and yet you continue to respond. Very entertaining. I take it it's time for libations.
This is beyond the scope of our discussion.
It is probably true for servo-driven linear tracking arms. The arm moves in steps. For poorly designed mechanical linear arms, the arms may move in steps as well, but not for well-designed mechanical linear arms. Anyway, I am not a fan of the traditional servo-driven arms. Warrjon is working on a servo-driven linear arm now. It is basically a pivot arm on a moving platform. It may reduce the tracking errors and stylus drags caused by traditional servo-driven linear arms.
DIY Servo driven Linear tonearm
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A turntable is in principle a very simple device; it has to turn the record at a constant rotational speed and it has to hold the cartridge perpendicular to the playback groove. Yet doing these things is elusively difficult to achieve with the consistency and precision required so as not to detract from the quality of audio reproduction.
If there was one correct way of achieving these requirements, everyone would be doing it and there wouldn't be any argument or discussion about how to do it. The challenge is not helped by the fact that records are not perfectly round or perfectly flat.
This thread started about alignment protractors for pivoting tonearms and was highjacked by a proponent of linear tracking tonearms, without any acknowledgement that a different approach to holding the cartridge in perfect position over the groove simply has a different set of compromises.
In my experience alternative design approaches can be refined to achieve a very musical set of compromises, if the limitations are acknowledged and mitigated.
In the hundreds of turntables I have serviced, I have yet to receive one that was optimally aligned, whether brand new out of a box or a treasured possession from a hifi enthusiast, whether a pivoting or linear tracking tonearm.
Do you have any example of brands / models that exactly fulfill this task?
As you know, there are several forms of AS, for example, by hanging weight or tilting weight, magnetic, spring, etc. But I can't imagine how, once a certain setting is selected on any of them, the AS - selectable only by the weight of the chosen cartridge - will then automatically adjust as the arm moves from the outside to the inside of the vinyl.
The tangential error will constantly change! , I don't see a way that a purely mechanical system can "guess" that ... I think they are only approximate calculations from the manufacturer, as you said.
I examined - with 60 X magnification - the diamond of a needle and it was unevenly worn (I don't remember now which side it was + or - wear, for that matter it is the same) although the AS had been adjusted according to the manufacturer's recommendations.
The weight and thread system does create an antiskating force that varies as the tonearm moves across the record. This is due to the varying angle of the stub that the thread attaches to on the tonearm and the position of the thread's pivot point changes the mechanical advantage of the mechanism. It is important to make sure the wire loop or pulley is correctly positioned relative to the tonearm and the platter centre so that the variation in antiskating follows the intended design.
There are some problems with a string and weight antiskating device. Friction or stiction at the pivot point causes the antiskating force to modulate on eccentric records because of innate hysteresis. I always carefully clean the nylon thread and lubricate it with some silicone oil, wiped off with a rag, and clean the loop or pulley and bearing. If the thread has become stiff, it needs to be replaced with a new piece.
The pendulum behaviour of the weight also modulates the antiskating force. Pendulum motion can be set off just by moving the tonearm, particularly with sprung suspension turntables like Linn, Thorrens, Ariston, Lenco, etc.
Tilting weights also change the force relative to arm position as the effective length of the two levers changes at their contact point, changing the mechanical advantage of the levers. As well, the weight moves closer and further from the pivot axis and decreases or increases it's contribution to the antiskating force. Properly design this works quite well, but these systems are not friction free, either.
Spring based antiskating compensation also compensates for the angular position of the tonearm because the spring acts against a cam that is shaped to generate the correct force as the angle of the tonearm varies. Spring and cam compensators can and do drift out of calibration over time and are quite fiddly to get back in to calibration. They also have some friction in the mechanism.
Some tonearms, such as the Rega and all of its derivatives, use a magnet based antiskating system. In this system a magnetic shield moving with the tonearm determines how the antiskating force from a fixed magnet is varied by the tonearm position. The amount of antiskating is set by adjusting the position of the fixed magnet. The beauty of this system is no hysteresis and no friction.
Lower price turntables often have poorly designed and/or calibrated antiskating compensators; more expensive turntables tend to be much better, but that is only a generalisation! I always do static and dynamic tests at different radii to confirm the antiskating is set and working correctly.
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The first AS magnet system that I remember was implemented by Thorens if I remember correctly ......
Do you have experience with the AS of Micro Seiki's MA707?
