Graham Phantom Anti-Skate. Is it effective at all?


I've had my Phantom Supreme over a year now, and for the most part it's been a pleasure. Beautiful build & sound; awesome VTA and azimuth adjustments. My main hangup had been the headshell; getting a Koetsu to sit flat on the 10" wand seemed impossible because the correct overhang pushed it all the way to the back, behind the main headshell points of contact. Finally I just used 2 plastic washers as shims to get a nice flat mount.

Now my main concern is the anti-skate. I'm not sure if all Phantoms are this way or if it's an issue with my unit. I can't seem to get an effective amount of anti-skate. My preferred method for adjusting anti-skate is to drop the needle in some dead-wax before the label (NOT into a lead-out groove) and adjust so that the stylus creeps *slowly* inwards. With my Graham, I cannot achieve that...it always moves quickly inwards no matter how far out I set the weight. Even physically pushing down on the weight doesn't seem to have much effect in swinging the arm. To me, this seems like the mechanism is not effective, as if I'm running without any compensation. This is very unlike my experiences with a Fidelity Research FR64fx (weight and fishing line) and Clearaudio Magnify (magnetic) -- both have a very noticeably effective anti-skate mechanism, which I can easily dial-in as described above. In fact I just setup a Magnify...it was great!

On my Graham, the pulley & rope system seems to be correctly in place. But without a 2nd until to examine, I can't determine whether this is normal. Could other owners/users of Graham please comment on their experiences with its anti-skate? The situation is OK for now -- I burn hours on my good cartridges very slowly and sparingly -- but I'd rather not have my nice cartridge seeing asymmetric wear over the long-run.

-- Mike
Ed430d47 c595 4a82 8f69 3edcb7ac3455mulveling
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.
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

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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.

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.