Feel Silly Asking This Question Alignment Parameters


I feel silly asking this question, but here it goes. Most of the arms I have owned over the years have came with proprietary protractors, and certain ones like the SME are really just overhang gauges. For other ones I have bought custom generated arc protractors for the specific arm. I will probably do so again with this Origin Live arm. However in the mean time i decided to set up using their provided protractor. 

When I went to install a cartridge on the table, I found I was not wild about using their protractor, so I decided to generate a Conrad H arc protractor till I made an order for an Accutrak one. What I found odd is that Lofgren A had the longest overhang at 16.8 mm and  Lofgren B at 16.3mm. The Origin Live shows 17.5 mm. Is the Rega type alignment that much different than Lofgren or Stevenson? I also noticed with the OL alignment that cartridge offset in the headshell was noticeably greater. 

What is also noticeable is the sonics of each alignment is different. To be honest, I like the overall sound of the OL alignment, but I also have this nagging feeling that it does not track as well. 

 

I always felt at this stage of my audio journey I knew how to align a cartridge. I have been doing it since I was in my 20's! Now I have a large degree of uncertainty of which alignment to choose, and what the implications are if i choose wrong. This arm is a long term keeper for me, so its a matter of wanting to get this set up optimized. 

 

Any insights you might pass along is greatly appreciated. Do have a good chuckle at my expense as it seems that I get into these moments of self doubt, and trying to find the way out of the forest of audio can be quite comical. 

neonknight

@thom_at_galibier_design Welcome Thom.

I am a big fan of Frank Schroeder. I currently run a CB. The method of setting AS recommended by Frank and Peter is useful for people who have no better way. The problem is defining what a "slowly drift" means. One person's slow drift may not be another's. From a tracking and record wear perspective too little AS is just as bad as too much. The determinants of the skating force are VTF, contact patch size, groove velocity and modulation density. The skating force increases towards the center of the record because the modulation density increases. For any one particular set up VTF and Contact Patch are constants. With a reasonably compliant cartridge like a Lyra or Van den Hul you can determine the correct AS force by careful observation of lateral cantilever deflect as the stylus settles into the groove at the midpoint of the record. Bright light and 10X loops help. The cantilever should not move laterally from its resting position. This corresponds to a Wallyskater reading of 12 % for really acute styluses like the replicant 100, Gyger S, Soundsmith MR and Jico SAS. More conservative line contact styluses, like Lyra and My Sonic Lab use, correspond to a WallySkater reading of 11%. Even though groove velocities can vary from one record to another, there is little difference in the AS required from one record to another. This problem exists for any method of setting AS. 

Having gone through the above process many times I have no problem trusting the WallySkater. It is a rapid and easy way to find a reasonable, average AS setting and definitely more accurate than a "slow drift" towards the label in the run out position. I know exactly what 11% means. 

@thom_at_galibier_design 

I forgot to mention, the cure for improper zenith or any other stylus orientation problem is a new stylus or cartridge. IMHO every cartridge should be examined before it is mounted for the first time. If the stylus is not mounted correctly it should be covered under warranty and usually is without argument. Under optimal circumstances the examination should be done before the cartridge leaves the retailer. A file of the pictures should accompany the cartridge. Most individuals are not going to spend $1500 on a usb microscope and proper staging. 

@cundare2

NO ONE who is serious about vinyl reproduction should try to fool themselves into thinking that they can accurately and precisely align a commercially manufactured cartridge without WAM on their side.

I could not agree more. I went all in with analysis, tools and support from JR for a new TT and Cart (maybe end game). At this level you really are wasting money without WAM.

 

bill_k, Can you direct me to Peter Ledermann’s quote as follows: "With all due respect you [referring to me, Lew] stated that "AS is constant in magnitude" which is not true. As Peter Ledermann confirms: "A properly designed anti-skating is non-linear, as it should of course increase A-S automatically as the cartridge approaches the inner grooves."

This stimulated me in several directions. First, it may have been flippant of me to say that AS is constant in magnitude across the LP surface; I should have thought about it in greater detail, but if you consider an old-fashioned string and weight AS device, what would change the magnitude of AS force as the tonearm swings in toward the platter is the angle of the pull of the string/weight on the arm wand, assuming that friction of the string on the guide is unchanging. That changing angle would indeed probably change the magnitude of AS, but such a change would be linear with a slope related to the changing angle of the pull force. That still does not mimic the ups and downs of the skating force. The AS force exerted by a magnetic device would also vary but also would not closely mimic the changes in skating force that occur in the course of playing an LP using a pivoted overhung tonearm. Finally, I wish I knew what tonearm Peter was thinking of when he wrote that passage. Finally, finally, is it indeed true that the max skating force occurs at the innermost grooves? Gotta think more about that one, but off the top of my head, the skating force would be related to the headshell offset angle at the innermost null point (a minimum) and then rise as the stylus approaches the runout grooves. Before the tonearm reaches the innermost null point, the skating force is created by headshell offset angle PLUS TAE. At the outer null point, it is again caused only by headshell offset. And at the outer grooves, again we have both TAE and offset. There is just no way to design an AS device to follow those variations, and this does not even take into account groove tortuosity as another ever changing source of a skating force.

@lewm - Just happened to catch your post, but for future posts directed to another user you should use @username so they'd be notified. I had to do some searching to find where I sourced that quote from Peter but got it. It's on the following page in the "There's More..." section. https://www.sound-smith.com/faq/how-do-i-adjust-anti-skating-my-cartridge He covers many of the important aspects of AS there.