exactness measure gauge with a dial caliper, or don't measure at all by placing gauge against paper to mark line points from which you draw a line. Then, fold paper as shown and place gauge next to it and position eyeball to axis of gauge "diving board" end plane. Move cart up or down to intersect drawn line. [​IMG]
     
    Last edited: Apr 5, 2021
    TheVinylAddict and Ingenieur like this.
  11. KT88

    KT88 Forum Resident

    The jig that comes with a new Technics deck is really just an overhang gauge. It isn't as accurate as a paper gauge as it has a couple of variables, most notably the distance from the stylus tip to the end point of the gauge. That allows for parallax error to skew the results. It is also only as good as the coupling of the headshell and headshell / arm assembly geometry in regards to both overhang and alignment. Azimuth is them a whole other issue with the moveable headshells. What the Technics gauge was designed to do was to get spherical cartridges to track evenly across the record and have a bit lower distortion at the end of a side than you would without setting it. it can also be used with elliptical stylus but you are relying on the cartridge assembly geometry to get the null point square, once you get the cartridge square in the headshell. That's tough with cartridges that don't have parallel edges. So really, it is referred to an overhang gauge as that is all it is.

    Using a protractor, you can get a much more accurate alignment and that is most critical with elliptical and more complex stylus shapes. Even the overhang setting will be more accurate when you can do that with the headshell mounted on the arm. It's intended to be a complete measurement of effective arm length, and the headshell is a part of the arm. That's what you are doing when using an arc protractor and by looking at that at the extremes of the arms travel. It keeps the stylus on that arc. Once you have set overhang, however you do it, then alignment to a pair of null points is important for lowest distortion either at the end of an Lp side, or averaged across the Lp side with that of course having some emphasis at the end due to the tracing distortion needing to be reduced the most there.

    Technics, and some other Japanese makers generally used a shorter effective arm length and thus less overhang. This results in many cartridges being mounted farther back in the headshell than some other alignment geometries. Perhaps the most popular newer alignment is the Baerwald, which optimizes the cartridge for an averaged low distortion across the Lp side. This alignment will have the cartridge near the end of the headshell mounting area, and some arms and cartridges cannot even be set to this due to the lack of length of the arm. Using whatever protractor that you choose to use will allow the best alignment that you can achieve on it by allowing you to align the actual cantilever and stylus while it is attached and in playing position on the tonearm.
    -Bill
     
    Sterling1 likes this.
  12. KT88

    KT88 Forum Resident

    Ha! I use paper. Any material is more accurate than your eyesight, which is the real limiting factor. That, and your patience. ;)
    -Bill
     
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  13. KT88

    KT88 Forum Resident

    That's what I use on every alignment job.
    :nauga:
    -Bill
     
    TheVinylAddict likes this.
  14. Sterling1

    Sterling1 Forum Resident

    Location:
    Louisville, KY
    As a long range US Service Rifle shooter I know for sure eyesight can be a limiting factor but eyesight can balance and center things with astonishing accuracy. And knowledge of the angular error caused by sighting misalignment can eliminate parallax error entirely. Interesting stuff.
     
  15. MattHooper

    MattHooper Forum Resident

    Location:
    Canada
    I received my mint protractor a while back. Been raring to us it, except I've been experiencing miserable problems with my system, from vinyl playback distortion that took forever to diagnose, to having to get a new cartridge, to then having distortion elsewhere in my system, diagnosing that, re-tubing my amps, my amps continuing to blow tubes and fuses...it's been months of this. I'm dying to listen to records again!
     
    avanti1960 likes this.
  16. Brucedgoose

    Brucedgoose Forum Resident

    Location:
    Hawaii
    Yes, the cartridge and headshell must be attached to the arm when you do your alignment or you’ll likely introduce errors when you attach the headshell to the arm.

