So can you explain why AS is not necessary with an air bearing linear tracker? The mechanical ones will render the explanation for the air bearing arm moot so we can dispense with that. I'm putting a bit of a challenge but all in good fun. 🙂
So here is a good discussion:
So here is a good discussion:
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Oops. Here: Origin of the skating force finally understood by me- Vinyl Engine
Although it should be mentioned the type/shape of the stylus changes it affirming that it is only the offset friction in play, the inertia caused by the pendulum is swamped by this. That's why a grooveless surface is useless in this regard.
Although it should be mentioned the type/shape of the stylus changes it affirming that it is only the offset friction in play, the inertia caused by the pendulum is swamped by this. That's why a grooveless surface is useless in this regard.
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I am simply doing public service for those who want to accurately adjust anti-skating and who want to know where the skating force comes from. Please read Mr. Kogen's classic analysis of the skating force first.
That's a great analysis. However it does reaffirm my position it needs to be done on the fly to obtain the precision this paper establishes. The variables are too many to rely on calibration marks for accuracy, the critical accuracy implied by this very well written essay itself.
Thank you super10018 and lcsaszar for bringing some light (basic knowledge of geometry and forces) to those who navigate in the dark.....!
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Skating force depends on the drag on the stylus (in a pivoted arm) caused by the record it is tracking. The amount of this drag depends on the amount of modulation & frequency content in the tracked grooves. So it varies continuously during play and all you can do is set off an average value of anti-skate force and let it go at that. Loud records need more, and quieter ones need less.
Thanks also to you.
The Vinyl Engine link you quoted, did you read it completely?
The friction of the prong against the inner wall of the groove is the result, not the cause, of the centripetal force that is caused by the tangential error of the arm. As I have already told you before, the answer is something so obvious to everyone, that it did not deserve an answer from me, but, as I see that you insist, I will clarify it.
Goodbye, have a good trip accompanying your worm through the depths of ignorance.
Final point 😛!
According to the research paper by Shure that was linked to earlier in this thread, the amount of additional skating force as modulation level rises is not excessive and is a small percentage of the baseline amount of skating force in an unmodulated groove.
Moreover, the additional skating force generated from modulation is much reduced with elliptical styli compared to spherical tip styli. I suggest that the primary cause of the rise in skating force with rising modulation level in the case of spherical tip styli is the 'pinch effect'.
The dynamic skating force generated by spherical styli in a modulated groove is very close to the dynamic skating force generated by elliptical styli in the same groove, which might explain why turntables typically do not have seperate scales for different shaped styli these days.
Hello johnmath :
I have cleaned the rubber of the platform that raises the arm, as you have advised me and I have carried out some tests according to the attachment and the paragraph that I highlight:
" Almost always, most tables are set so they have too much Antiskating, or an adjustment that cannot be turned down enough, OR the range and fine control is terrible, or you have none.
Usually, most folks use far too much antiskating, as evidenced by the thousands of cartridges I have rebuilt over the last 40+ years – as evidenced by observation of the outer edge (right channel) of the diamond to be worn far more than the inner, or left channel.
A properly designed anti-skating is non-linear, as it should of course increase A-S automatically as the cartridge approaches the inner grooves.
Frank Schroder and I are of the same opinion about antiskating – and that renders MOST records that provide an anti-skating track totally in error – they are recorded at about 80-90% modulation – or HIGHER - and expect you to set the A-S force so that there is no distortion (or equal amounts on both channels if the cartridge tracks poorly).
The problem with these tracks is that since the required level of A-S force is a dependent of the amount of modulation, it has you adjust antiskating at far too high a level. This would be OK, if you are listening to music that is (by nature of the music) at constant maximum crescendo, without normal musical dynamics - going from loud to soft. Very few pieces of music are like this. When you adjust for this level on a “test record”, that means that you are very much overcompensated with far too much antiskating as you have adjusted it for where music does NOT spend most of its time. It spends it at about 30-40% modulation levels, and adjusting the A-S with these “test” records results in far too much A-S force; too much stylus force on the right channel, and far too little on the left.
Since there is no properly recorded track that allows proper setting of A-S (there will be such on our new Soundsmith adjustment record), the method that Frank Schroder discovered through careful reverse engineering works without tools, and without a special record.
