I am not anal about it. I try to use the minimum possible. I also observe the cantilever when it drops on the record to see if it deflects on impact when it starts it's groove travels. Not a perfect method by any means but works for me with the arms I use....close enough, imo. I also pay close attention to the inner groove right channel and listen for distortion...and apply more skate if needed. |
I also observe the cantilever when it drops on the record to see if it deflects on impact when it starts it's groove travels. Not a perfect method by any means but works for me with the arms I use On impact the stylus suspension will be stretched and the elasticity of the joint will be at its maximum. Therefore this is the worst time to measure anti skate using cantilever flex as a measure. It would appear far more logical to me to check that the cantilever is centred whilst playing. The caveat here is that many folk adjust anti skate without checking that the horizontal bearings in the tonearm are level - a few microns out can affect antiskate requirement significantly. The other trap using listening or channel balance is the possibility that one might use anti skate to compensate for other system issues. Personally for anti-skate I am looking for accurate set up of turntable and arm first - ensure that both platter is perfectly level, check that the horizontal arm bearings are perfectly level by balancing the arm to zero and check that there is no float in or out, I check that a small tap creates the same travel distance in both directions ( with the arm balanced to zero ). As a high end dealer many years ago my experience is that many arm boards are not level when the platter is level. Furthermore in many gimbal type arms I have found that when the arm base is level, the horizontal arm bearings are not. This is why the float test is very important and will help to minimise anti skate. Then after careful set up of the cartridge including alignment, VTA, tracking weight ( its an iterative process ) for anti-skate I check that the cantilever is centred whilst playing in the middle of a record. Using your ears before and after each adjustment is helpful. I would expect that a unipivot arm ( like the VPI ) will have less issues with anti skate than a gimbal arm because the issue of ensuring the horizontal bearings are perfectly level does not arise, and the bearing friction should be considerably lower if the unipivot has been designed correctly. |
As a high end dealer many years ago my experience is that many arm boards are not level when the platter is level. Furthermore in many gimbal type arms I have found that when the arm base is level, the horizontal arm bearings are not. This is why the float test is very important and will help to minimise anti skate. the best posting I read in the last 3 years here about AS. I agree and I am amazed, that only Dover detect that a lot of Arm boards are not correct in combination with a level platter. Famous example of our modern time are the ones for Germany, mainly black, surrounded by a few motors and bought from customers who prefer to read hypes rather than to think about what they buy. But there are more out there. I also agree with the Arms, we have Fans who prefer wood tubes for several thousand $$, or plastic, or simply wrong executed tubes...and there is only one out there who used his brain to develop something useful, The Axiom Arm from Acoustical Systems. It has an independent leveling. A nice detail which will never get the respect it deserves :-) The AS depends also on Arm Geometry (---> Arch Angle for example), when that is weak you can adjust whatever you want...day in ...day out....or those low VTF designs, which ruin the cantilever on their own while playing...some manufacturers offer a re-align service after buy...I miss the time of the good, old 2,5gr VTF units...they were buried because they run too long :-) |
The constant outward deflection of the arm... exerts a force that inhibits the stylus and produces a side damping. One wants the stylus to be absolutely free to negotiate its travels. Bingo! That's what I hear. It sounds exactly like using too much VTF. How much is "excessive"? With my best cartridge, *any* amount of A/S audibly compresses dynamics and raises the sound floor. Totally agree with Dover's methodology, very astute and technically correct IMO. However, I prefer the improved sonics from zero lateral damping and from reducing the doohickeys hanging off my tonearm. I buy gear and LPs to listen to music. If optimizing sonics has some slight impact on the life of my gear or LPs I won't live long enough to hear it, but I'd notice impaired sonics in a heartbeat. |