I remember that years ago I had to extract the arm from the plinth, to supplement it because the arm was not parallel to it, which gave a negative VTA (something strange for being a prestigious manufacturer) and I observed that it has a spring inside, I do not remember others details.
But I always had the doubt if from that moment it could not have been "decalibrated" with my intervention ...
Micro Seiki MA-707 Dynamic-Balance Gimbal Bearing Tonearm Manual | Vinyl Engine
Do you have experience with the AS of Micro Seiki's MA707?
I remember that years ago I had to extract the arm from the plinth, to supplement it because the arm was not parallel to it, which gave a negative VTA (something strange for being a prestigious manufacturer) and I observed that it has a spring inside, I do not remember others details.
But I always had the doubt if from that moment it could not have been "decalibrated" with my intervention ...
Micro Seiki MA-707 Dynamic-Balance Gimbal Bearing Tonearm Manual | Vinyl Engine
United Audio/Dual implimented a novel form of antiskate in it's better record changers and turntables.
It used a spring system along with a swinging lever, relatively simple, that actually changed tension as the tonearm moved towards the spindle.
The German technology of Duals was first class and light years ahead of other manufacturers.
Garrard had a weighted lever system, a bit crude to Duals, and the as the lever was moved by the tonearm, the weight's tension on the lever changed due to its position relative to the fulcrum of the lever.
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No, I haven't worked on one of those tonearms.
Interestingly the service manual says the antiskating is spring based, but the spring mechanism doesn't appear in the service manual's exploded diagram or parts list.
In the service manual it says:
Establishment of the anti-skating force:
Relative to needle pressure
That is obvious, but it has made me think that my AS system is not affected, but that the error is mine when using smooth surfaces (RX or adjustment vinyls) to achieve that the arm is "static" on a certain surface, which by I usually choose in the final sector where there is distortion of internal grooves. In other words, those who say that it is not a good method are right, there is an excess of slip there that is not the same as there would be if the needle is in the groove!
I'll go back to the original setting that marks the arm, and listen a bit. You always learn something new !
Establishment of the anti-skating force:
Relative to needle pressure
That is obvious, but it has made me think that my AS system is not affected, but that the error is mine when using smooth surfaces (RX or adjustment vinyls) to achieve that the arm is "static" on a certain surface, which by I usually choose in the final sector where there is distortion of internal grooves. In other words, those who say that it is not a good method are right, there is an excess of slip there that is not the same as there would be if the needle is in the groove!
I'll go back to the original setting that marks the arm, and listen a bit. You always learn something new !
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Yes, the Dual turntables were excellent, but the tonearms were too weak, highly compliant, though.
A guy once picked up the turntable with his arm locked just to drag it away from his location, and he twisted it ...
If you get the HiFi News test record (HFN 002 Review - HiFi News Test Record | Vinyl Engine) there are twin tone antiskating bands at the outer, middle and inner radii on side 2, so you can check if the antiskating is correct across the record. There is also a blank 'land' sector for a static test of antiskating on side one, plus four tracks of twin tone test track at increasing levels as the last tracks.
If you wear headphones, it is very easy to 'tune' the antiskating force as the buzz sound moves from one side of your head to the other as you move from too much to too little or visa versa; it's tuned when it's in the middle.
If the static test on the 'land' band is radically out after you have tuned the antiskating on the dynamic twin tone test tracks, then I suspect something is wrong with the alignment. Assuming the overhang has been set correctly with a two point protractor the top contenders are stylus azimuth and perpendicularity of the stylus tip.
To adjust the azimuth there is a L+R noise band on the record. If you are able to subtract one channel from the other (I use a KAB Stereo Canceller for this KAB GREAT SOUND ESCORT STEREO CANCELER AT KABUSA.COM) then you can adjust the azimuth for the lowest output, which occurs when the azimuth is correct and the two channels are closely balanced.
If you don't have the ability to subtract one channel from the other, there are two bands that are noise on L, and noise on R channels, respectively. To use these tracks play the left track, but listen to the right channel only, then play the right track and listen to the left channel only. If they sound the same, great; if one is louder than the other, the azimuth is out. Adjust the headshell rotation (looking at the axis from the front) until you are able to get the two channels to sound the same and be at the same (hopefully) very low level. How low is a function of the cartridge's similarity between left and right channel responses.
