Feel Silly Asking This Question Alignment Parameters

@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.

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, 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.

I agree with all you say above, but I just wanted to point out that increasing (what I thought was EL but my in fact be P2S) from 222mm to 225mm has little effect on effective mass, which of course has nothing to do with alignment per se. If we are actually talking about P2S, then the net effect on effective mass of the commensurate increase in EL would be even less than 2%.  But for EL, if effective mass was 20g at 222mm, it would be ~20.4g at 225mm. (This is very inexact, just comparing the square of the two numbers, which is directly proportional to effective mass.) 

Looking back on my nearly 50 years in this hobby, I would unashamedly say that there are some things I did wrong for 40 of those years, some other things that I did wrong for 30 years, and some more unknown things that I am doing wrong even now.  (Not speaking only of tonearm alignment.) For the uninitiated or newbies, they should know it's a marathon, not a sprint to get to audio Nirvana.  But such is our capacity for self delusion that one can enjoy the hobby from the get-go, just keep an open mind and hope to get better at it.

@lewm : Well said.