. Stringreen, and Doug A/S is included with tonearms as a selling point....when skating became the new adjustment of perfection, it was hard to sell an arm without it. In truth, A/S is very illusive...there are so many factors that contribute to it that there is just no way to adjust so that it does what intended. Most arms, when set according to directions apply WAY too much a/s . The constant outward deflection of the arm...when not needed...especially with too high a setting, exerts a force that inhibits the stylus and produces a side damping. One wants the stylus to be absolutely free to negotiate its travels. It is not the case that antiskate is some sort of sales thing . As mentioned above there is good reason that for half a century or more probably more than 99.9% of arms had and still have it. Antiskate is provided to compensate for skating forces. You adjust it to equalise distortion on each channel. If you run an arm without it then by definition one channel must have more tracking force than the other. End of story. Unless, of course, your arm is providing a force by some other means, eg inadvertently through using heavy wire through the bearing, such as Cardas, or twisting the wire deliberately, such as VPI or AR, or being off level, or having stiff bearings. And, of course, it is cheaper to make an arm without the facility. With no antiskate there are force acting to pull the arm inwards. If you complain about the effects of the outward force applied using antiskate, but to where does the inward force magically disappear when not using it? None of the anti skate advocates have addressed this, nor why the unequal forces mysteriously don't cause distortion. There must be compensation with extra downforce (all things being equal), to increase the VTF on the right channel. All this is not to say that all antiskate methods are perfect. Their physical presence may well affect the sound. And of course the arms on which they are used may suffer from the above mentioned wiring and other issues, so rendering the mechanism redundant. John . But If it all sounds ok because fair enough. |
John ...even your last sentence is wrong. I suspect that there is such a thing as skating force....but it is a very slight, illusive and constant changing force. It is impossible to correct for it and most times it is overcompensated. Why do you say that there is distortion on one channel without A/S ?? If the vtf is adjusted properly, the stylus stays in the groove with no mistracking. The bottom line is that MY arm/cartridge sounds better with no A/S, therefore that is the better way. I tried it (a few times) with A/S, but the sound is always better without it. |
As far as impact, I'm looking for deflection after the record groove is being
traced. You need to look at it before, during and after to see if it's consistent
with how it looked before dropping on the LP. It takes concentration. Even
so, I'm not too concerned about it...little is better than too much. |
...and there is only one out there who used his brain to develop something useful, The Axiom Arm from Acoustical Systems. It has an independent leveling. A nice detail which will never get the respect it deserves :-)
Actually the Schroder LT had that feature before the Axiom came out. It is a very good idea. |
John, You quoted Stringreen's contention about why tonearms include A/S but also addressed your rebuttal to me, as though I had seconded that statement. I didn't and I don't. Please don't ask me to defend statements I haven't made. I'm unaware that any tonearm designer (except Harry Weisfeld) has publically stated why their tonearms offer A/S. Like you, I'm prepared to believe they do so in an attempt to counter these proven (if largely unquantifiable) forces. *** If you complain about the effects of the outward force applied using antiskate, but to where does the inward force magically disappear when not using it? None of the anti skate advocates have addressed this, nor why the unequal forces mysteriously don't cause distortion. The inward force doesn't magically disappear, obviously. However, it does not necessarily result in distortion. Here's why: Skating forces put an inward bias on the stylus. The stylus wants to skate inward but is constrained by the inner groovewall. Of course the stylus may lose contact with the outer groovewall. THAT will cause R channel distortion. However, so long as steady contact is maintained with both groovewalls, no distortion will occur. If the stylus traces the grooves accurately, it will reproduce accurately (for its part). The question becomes, how best to maintain constant stylus-groovewall contact. As I've repeatedly said, with MY cartridge on MY tonearm, this is best achieved by zero lateral force and very careful tuning of VTF (I routinely tweak by much less than .01g). As I've also repeatedly said, other rigs may and often do respond differently. *** I'm open minded. I'd be happy to use an A/S device that operated correctly. Unfortunately, the mechanics of a correctly operating A/S device, while theoretically possible to describe, are virtually impossible to achieve in practice. Skating forces act on the stylus (NOT the tonearm). Therefore, the ideal A/S device would counteract those forces AT THE STYLUS. The notional perfect device would be a self-adjusting, elastic thread attached to the STYLUS and pulling outward. Aside from being practically impossible to build and operate, even this otherwise perfect solution would still be challenged by not knowing exactly how much outward pull is needed to counteract the varying amount of skating force encountered from one musical passage to the next. Still, if such a device existed or could exist, I'd give it a try. *** Unfortunately, every real A/S device acts on the TONEARM. This is the only practical way to build it but this incorrect implemention causes the distortions Stringreen and I dislike, because it applies the counteracting lateral force at the wrong place. The LP is pulling inward on the stylus while the A/S device is pulling outward on the tonearm. Where are these counteracting forces mediated? In the only place that there's elasticity to prevent something breaking: the elastic suspension between the cantilever and the cartridge body. As Stringreeen correctly stated, this external pressure causes artificial damping of the cantilever. This would not occur in our notional perfect A/S device, but as we've seen, that does not and probably cannot exist. With A/S applied at the tonearm, in MY system, the sonic degradation is instantly audible. Your system or ears may well respond differently, of course. |