If one sets the stylus on a smooth surface of a record (at the end, in-between the run out grooves) – the tip of the stylus has a drag on the surface that somewhat similar to what it would have if it were in a groove. This is due to a calculation of “force per unit area” with consideration of the rheology of the material – vinyl.
Suffice it to say that it is “similar” enough for this method to work well, especially since the method was reverse engineered/calibrated properly by Frank Schroder to be correct for 30-40% record modulation. It then becomes an easy matter to set the A-S and observe the movement of the arm. For a given VTF (any amount of VTF) – set the A-S so that the arm VERY SLOWLY drifts inwards when placed on the SURFACE (NOT IN A GROOVE) at the end of a record. You will have a moment to do this until the stylus “pops” into the run-out groove.
This works for ANY amount of VTF required, for ANY cartridge. It will set the A-S for EQUAL force per groove wall for 30-40% groove modulation levels, at ANY VTF, for ANY cartridge. "
https://www.sound-smith.com/faq/how-do-i-adjust-anti-skating-my-cartridge
My settings
Tracking force is 1.8 grams.
1 - I adjust the AS according to the manufacturer's marks (the indicator adds about 0.2 / 0.3 grams + for the elliptical needle, such as the Ortofón 2MRed.
2- The VTF is set at the one recommended by Ortofón, 1.8 grams.
3- the arm slides out of the start of the LP quite steeply! That is wrong.
4- I place a flat surface, the RX is much longer than the test disc, it is cut exactly to the size of the vinyl.
5- I reduce the force of the AS until the arm is
move slowly in the final sector of the vinyl (absent) 6- I observe the resulting position of the indicator: 0.5 grams.
A difference of 2.3 grams !!! 😱
So tomorrow I will take the 60X magnification and examine the needle from the old cartridge, Stanton 881S that I stopped using when I noticed uneven wear on it.
If the wear is on the side corresponding to the right channel (the outside of the groove) it will be proof that the factory AS is excessive......😱😀
I have cleaned the rubber of the platform that raises the arm, as you have advised me and I have carried out some tests according to the attachment and the paragraph that I highlight:
" Almost always, most tables are set so they have too much Antiskating, or an adjustment that cannot be turned down enough, OR the range and fine control is terrible, or you have none.
Usually, most folks use far too much antiskating, as evidenced by the thousands of cartridges I have rebuilt over the last 40+ years – as evidenced by observation of the outer edge (right channel) of the diamond to be worn far more than the inner, or left channel.
A properly designed anti-skating is non-linear, as it should of course increase A-S automatically as the cartridge approaches the inner grooves.
Frank Schroder and I are of the same opinion about antiskating – and that renders MOST records that provide an anti-skating track totally in error – they are recorded at about 80-90% modulation – or HIGHER - and expect you to set the A-S force so that there is no distortion (or equal amounts on both channels if the cartridge tracks poorly).
The problem with these tracks is that since the required level of A-S force is a dependent of the amount of modulation, it has you adjust antiskating at far too high a level. This would be OK, if you are listening to music that is (by nature of the music) at constant maximum crescendo, without normal musical dynamics - going from loud to soft. Very few pieces of music are like this. When you adjust for this level on a “test record”, that means that you are very much overcompensated with far too much antiskating as you have adjusted it for where music does NOT spend most of its time. It spends it at about 30-40% modulation levels, and adjusting the A-S with these “test” records results in far too much A-S force; too much stylus force on the right channel, and far too little on the left.
Since there is no properly recorded track that allows proper setting of A-S (there will be such on our new Soundsmith adjustment record), the method that Frank Schroder discovered through careful reverse engineering works without tools, and without a special record.
If one sets the stylus on a smooth surface of a record (at the end, in-between the run out grooves) – the tip of the stylus has a drag on the surface that somewhat similar to what it would have if it were in a groove. This is due to a calculation of “force per unit area” with consideration of the rheology of the material – vinyl.
Suffice it to say that it is “similar” enough for this method to work well, especially since the method was reverse engineered/calibrated properly by Frank Schroder to be correct for 30-40% record modulation. It then becomes an easy matter to set the A-S and observe the movement of the arm. For a given VTF (any amount of VTF) – set the A-S so that the arm VERY SLOWLY drifts inwards when placed on the SURFACE (NOT IN A GROOVE) at the end of a record. You will have a moment to do this until the stylus “pops” into the run-out groove.