    Paper can be accurate in this application if there’s only a single sight line involved since dimensional changes won’t impact that single line. Paper gauges with null points can’t be as accurate as metal gauges because the null point markings themselves will move slightly with temp/humidity changes. Coated paper is better, but still not as good as aluminum. I generally would shy away from a piece of paper folded and freestanding in the wind, because that looks inherently unstable to me. But I acknowledge that a single line drawn by hand on a piece of paper can work. Keep the windows closed to keep out the breeze! Never fly in any seriously precise application, tho’.
     
  17. StratDoc

    StratDoc Active Member

    Location:
    Chattanooga, TN
    I have learned a lot from reading this thread - good information.

    What would be the measurement refence points if the head shell does not detach from the tonearm, like on my Proj-Ject X1 table? I use the db systems alignment protractor to align the cartridge but have never measured overhang.
     
  18. Davey

    Davey the blue of distance

    Location:
    SF Bay Area, USA
    For the Pro-Ject, the overhang is specified at 18.5 mm and effective length at 218.5 mm, so pivot to spindle distance is 200 mm. You can use the Conrad Hoffman utility to generate an arc protractor like below, with Lofgren B/DIN selected if you want to match the Pro-Ject specs. Overhang is set correctly when the stylus traces the arc from outside to inside without moving the protractor. But alternately, you can just measure it, the stylus should overhang the spindle centerline by 18.5 mm. Or you can measure the pivot to stylus distance, which should be 218.5 mm ....


    [​IMG]
     
    KT88 likes this.
  19. KT88

    KT88 Forum Resident

    @Davey just gave you the complete run down. In short, you can just continue to use your protractor though, if you like. Knowing the overhang spec is good, as once set, it is just a matter of rotating the cartridge body a bit to get the stylus to fall in line with your protractor. You don't need the arc, or even overhang measurements but they do make it faster and easier. If you can align precisely at both null points using your protractor, then over hang should fall into place.
    -Bill
     
  20. KT88

    KT88 Forum Resident

    Yep, eyesight is more accurate than many give it credit, when you know how to view something and verify it by being able to repeat it. I don't recall the percent of a degree, but it's close enough that it works well. What people need to understand is that no matter how close you get it, it's always a moving target in use, as the records are never perfect either. At some point you need to stop fretting over measurements and methods and start listening to music.
    :cheers:
    -Bill
     
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  21. KT88

    KT88 Forum Resident

    Well, I haven't seen my lines move since I printed them. I can't get them any thinner or get the paper any flatter. It'll never be perfect, but it gets the job done nicely and without too much fuss.
    -Bill
     
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  22. StratDoc

    StratDoc Active Member

    Location:
    Chattanooga, TN
    Since I have set the alignment properly for the cartridge using the protractor, there is no need to worry about over hang as it will be correct or close to correct?
     
  23. Davey

    Davey the blue of distance

    Location:
    SF Bay Area, USA
    That's correct, you can't be perfectly aligned at both null points if the overhang or offset is incorrect. It just takes a lot of back and forth to get there, and care in the sighting of the cantilever to the grid to assure that accuracy since the overhang can be a ways off and still almost look aligned on the null point grids. The arc protractor just makes it a little easier and faster since it separates the overhang and offset adjustments.
     
  24. StratDoc

    StratDoc Active Member

    Location:
    Chattanooga, TN
    Must confess I am a bit confused by this. Printed a template using the tool and specs provided. Center circle is cutout and goes on the spindle? The radius of the template doesn't appear to long enough to work - distance from spindle to alignment grid is too short.
     
  25. Davey

    Davey the blue of distance

    Location:
    SF Bay Area, USA
    Well, not exactly clear to me what you mean, presumably you printed a full size version from the tool and verified the scale markings on the edges to assure it printed the correct size?

    Usage is like below, hole over spindle and overhang adjusted to follow arc, then offset adjusted at one of the null point grids ...

    [​IMG]

    [​IMG]

    [​IMG]
     
    Last edited: Apr 5, 2021
    Mister Charlie likes this.

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