On anti skating

[Nat]

I don't believe that the characterization of the AR arm as high mass and high friction is accurate -- it is true that the counterweight isn't decoupled, and that might cause the resonance to be more pronounced, but the arm tube and headshell aren't very massy, and though the arm bearing doesn't use ball bearing races, I think it is fairly low friction since the shaft travels in a film of oil.
I also think that the Grace arm is misnamed. My 747 is a low mass gimballed arm and has antiskating, as do most Graces other than perhaps early ones.

 

[gusten]

Anyone interested might want to query Harry Weisfeld, owner and founder of VPI, who does not care much for anti-skating. He says he can hear it working. No question on a warped record anti-skating might be audible. Anti-skating can be avoided by adding a bit of vertical tracking force. Say add ~ 0.25 grams. I believe the comment relating to lighter tracking forces has merit, but would caution that every stylus that I have ever examined used on a arm without anti-skate has worn unevenly, with more wear on the inside of the stylus than on the outside. Too, I have records in my collection that were played originally on Weathers (i.e. very lightweight wood tone arm, no ant-skate) others records on my first "upgrade" AR (high mass, high friction arm, no anti-skate), others on my next "upgrade" Dual 1219 (low mass arm with anti-skate), later on a Thorens TD125 first with Rabco SL8R (medium mass tangential tracking arm) and later SME 3009 Series II and...well I could keep going but you get the idea. Playing my old records again, some hadn't been touched in years, provides insight into what different record wear patterns have occurred with different equipment. Generally, I can say that the records first played on anti-skate equipped arms (as well as SL8E) seem quieter and show less wear. By the way, today I own a Wild-Heerbrugg microscope and regularly check stylii for wear. Additionally, years ago during the 1970s I was in the business and as such set up a lot of turntables and examined a lot of cartridges in addition to my own. So these comments are more than just anecdotal.

Yes, if we do a reasonable caculation of groove wall forces for a normal cartridge using a VTF of 2gF, normal friction (0,3-0,35) and 22-23 degrees offset angle, the normal forces between walls will be quite different, if not using AS.

The outer wall will be subjected to 1,0-1,1gF, while the inner wall will have 1,7-1,8gF. So there is certainly a reason for AS, and why the needle will wear non symmetrical.

 

[marcmorin]

I don't believe that the characterization of the AR arm as high mass and high friction is accurate -- it is true that the counterweight isn't decoupled, and that might cause the resonance to be more pronounced, but the arm tube and headshell aren't very massy, and though the arm bearing doesn't use ball bearing races, I think it is fairly low friction since the shaft travels in a film of oil.
I also think that the Grace arm is misnamed. My 747 is a low mass gimballed arm and has antiskating, as do most Graces other than perhaps early ones.

the original calc'd EM mass of an AR arm is 9gr. In original functioning condition both vertical and horizontal bearings were oil damped. The vertical with silicone, the horizontal with oil. The coupled C/W aids in reducing longitudinal waves by providing a point of termination for that wave front.


https://www.youtube.com/watch?v=Lq2Rk7_i6hQ

Although the video is about checking the freedom of bearing movement, it also shows a basic issue in most arms, and that is the potential energy due to mass offset around the vertical pivot. You'll notice the arm swings radically to the right.

 

[Bill Stevens]

I don't believe that the characterization of the AR arm as high mass and high friction is accurate -- it is true that the counterweight isn't decoupled, and that might cause the resonance to be more pronounced, but the arm tube and headshell aren't very massy, and though the arm bearing doesn't use ball bearing races, I think it is fairly low friction since the shaft travels in a film of oil.
I also think that the Grace arm is misnamed. My 747 is a low mass gimballed arm and has antiskating, as do most Graces other than perhaps early ones.

You are entitled to believe what you want. The AR turntable had a lot of merit in the day, except for the limitations imposed by the arm. My AR turntable is long gone, but many of the records I bought at the time and still own offer an indictment of that arm. YRMV, but I doubt it. I set up a lot of AR turntables when it was current and popular and examined the stylii used with them on a routine basis. Let me just say that the AR arm wore stylii and records faster than probably any other popular arm of that era. In fairness the best arms were on more expensive turntables of course. The AR turntable was a screaming deal and it did some things amazingly well and it taught the world how to suspend and isolate the rotating parts from the stationary parts to avoid acoustical feedback. Full points for it's good features. The arm was the weak element.

 

[AvFan]

I am trying out a different cartridge on my SP-25/Audio Technica ATP-12T (no anti skate) and I may be hearing the effect of the "skating". I found this description of what you'd hear without some form of anti-skate and it matches what I hear with the AT:

"Adjust the skating force to zero and prepare yourself for a mean experience. The right channel will not show dynamics at all; it will sit in the corner totally bored and ignoring you. The left channel will sit in its corner like an evil ghost, considering to attack you in the next moment. It will sound very dynamic in a way that numbs the left half of your body. However, the dynamics will be nightmare-like artificial."

The description is dramatized (maybe fitting with Halloween coming up) but does a pretty good job describing what I'm hearing. In this thread http://www.audiokarma.org/forums/index.php?threads/how-does-a-cartridge-fail.682268/#post-9143607 I was concerned that the Grado cartridge on my AR XB was going south because I was hearing much the same thing. The left speaker seemed louder and the right speaker just went quiet but the center image (typically vocals) mostly remained in the middle. I'm hearing the same thing when using the AT arm and the new cartridge.

Am I really hearing the effects of these two arms, the AR and the AT, skating?