This works for ANY amount of VTF required, for ANY cartridge. It will set the A-S for EQUAL force per groove wall for 30-40% groove modulation levels, at ANY VTF, for ANY cartridge. "
https://www.sound-smith.com/faq/how-do-i-adjust-anti-skating-my-cartridge
My settings
Tracking force is 1.8 grams.
1 - I adjust the AS according to the manufacturer's marks (the indicator adds about 0.2 / 0.3 grams + for the elliptical needle, such as the Ortofón 2MRed.
2- The VTF is set at the one recommended by Ortofón, 1.8 grams.
3- the arm slides out of the start of the LP quite steeply! That is wrong.
4- I place a flat surface, the RX is much longer than the test disc, it is cut exactly to the size of the vinyl.
5- I reduce the force of the AS until the arm is
move slowly in the final sector of the vinyl (absent) 6- I observe the resulting position of the indicator: 0.5 grams.
A difference of 2.3 grams !!! 😱
So tomorrow I will take the 60X magnification and examine the needle from the old cartridge, Stanton 881S that I stopped using when I noticed uneven wear on it.
If the wear is on the side corresponding to the right channel (the outside of the groove) it will be proof that the factory AS is excessive......😱😀
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The factory setting for antiskating will certainly not be correct unless all of the following conditions are met:
Built in VTF gauges on turntables are just as likely to be incorrect as built in antiskating gauges and you can't assume the tracking weight is correct without a proper balance scale.
Antiskating is the last setting once all of the others above are verified as correct. My experience using test records of varying modulation level that the modulation level effect is small except for spherical styli, nor is there a difference between dynamic settings using the test tracks and the runout space skating test described in the Sound-Smith article.
Obviously if any of the 6 setups listed above is not correct then all discussion about setting antiskating force is moot. I suspect the fact that some of these conditions are not easily possible to verify, and that setting overhand and offset is actually quite difficult for the inexperienced is why there is so much disagreement on forums like this.
I often have to compensate for incorrectly mounted stylus tips, and sometimes they are so bad I just cannot get a turntable set up properly at all. Price is no indicator either: a few of the cartridges that I have sent back to the supplier were several thousand dollars, including a top Van den Hul, Dynavector and several Linn Arkiv cartridges.
I have also had to compensate for twisted tonearms that don't have azimuth adjustment by either shimming the base of the tonearm or putting a shim above one side of the cartridge body, depending on how the error manifests. A shim of 0.05mm under one side of a cartridge rotates the cantilever relative to the record by ~3º a quite significant amount for a line contact stylus.
- the VTA is correct,
- the azimuth at the stylus tip is correct,
- the perpendicularity of the stylus tip to cantilever / centerline of cartridge body is correct,
- the overhang is correct,
- the offset angle of the cartridge is correctly set with a two point protractor, and
- the tracking weight is correct.
Built in VTF gauges on turntables are just as likely to be incorrect as built in antiskating gauges and you can't assume the tracking weight is correct without a proper balance scale.
Antiskating is the last setting once all of the others above are verified as correct. My experience using test records of varying modulation level that the modulation level effect is small except for spherical styli, nor is there a difference between dynamic settings using the test tracks and the runout space skating test described in the Sound-Smith article.
Obviously if any of the 6 setups listed above is not correct then all discussion about setting antiskating force is moot. I suspect the fact that some of these conditions are not easily possible to verify, and that setting overhand and offset is actually quite difficult for the inexperienced is why there is so much disagreement on forums like this.
I often have to compensate for incorrectly mounted stylus tips, and sometimes they are so bad I just cannot get a turntable set up properly at all. Price is no indicator either: a few of the cartridges that I have sent back to the supplier were several thousand dollars, including a top Van den Hul, Dynavector and several Linn Arkiv cartridges.
I have also had to compensate for twisted tonearms that don't have azimuth adjustment by either shimming the base of the tonearm or putting a shim above one side of the cartridge body, depending on how the error manifests. A shim of 0.05mm under one side of a cartridge rotates the cantilever relative to the record by ~3º a quite significant amount for a line contact stylus.
The thing is though, that considering none of the parameters can be perfectly satisfied, setting VTA and AS on the fly compensates for the accumulated errors. So in this case, all other parameters become moot; as long as they are in the ball park. Remember, VTA changes with every record.
