Anti skate. I think something's wrong

DougDeacon wrote :

"In a discussion of A/S settings, the forces generated by eccentrically drilled LPs are merely a non-sequitar, since no A/S device compensates for them. ;-)  "

Hardly non-sequitur, Doug! The context is that anti-skating force causes "audible stress" on the suspension.

Lateral movement due to mis-drilling also causes suspension stress (continuous but alternating) whether it is possible to compensate or not?

As you know, even well-optimised A/S doesn't truly "compensate" for all operational conditions because skating is a constantly moving target.

To describe skating force as constantly changing and therefore any setting will be imperfect, is accurate but deceptive.  It is accurate that skating varies with groove velocity and offset angle, but deceptive to apply the word perfect to the physical playing of a phonograph record.

I don't adjust AS by seeing how the stylus behaves in a blank groove. That seems pretty stupid.  If you observe the cantilever from the front while your "typical" music is playing, and repeat this observation, you might get an idea of the error your headshell position is to the centering of the cartridge.  In a perfect world your cantilever should be centered over the groove.  Antiskate is a force applied to the arm in an attempt to do just that.

What is groove velocity?  The velocity of stylus deflections (bouncing off side walls) in-groove. Since the groove is constantly moving it's the job of the arm to be both a stable platform for the cart and a perfect follower of the groove as it moves toward the spindle. Why the uneven tip wear if such is the case?  Having a poorly centered cart is to encourage channel imbalance - uneven cantilever deflections with respect to L and R. 

If someone hasn't heard channel imbalance due to AS, then they've been using heavy trackers or lack powers of observation. This is obvious with low VTF carts where channel imbalance is more dramatic and immediate. I think you'll find, there is no completely right answer.  With lower cu carts you're choosing between physical centering and increased torsional affects on the cantilever from AS.  

fleib

Dear Fleib,

Regarding your comment on channel imbalance, do you have a flame-proof suit? ;^)

Sorry, my last sentence should have read: 
 With lower cu carts you're choosing between physical centering with increased torsional affects on the cantilever,  or no increase in torsional affects with possible uneven wear.

Moonglum,

No antiskate is a viable option provided VTF is great enough to prevent mistracking. This is not always an option, especially for high cu carts and low VTF.

Look at the physics from a mechanical perspective. You're messing with the pressure on the groove walls by the cantilever/stylus.  I don't know how anyone could miss channel imbalance with a high cu cart.

Regards, 

Dear Fleib,

No worries.

Yes, it’s interesting to get a general overview of how successful folk are at keeping VTF within reasonable limits. Most people tend to live at the top end of the spectrum. Sometimes this is because others recommend it or perhaps because they’ve used Test Tones resulting in a "maxxing out" of A/S.

Indeed there is a minority "Cult of Excessive VTF" (i.e. beyond the manufacturers recommendation or max limit) which is not always discouraged by manufacturers on the grounds that the customer is always right (Why argue? Whatever makes them happy!) ;^)

Now, I’m not saying that any of our illustrious "zero A/S" contributors here are getting anywhere near that level of VTF in their quest for zero anti-skate just that there are others out there compensating for different reasons.

For the benefit of those who may be misled into maxxing out on VTF (or over-Maxxing) we should publish the standard warning that VTF increases skating force and thereby unilateral wear on the diamond. There is a price to pay...

Don’t know if you’ve tried the following experiment? Several years ago I performed multiple needledrops of one side of an LP, bracketing the optimum A/S setting ranging from “A/S max” to a setting below the optimum. Then I was able to rapidly switch between them on an HDD running them effectively in parallel with each other.

(This of course assumed that VTF should be identically/ideally "mid-range" for all needledrops.)

As you quite rightly say, changes in general balance between each setting are clearly audible (whether there is an actual voltage amplitude difference is contentious for some). Subtle though the differences are when AB-ing, what was interesting about this was that listeners didn’t hugely dislike any of the settings but would eventually arrive at a preference with some difficulty.

On the other hand, doing a similar experiment "the hard way" by adjusting the T/T then using a fading musical memory of the programme material to compare will of course still work, albeit less successfully because few people want to wear out the same snapshot over & over again on an LP, so for the purposes of comparison it’s undeniably easier & quicker to switch between samples and instantly replay on an HDD.

One of the rare advantages of digital technology...it’s consistent. ;^)