To check the perpendicularity of the stylus tip you can use a microscope. There are inexpensive USB scopes that are suitable. Alternatively, listening through headphone to the 2-channel noise track, the sound is 'focussed' when the perpendicularity is correct and the two sides of the stylus are contacting the two side of the groove in phase. This track is recorded around the outer tracking null so tracking error doesn't affect the result. To adjust the perpendicularity rotate the cartridge slightly in or out around its vertical axis without changing the overhang until you find the sweet spot. The cartridge may end up not being parallel to the headshell if stylus tip was not perpendicular to the centreline of the cartridge.
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Knowing the weight of those Dual machines, using the tonearm for a handle is utterly stupid and abusive.
So no, those tonearms were not weak, the brain of that person was weak. 😉
......the brain of that person was weak.
I agree, although I will say in his defense that that person was not well educated about the delicate things that were available to him. Sometimes happens.
He wanted to clean underneath the Dual and he ran it from place taking it with one hand underneath and with the other hand taking the arm, the TT was unfortunately with the cover raised and the arm locked, suppose that he will have noticed something firm ...
It was a Dual 1219, if I remember correctly.
I agree, although I will say in his defense that that person was not well educated about the delicate things that were available to him. Sometimes happens.
He wanted to clean underneath the Dual and he ran it from place taking it with one hand underneath and with the other hand taking the arm, the TT was unfortunately with the cover raised and the arm locked, suppose that he will have noticed something firm ...
It was a Dual 1219, if I remember correctly.
Thank you for such complete and detailed information, again I appreciate it very much.
But I think it will not be necessary to go for those vinyls to line up an Orthophone 2M Red.
I have a test and calibration disc from Nautilus Records, but I don't understand fluent English and never pay too much attention to it, I only used it for the " flat" part and checking the AS.
Anyway, today I'll see if I hear any audible differences between the manufacturer's factory AS alignment and the sector "flat" vinyl / RX plate trimmed.
I see it unlikely.
Attachments
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johnmath :
I just finished doing the "study" about the functioning of the AS of my tone arm (I opened another thread, I don't want to kidnap this one)
https://www.diyaudio.com/forums/ana...ccurate-anti-skating-systems.html#post6683803
I just finished doing the "study" about the functioning of the AS of my tone arm (I opened another thread, I don't want to kidnap this one)
https://www.diyaudio.com/forums/ana...ccurate-anti-skating-systems.html#post6683803
Back to the topic.
If you want to align your cartridge correctly, you must adjust two of three parameters.
1. Effective length.
2. Inner null.
3. Outer null.
If you insist to align just one null, inner null, or outer null, you must adjust effective length first. But effective length varies from arm to arm. This is why I highly praise Mr. Hoffman's app. Every alignment template made with the app is custom-made for your arm only. You also have the option to choose Lofgren A or B, or Steveson. I would be very happy to see he can add Uni-D if possible. Besides that, IT IS FREE. If you are willing to pay for a piece of plastic, do you get this many options? Is the plastic highly customizable as the app? No.
If you want to align your cartridge correctly, you must adjust two of three parameters.
1. Effective length.
2. Inner null.
3. Outer null.
If you insist to align just one null, inner null, or outer null, you must adjust effective length first. But effective length varies from arm to arm. This is why I highly praise Mr. Hoffman's app. Every alignment template made with the app is custom-made for your arm only. You also have the option to choose Lofgren A or B, or Steveson. I would be very happy to see he can add Uni-D if possible. Besides that, IT IS FREE. If you are willing to pay for a piece of plastic, do you get this many options? Is the plastic highly customizable as the app? No.
I have not seen you protractor, but have you thought of putting another layer in the middle to help with parallax? Like a red layer in the middle…
Just an idea I’ve e had…
Thanks
Hello Johnny seen you asked I managed to dig it out , I didn't realize it but I think its Japanese -Osawa .
Not only has it parallel lines but at the two indicator poinbts its cross-hatched for accuracy done pretty finely.
You line it up to point "A" first and then point "B".
Here is some photos & info of the Ortofon version -
Cartridge alignment tool- Vinyl Engine
Bl--dy ,ell ! a later version is selling at £90 .
The world has gone crazy the original which I have is gone on eBay.
Not only has it parallel lines but at the two indicator poinbts its cross-hatched for accuracy done pretty finely.
You line it up to point "A" first and then point "B".
Here is some photos & info of the Ortofon version -
Cartridge alignment tool- Vinyl Engine
Bl--dy ,ell ! a later version is selling at £90 .
The world has gone crazy the original which I have is gone on eBay.