Anti skate and tonearm damping query

Stan, the tonearm manufacturers are indeed now catching up with the essential differences between MC and MM cartrige requirements. Or to be more specific, the difference in the tonearm settings required by cartridges with line contact styli and previous types of styli. One example of this response by manufacturers is the SME IV.V which is made specifically with MC-with-line-contact-styli in mind. It's like an SME V, but comes without silicon damping (unnecessary for MC cartridges' stiff suspensions) and without hairspring VTF adjustment (also unnecessary for cartridges tracking in the 2 gram range.) Further, no current manufacturer of quality tonearms is silly enough to assert that the user just blindly set the antiskating force scale indicator to match the VFT setting. They all know better by now ;-)

As I indicated previously, the reason MC cartridges, or more accurately, cartridges with line contact styli, require so little antiskate compensation, is because they create so little skating force to begin with. Simply put, for each gram of VTF, a line contact stylus "drags" in the groove just a fraction of the amount that a conical or elliptical stylus would. And since 'skating force' is a product (read: multiplication result) of stylus friction drag TIMES the length of a (virtual) lever arm which is created by headshell offset angle. Therefore, lower stylus drag produces less skating force with a given tonearm.

If a tonearm has no headshell offset angle (like some of the old 12 -16 inch transcription tonearms) then no skating force is produced because there is no (virtual) lever arm for the stylus "drag" to act upon. However, with long tonearms, you still pay a small price in increased tracking error and a big price in tonearm resonance and inertial momentum (the tonearm wants to keep going UP after a record warp ;-)

If you want to have your cake and eat it too, get a linear tracking tonearm - no skating force, no tracking error, stylus rake angle (SRA) adjustable while the record is playing - and they do sound fabulous, I've had one. BUT, they ARE a hassle, needing (usually) an air pump, and constant checking. Or, as you might also remember from the 60's, the goin' up just ain't worth the comin' down!

Dear Stan, you are of course right. We have seen - and still have... - MCs with VTF around 1.2 to 1.5 (v.d. Hul among others). MC do NOT have ad decretum lower compliance than MMs. The skating force is - among others - a result of VTF, offset of the stylus towards the groove wall and total contact area of the stylus. Its becomes less with increased effective length and resulting decrease of tangential error. It is null at any zero error point and becomes more and less with increasing tangential error and decreasing to wards the next zero point.
Simple model.
The force is never constant - and should therefor be addressed by an inverse force which is itself variable in conjunction with the tangential curve of the given tonearm.
Not really complex - it just needs more than a plain stupid constant anti-force.
But nothing in our days is so clear as not to be neglected and denied by some.
I am positive that maybe Raul in his new upcoming tonearm-design will address this issue.
Of course we can always simplify things and we see a strong movement in this direction ever since the last 2 generations.
Why ?
Because it makes things cheaper to produce.
More profit made - less brain needed.
Simple story indeed.

Stan, the Supex cartridge(s) you specifically refer to, have elliptical styli. In fact, Supex makes cartridges with either spherical or elliptical styli - no line contact styli! AND they all have medium compliance suspensions, and some even have high compliance suspensions, just like most MM cartridges. Add to the elliptical stylus, a recommended VTF of 1.8 gm and you have a recipe for high skating torque. So from an anti-skating adjustment point-of-view, those Supex are indeed more like MM cartridges. So I think you need to do your homework before making general assumptions like you did.

I also think it's a bad idea to assume, as some others here do, that there is such a level of complexity at work in this situation, that all efforts at resolution are hopelessly doomed. If one understands the basic forces at work, and especially their overwhelming magnitude compared to the little molehills some want to make into mountains, (to prove how smart they are?) it's really a simple matter to cancel 90% of them out. If you want better than that, as I said, get a straight line tracking tonearm.

As for implementation, would you rather have a 'simple' German car or a 'complex' British car? Hmmmm . . . . . ?
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Dertonearm,

I do not understand why you assert that skating force is "null at any zero error point". If you're saying that skating force is null at points of zero tracking angle error (e.g., at the Baerwald or Loefgren points), that is simply untrue.

Skating force exists ANY time the axis of the cantilever is not aimed directly at the pivot point of the tonearm. Therefore, EVERY tonearm with a fixed pivot point and an offset cartridge mounting angle encounters skating force at all points that the stylus is riding on a spinning record.

Don't take my word for it, and let's not argue theory. Just try this simple experiment: find a record that's ungrooved (flat) at the null points of your particular alignment scheme. Set A/S to zero, spin up the record (the faster the better) and drop the stylus at one of the null points.

Unless you're using a linear tracker or a pivoting arm with no offset angle I guarantee it will "skate" inward.

Once you've performed this simple experiment you will revise your theory, because it doesn't meet observed phenomena.

If I've misunderstood your assertion, please explain in other words if you can. I fear your current assertion is potentially misleading for the less experienced.

Hi,
anti-skate force is a ~99% function of the OVERHANG!... have I been missing something?!

Without overhang, no vector force, no skating force.
If you had "underhang" you'd create a vector force once again, but it is not of practical interest other then in the consideration of the vector forces.

Axel