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Thread: Linear Tracking Turntables

  1. #16
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    It seems the skipping issue is now causing more problems. The TT is now booked in with a local AV expert who will service it and let me know of any potential trouble spots.

  2. #17
    Senior Member NoCoPilot's Avatar
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    Get those 'o'-rings ready...

  3. Likes Mark Dee liked this post
  4. #18
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    I did have a chat with him and we think it's one of the following:

    1. Old gunked up grease
    2. Loose or worn tone arm belt (although it's not really a belt, more of a string)
    3. Worn worm gear belts.
    4. This TT has a tracking position adjustment which takes its readings from the LED in the tone arm (when the tone arm moves inwards with the grooves the sensor is supposed to cover the LED which triggers the motor to move the arm inwards a fraction as the record is playing). I'm guessing if the sensor is faulty or wrongly adjusted the sensor thinks it has to move a lot more than it needs to, hence it suddenly lurches the tonearm towards the centre of the record.

    Watch this space.... until we can resume normal service, here is some music (on CD....)
    Last edited by Mark Dee; Mar-29-2021 at 16:06.

  5. #19
    Senior Member Baron Scarpia's Avatar
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    Quote Originally Posted by Mark Dee View Post
    I did have a chat with him and we think it's one of the following:

    1. Old gunked up grease
    2. Loose or worn tone arm belt (although it's not really a belt, more of a string)
    3. Worn worm gear belts.
    4. This TT has a tracking position adjustment which takes its readings from the LED in the tone arm (when the tone arm moves inwards with the grooves the sensor is supposed to cover the LED which triggers the motor to move the arm inwards a fraction as the record is playing). I'm guessing if the sensor is faulty or wrongly adjusted the sensor thinks it has to move a lot more than it needs to, hence it suddenly lurches the tonearm towards the centre of the record.

    Watch this space.... until we can resume normal service, here is some music (on CD....)
    Nowadays they could have made a mechanism that moved the tonearm with exquisite precision. If there is such a clunky mechanism for moving the tone arm, I would think it might harm, rather than improve, the tracking compared with a fixed pivot tonearm.
    There are two kinds of music, good music and the other kind. - Duke Ellington.

  6. #20
    Senior Member NoCoPilot's Avatar
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    Quote Originally Posted by Baron Scarpia View Post
    Nowadays they could have made a mechanism that moved the tonearm with exquisite precision. If there is such a clunky mechanism for moving the tone arm, I would think it might harm, rather than improve, the tracking compared with a fixed pivot tonearm.
    I've wondered about this too.

    Records vary in how far apart the grooves are -- depending on cutting volume and bass rolloff -- so there's no standard travel speed of a linear tone arm. Also 33s versus 45s.

    My SL-10s had an LED (as was mentioned above) so when the tone arm got a few degrees off parallel to the record, servo-motors caught it up. Theoretically this was not jerky, but a smooth steady travel across the platter.

    The SL-6 uses a simplified mechanism, where there are no servos, just a well-lubricated tone arm on a rotating shaft that follows the stylus as it tracks inward. This worked about equally as well as the servos, so long as your lubrication remained fresh.

    My Sony table I'm not quite sure what the mechanism is, because I haven't had occasion to disassemble it to that level yet, but I think it's servos again.

    I've seen all kinds of add-on linear arms for standard tables, and they all use servos so far as I can tell.
    Last edited by NoCoPilot; Mar-31-2021 at 16:50.

  7. #21
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    Got my Akai AP M313 back today after it was serviced. There are no drive belts on the tone arm - it uses a motor-driven worm gear and and a tracking sensor. Everything was lubed up and tested, and it seems to be playing very nicely so far.

  8. #22
    Senior Member NoCoPilot's Avatar
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    No belts? Sacre bleu!

    Enjoy the table Mark.

  9. #23
    Senior Member Simon Moon's Avatar
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    Quote Originally Posted by NoCoPilot View Post
    I've seen all kinds of add-on linear arms for standard tables, and they all use servos so far as I can tell.
    The best linear tracking arms, like the Airtangent you pictured above, like the name says, uses an air bearing, not servo controlled. The black "sleeve" where the arm shaft is mounted, rides on a thin cushion of air.

    Less successful are the servo controlled arms. Their problem is, they are always 'searching' for the best tracking, and the resulting sound, is that stereo images seem to shift slightly from side to side.

    The linear trackers that use belts to drive the arm, were easier and less expensive to implement, but probably have the most sonic compromise.

    Air bearings are best, but the hardest to implement, and to maintain. And the air pump has to be of very high quality, to maintain constant air pressure, and it has to be quiet.

    But, with the proliferation of 12" long arms, at relatively low prices (when compared to linear trackers), the positive attributes claimed for linear trackers (no IGD), have pretty much negated the need to linear trackers. I own a 12" arm, and the offset error is so small, that IGD is vanishingly small, and inaudible. Not to mention, there is no need for anti-skate settings.

    But, for those with the money, and the need to eliminate IGD completely, but without dealing with the problems with linear tracking arms, there is a whole new class of arms, that are pivotal, yet have zero tracking error. None of the finicky setup and maintenance of linear trackers, but all of their positive attributes.

    As you can see, this Thales arm is pivotal, but the 2 arm shafts slightly rotate the head shell as the arm is traversing across the LP, always staying in perfect tangential alignment. I have no question in my mind, that this tonearm implementation is the best design. I have not been able to see any downside (except the price, as they do tend to be expensive).



    Thales isn't the only company doing tangential arms this way, but they are the best known.
    And if there were a god, I think it very unlikely that he would have such an uneasy vanity as to be offended by those who doubt His existence - Russell

  10. #24
    Senior Member NoCoPilot's Avatar
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    Quote Originally Posted by Simon Moon View Post
    Less successful are the servo controlled arms. Their problem is, they are always 'searching' for the best tracking, and the resulting sound, is that stereo images seem to shift slightly from side to side.
    Why would you expect tiny adjustments at the far end of the arm to affect the other end of the arm, the one holding the stylus? Are you speculating the "stereo image shifting from side to side" would happen because the stylus isn't really seated in the groove?

    As a four decades long owner of linear arm turntables I can state I have never heard what you hypothesize would happen.

    Frankly, I'd be a lot more worried about the white noise from the air pump and escaping air from the black sleeve on that air-gapped arm

    Incidentally, the Thales isn't part of "a whole new class of arms." This is an ad from 1957:


    Garrard Zero-100 from 1970:
    Last edited by NoCoPilot; Today at 16:17.

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