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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
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rauliruegas
13,048 posts
 

@dover  : No, that was finger error.

Even that the calculations for the P2S 222mm shows at that firstlink I posted and the EL calculations shows 239.3 for that P2S. Numbers says that's the correct EL not 239mm., numbers are numbers/mathematics.

 

OLsays in his site:  " Centre of mounting hole to centre of platter should be 222mm (plus or minus 1mm tolerance). "

It's not talking of overhang.

Now, if the P2S distance change to 221mm or 223mm over calculations at the same time changes the overhang and offset angle and the main target for any tonearm owner is to make the tonearm/cartridge/TT alignment with Accuracy and this is what I'm talking about.

Anyway, that 239mm or 9.5" stated by OL can't be achieved with the OL information.

So other that my finger error I think I'm not wrong.

Maybe what created some kind of confusion in my posts was that my " error "I wasthinking that the OPwantsit 17.5mm as overhang.

 

" Apparently you think its fine to set up tonearms with an accuracy of +-0.3mm "

 

You did it not me,so don't put words in my mouth.

 

R.

 

 

 

 

mijostyn's avatar
mijostyn
8,570 posts
 

@lewm you know I meant the wavelength of the tracing, obviously the wavelength in air does not change.

dover
2,243 posts
 

" Apparently you think its fine to set up tonearms with an accuracy of +-0.3mm "

You did it not me,so don't put words in my mouth.

Actually you suggested mounting the arm 3mm out of manufacturers specs.

Here is your actual post.

 

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rauliruegas

12,992 posts

 

@dover : No it’s not wrong because OL says a margin of +,- 2mm. In the other side we can change those numbers with out any negative consequence because 225 means longer EL and les distortion.

The manufacturers specs are 222mm - you are suggesting mounting it at 225mm.

That would mean pushing the cartridge out further, significantly increasing the effective mass and inertia of the tonearm beyond what the designer intended.

It's no wonder you have suggested your 1980's CD player is more accurate than your turntable system.

Given that you have been trying to build your own tonearm for the past many years, perhaps you could now focus on a design with an effective length of 48 inches - according to your theory that would sound fantastic - even lower distortion. Pity the poor cartridge though, trying to cope with such vast effective mass whilst navigating  eccentric records.

 

lewm
13,001 posts
 

Dover, I’m not quite sure what the argument is really about but my calculations suggest that a change in EL from 222mm to 225mm would increase effective mass by only about 2%.

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