To get three degrees, that shim would have to be 1mm thick, not 0.05mm.
A shim of 0.05mm thickness would only give 0.15 degrees, which is twenty times less.
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Oops, thank you for picking up my senior's moment! According to the online calculator linked below a 0.05mm shim on one side of a 12.7mm (½") mount would give 0.23º error.
Trigonometry Calculator
Looking back at my notes on a particular setup of an Audio Technica AT33PTG/II on a Rega RB2000, a shim of 0.1mm was required with shims ±0.03 (0.13 & 0.07) giving equal and opposite channel balance errors. The 0.1mm shim equates to an error of 0.45º. The AT33PTG/II has a highly refined line contact stylus particularly sensitive to misalignment.
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I only ever deliver turntables with the cartridge body/headshell parallel to the playing surface on a 120g record. What people do in the privacy of their own homes is their business, however no one has ever come back to me and complained or even commented that the VTA was suboptimal.
The effect of record thickness on VTA is much smaller than the effect of the tracking weight being slightly out of specification. In fact if the cartridge manufacturer gives a range for tracking weight, say 1.8 to 2.2g, there will be several degrees of VTA variation over this range, far more than can be compensated for by varying the tonearm height in most cases.
A record that is not flat can also have ±several degrees of tracking angle error per revolution. Also modulation level affects the effective cutter head VTA because of physical lacquer distortion during the cutting action. For perspective altering the tone arm pivot height of a 220mm long tonearm by 2mm will alter the VTA by just 0.5º.
I don't doubt that some people find the VTA a very sensitive adjustment, but like antiskating force, I can only assume that VTA sensitivity is a result of the other critical cartridge setup points being all over the place, possibly to lack of precession by the manufacturer in the placement of the stylus tip on the cantilever (not at all uncommon) and/or error in the basic alignment of the cartridge.
The only way to verify is by ear. VTA and AS are at best average values. The source which is the record, skews the math to the point where it becomes meaningless. Precision is an elusive ideal and although for all intents and purposes it must remain the goal, on the fly adjustment is the best compromise. As I've mentioned, unless you've experienced this you cannot appreciated the magnitude of it's effect and reality. When I'm framing a house, unless I'm as precise as possible during the course of the build, the accumulated errors will compound and result in an overall hugely out of alignment structure. As it is, the final error is only as large as the first tiny one thanks to my trusty laser. With the tt the laser is your ears that let you discover the error.
I absolutely agree that VTA and AS are at best average values.
A absolutely disagree that the maths is skewed. The only reason turntables have evolved to such a high standard of fidelity is the rigorous and astute application of mathematics to the design of all aspects of creating and replaying vinyl records.
What I mean is the math ends up skewed due to the impossibility to apply it precisely on the tonearm. No good intention goes unpunished so to speak. 🙂
By observing the Stanton 881S capsule, with the gadget that you see in the attachment, I confirm that indeed the needle is much more worn on the external side, as I had already imagined.
It was impossible for me to take a picture with the smart phone, sorry.
So, and responding to my own concern since I am the OP, I come to the conclusion that the "factory" AS settings tend to be excessive.
But, likewise, a difference of 1.3 grams (there was an error there, I added instead of subtracted) also seems excessive to me, especially in a brand that enjoyed great prestige and manufactured excellent arms and TT at the time.
So to regulate the AS according to post 30, it seems to me that it will be too little, I just use my intuition here, some phrases seem too pretentious to me, like the one that states that "this setting works with any VTF and with any cartridge" ..
So I adjusted AS in the middle, that is, when the arm / needle remains static on the RX plate in the middle, placing the plate on a vinyl of normal thickness.
Now to enjoy music, which is finally the leitmotiv that concerns us.🙂
Attachments
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The usual cheap spring loaded antiskating found in most turntables is very adaptable to all situations (including that it has automatic callibration with respect to tonearm's position on the record) except the frequency content but even if it would be completely automatic , no mechanical automation would be able to respond in a timely manner to frequency content change on the record so we just have to rely on average settings and accept stylus wear on the external side of the antiskating as our ear is usually used to make the final setting and human hearing is mostly sensitive to mid highs frequencies which makes us set the antikating always too much outwards .
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