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

The overhang difference between 16.8 mm and 16.3 mm is inconsequential. Even 17.5 mm is not critical. I doubt you can hear the difference from any of these. 

+1 on the SmarTractor - I swear by it.  It costs ~ $600, but totally worth it. Might be able to find a used one for less if you're not in a hurry.

 

Whether you can hear a difference or not, even an 0.5mm error or greater in overhang, provided you don’t also alter other standard parameters, certainly CAN make a drastic difference in locating the two null points, or even whether you actually get two null points anywhere on the playing surface of an LP. This has been demonstrated, probably by Dave Slagle, but I can’t find the reference.

@lewm Makes the most reasonable post. No other post explains the reason behind a 17.5 mm overhang. I must be missing something but this does not match any geometry for an arm with a spindle to pivot of 222 mm.