The LP is pulling inward on the stylus while the A/S device is pulling outward on the tonearm. Where are these counteracting forces mediated? In the only place that there's elasticity to prevent something breaking: the elastic suspension between the cantilever and the cartridge body. Doug, you may very well be right about this assertion. It has a common-sense ring of truth. And I don't doubt that your rig sounds better (to you and others) without A/S; this vector-force narrative would seem to explain it in a scientific way. But I have to wonder about the actual physics of it. Now, I'm not a physicist (my PhD is in English, not Physics) but it seems logical to me that, with a rigid tonearm, the lateral force of the A/S device is transferred to the stylus, and the "mediation" of this force through the elasticity of the cartridge suspension would occur only if the A/S force is being met with a countervailing force at the stylus tip, in other words, the outside groove wall. Under these circumstances, of course, too much A/S force is being applied. Otherwise, the transmitted force merely relieves pressure on the elasticity of the cartridge suspension, pressure caused by too little A/S. I'd love to have someone qualified in the physics of tonearm geometry and vector forces weigh in on this fascinating subject. |
For precision, I should have said: "...and the *deleterious* 'mediation' of this force through the elasticity of the cartridge suspension would occur only if the A/S force is being met with a countervailing force at the stylus tip...." |
Dougs point about the anti skate been applied to one end of the cantilever and the skating force being applied to the other is quite correct. However IF one has checked that the cantilever is straight, and not being pulled in one direction or the other whilst playing ( assuming one can find a record that is not eccentric ) then this argument has less weight. In terms of the physics then the effective mass and cartridge compliance come into the calculation. The issue here is that not many cartridge manufacturers specify the lateral compliance, and in my experience some low compliance cartridges are quite compliant in the horizontal plane and vice versa.
Furthermore if a cantilever is leaning one way or the other, then clearly the magnets or coils could be sitting in a position where there is more non linearity within the electrical/magnetic fields.
Many arms have inbuilt anti skate anyway. In the case of the VPI's the twisted loop of tonearm wire is far too stiff in my view and exerts both an anti skate and a rotating force affecting azimuth. In other arms the tonearm wire is often impeding free movement in the bearings as John pointed out.
Antiskate systems themselves can be problematical - spring, hanging weight, elastomer thread, weighted lever - they all have their pros and cons. It is a horses for courses scenario where you end up, but the process for determining the optimum ( or "none" ) anti skate should be consistent.
As an aside, whilst having a hiatus from audio, I used a Shure V15Vxmr ( with stabiliser brush removed ) for about 10 years on an ET2 linear tracker ( high horizontal mass, no skating forces ). I had added a little magnetic damping to the bearing tube motion using the eddy fields generated from the motion of the tube across the magnets. After 10 years the original cantilever was still dead straight and the cartage was sold for more than I originally paid. |
Because unipivot arms are balanced on the point of a pin, if the arm is set up properly it will compensate for any nonlinearity elsewhere. |
My vinyl experience over the years has not included LOMC's or other cartridges having relatively low compliance, such as I presume most of those participating in this discussion are using. FWIW, though, using MM's and MI's having relatively high compliance (primarily Grace F9-E variants, including non-Ruby, Ruby, and Soundsmith re-tipped Ruby versions), primarily on a Magnepan Unitrac unipivot arm, with VTF generally set in the upper part of the recommended range for the particular cartridge, I have over the years consistently found that:
1)Left or right deflection of the cantilever, as viewed from the front of the cartridge when playing a record, will closely match the corresponding angle (nominally straight ahead) that is assumed by the cantilever when the stylus is raised above the record if anti-skating is set to approximately 50 to 65% of the amount recommended for the particular tonearm at the particular VTF.
2)A setting can be found in that range which will result in imperceptible left or right cantilever deflection at ALL points on the record.
3)Modest deviations from that amount of anti-skating force (either higher or lower) will ALWAYS (IME, as described) produce clearly perceivable sideways deflection of the cantilever while playing a record, which will NOT vary perceptibly as a function of what part of the record is being played.
4)I have never tried an anti-skating setting approaching zero, because given the foregoing it would seem absurd to do so in these particular circumstances.
