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

There are three parameters involved: spindle to Pivot distance, pivot to stylus distance, and offset angle of the cartridge. Once two are set the only thing that can be changed is the third. Often the spindle to Pivot and the offset angle are set so that leaves only the pivot to stylus that can be adjusted. I really like the feickert alignment tool. It is pretty much Universal and has calibration marks for the various schemes.

This sidebar about mounting distance is irrelevant. SOTA built a custom armboard so the suspension will balance properly and drilled that 222 mm as per factory specs. 

Why must I have the Wallyskater, if I have both a Smartractor and a Feickert protractor? To set AS? Or what?

@lewm : Yes, WallySkator is just for anti-skate. It enables an easy setting to a requisite percentage of VTF, which JR, or perhaps Wally before him, established to be 11% for 9-inch arms, 9% for 12-inch. It does some other things, too, like measure stiction, but AS is its main use.

At best, any AS setting can be correct (exactly equal in magnitude to the skating force) at only two points on the LP surface. There is a fairly broad range of settings that will satisfy that requirement, 11% of VTF being one of them. I’d be curious to borrow a Wally just to find out how close I get to 11% by simply setting AS to a minimal value above zero .