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

@tony1954 The Alignment Protractor that is generated includes 190 mm vertical and horizontal distances that you measure after printing and then you adjust the scaling on the web page and generate another protractor and remeasure etc..  I have had no problem getting them within 0.1mm which is a negligible error over 190mm.

@tony1954 And if there is any distortion within the page I haven't seen it but I don't think there is any way to adjust for that.  But honestly, 1/32nd of an inch over large distances doesn't seem like a concern to me.  If there was that much distortion in the "grid" that is printed I imagine that would be visible and it isn't.  

I have an aluminium Dr. Feickert protractor that I only use to measure spindle to pivot distances but now I wonder if I should worry about how much it expands and contracts with temperature changes LOL.

@mijostyn : Good but we are not talking on LT tonearms.

 

Returning of the kind of alignment you prefer next is what an expert about ( no ofense to your knowledge level in anyway ) :

 

 

" Löfgren suggested an alternative alignment in his 1938 paper, which calls Löfgren B, but its raison d’être is different. It gives the result shown in fig.11, from which you can see that it lowers distortion over the middle portion of the disc at the expense of higher distortion toward either groove extreme, particularly the end of the disc side—an approach that just doesn’t make sense to me: "

 

That fig. 11 is similar to the graphs in VE calculator.

 

R.

I don't know why you folk don't read the manual.

@neonknight

Origin live Agile ( standard 9.5" arm 239mm ) has a recommended pivot to spindle distance 222mm.

Overhang for Baerwald A is 17.3mm - offset 22.99

Overhang for Baerwald B is 17.75 - offset 229.94

If you have mounted your arm with a different pivot to spindle then the numbers change.

Rega arms use Stevenson, Origin live appears to designed for Baerwald A based on. their recommended offset angle.

 

@rauliruegas Appreciate the numbers from Vinyl Engines calculator. I used to have an account there, and then one day I could not log in. Never could reestablish access to it, nor make a new one.

The arc protractor program I used was Conrad H one, as it is reported to be an acceptable one. The system only allows input of spindle to pivot and the print ratio is 1.0

What is odd is the numbers do not match up. For Lofgren B as example the overhang is 16.8 mm, but the inner and outer nulls are slightly different. 57.4 and 114.8 and an offset angle of 22.4 If the program is using the same calculations I would not expect such a variance in numbers.

With what the Vinyl engine calculator shows, I think I will order an Accutrak arc protractor for this arm.