Hopefully that datapoint will be of some usefulness in the discussion. Best regards,
-- Al
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Doug: I don't expect you to defend Stringreen. I addressed you and him as you were both in the no- antiskate camp, and you had agreed with his point. You said Skating forces put an inward bias on the stylus. The stylus wants to skate inward but is constrained by the inner groovewall. This is incorrect. It is the arm that pivots inwards because of the resultant force produced by stylus friction in the direction tangent to the groove and the restraining force in the direction of the arm pivot. The stylus, on the other hand, is actually being pushed upwards and outwards against the compliance of the suspension as the cantilever pivot moves inwards. However, so long as steady contact is maintained with both groovewalls, no distortion will occur. If the stylus traces the grooves accurately, it will reproduce accurately (for its part). As the stylus is pushed up the 45 degree slope of the groove, the VTF on the opposite face decreases. Applying antiskate pulls the arm (and therefore the cantilever pivot) outwards thus equalising the VTF on both channels. The inward and outward forces are then equal at both the stylus and the cantilever pivot, as they are joined by the cantilever, and the plane of movement of the cantilever is therefore vertical. If there is no antiskate (intentional, or otherwise via wiring) then the forces must be unequal, and with enough VTF, while the stylus may track correctly without the distortion due to low VTF on the right channel, that channel will have appreciably more tracking force than the left. And any alteration of VTF will still vary downforce disproportionately. Arms are designed to have a mechanism to allow some form of compensation for skating force, as the force cannot be wished away. It is what designers do. It is good basic arm design, like having variable VTF. It is for designers who don't wish to include it to try to explain their decision. Whether is is well implemented, or compromised by wiring torque, or the user wishes to use it, is another matter. Stringreen: In my previous post the last sentence was wrong - it was a typo. To the OP, Mulveling: If all set up parameters are correct, and an arm cannot supply sufficient antiskate to eliminate right channel distortion, then there may be stiffness in the bearing (not usually the case with unipivots) or drag in the internal wiring. John . |
Regardless of whether you choose Baerwald, Lofgren, or Stevenson, the alignment is based on 3 parameters or measurements: PivotToSpindle, PivotToStylus, and OffsetAngle. Fix any two, and proper alignment will require you adjust the third.
If you have an arm with a fixed mounting position on the table then the first is set as well as the OffsetAngle. This leaves only the abiity to change PivotToStylus unless you don't mind varying the OffsetAngle in the headshell.
Let's say you have an arm mount which allows you to vary the PivotToSpindle. In such a case you should be able to pick a good position for your cartridge in the headshell slot, with the cartridge straight (not rotated), thus fixing two of the three parameters. Then you could achieve proper alignment by sliding the arm mounting position.
Sometimes, the specified PivotToSpindle distance is not optimum. My old Fidelity FR64 allowed for easy rotation of the cartridge in the headshell. This was useful since when mounted using the template, fixing the PivotToSpindle, and installing the cartridge, fixing the PivotToStylus, only the offsetAngle could be adjusted. The old Fidelity arm mounting posiiton was not specified with Baerwald in mind. But, if you can move the arm mount, you could set the cartridge square in the shell and then move the arm base as needed.
Thankfully, the current VPI JMW PivotToSpindle spec seems to be correct for easy alignment using any of the 3 Alignments (Baerwald etc.)
It seems to me that the choice of which optimization to use (Baerwald etc) can be informed by the predominant type of record played. I prefer the Baerwald's more gentle degradation of the tracking angle error at the record center since I listen to much classical music which often runs to the limits of the inner radius and will often have crescendos at the end of a side.
As far as anti-skating being unimportant: It seems to me that is nonsense since a lack of anti-skating force is easily heard in highly modulated groove passages as gross distortion/breakup.
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Well this thread was resurrected lol. I’ve moved on from my Graham to a Fidelity Research FR64S arm for my Koetsu cartridges, and FR64fx for my back arm (the Graham sounded good but the 64S is notably better). On both of these FR arms, the anti-skating mechanism is obvious and effective - push down (carefully) on the weight, and the arm skates inwards, in a VERY sensitive fashion. On the Graham Phantom II Supreme, when you push down on its anti-skate weight (even with the weight adjusted for maximum leverage) you get virtually NOTHING - literally, almost no movement at all. Kind of like the pulley thread’s attachment point to the main bearing housing is in the wrong place (and not just by a mm or two - more like, way a lot off). I guess they could say the anti-skate mechanism only works dynamically when in-use because of the MagnaGlide system (yada yada), but quite honestly I don’t see how that makes a significant difference at all. Anyways, it’s quite easy to vastly over-adjust on the FR arms so that the stylus starts skating OUTWARDS on blanks, and with the Graham even at max setting it was not clear to have ANY effect at all towards slowing the inwards skate. It seems a lot more likely that the anti-skate system was attached wrong. Perhaps it’s just my unit, or perhaps it’s that model. BTW the main bearing is perfectly smooth and friction-free, and the magnaglide is correctly aligned and does a wonderful job stabilizing the unipivot; that’s not the problem. I think it’s become pretty clear the problem is isolated to the anti-skate mechanism.
Also I didn't intend for this to become a holy war on anti-skate philosophies, lol. Mine is that some is better than none, but it's better to use too little of it than too much. It just bugged me that my Graham arm seemingly couldn't apply any effective anti-skate force at all. |
