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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
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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rauliruegas
13,048 posts
 

@dover : It's curious/negative that you took from my posts only what ssome way or the other you can use as a weapon.:

Iposted this information that came from VE but maybe you don't read it or let pass on purpose:

 

" 

 " This document is reproduced here by kind agreement of Mark Baker at Origin Live. "

 

" Rega arms and Origin Live arms require mounting dimensions such that the centre of the platter to the centre of arm hole is approx 223mm plus or minus 2mm tolerance and the hole diameter for the arm is 24mm to 25mm. "  

So that's not my information, I only pasted and used.

 

R.

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rauliruegas
13,048 posts
 

Dear @neonknight  : According the OL information you can make the alignment with that 9.5"  El and this is what you can get and could be the best orthodox alignment shot:

 

https://www.vinylengine.com/tonearm_alignment_calculator_pro.php?arm1=Arm+1&l1=el&a1lv=241.3&a1=la&oh1v=&oa1v=&arm2=Lofgren+A&l2=el&a2lv=241.3&a2=la&oh2v=&oa2v=&arm3=Lofgren+B&l3=el&a3lv=241.3&a3=lb&oh3v=&oa3v=&arm4=Stevenson&l4=el&a4lv=241.3&a4=st&oh4v=&oa4v=&rs=12&rsv=&og=iec1&ogv=&ig=iec&igv=&cal=y&submit=calculate

 

R.

 

 

dover
2,243 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%.

@lewm 

The OP wants to use an ARC protractor.

As I pointed out earlier, changing the effective length means a different ARC protractor will be required. This is likely lost on many readers.

Unfortunately for many readers who struggle to understand how to set up a TT properly, arbitrarily changing the pivot to stylus distance outside of the manufacturers specifications could lead to disaster in terms of reasonably accurate set up.

You might be quite comfortable with this because you have many years of experience setting up TT's. Unfortunately most don't.

The whole purpose of the OP's question was to address concerns that he had on set up. The word and numbers salads tossed up in this thread - encouraging others to ignore manufacturers guidelines - is a recipe for disaster.

Whilst you might be happy with this, because you enjoy intellectual debate, the reality is, for newbies, confusing them often leads to frustration and disappointment.

Consequently we lose another turntable enthusiast.

Why do we care about folk losing enthusiasm for turntables - well, in a dwindling market, prices rise, the market shrinks further and eventually innovation declines and the market dies.

Have a look at the declining numbers on this forum.

Therefore as you and I and some others on this thread have over 30 years of experience in setting up turntables - it is incumbent on us to help folk with their turntable set up advice by keeping advice simple, accurate, and explain in a way that is easily understood.

 

 

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