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Why use a super accurate cartridge protractor

In discussions about cartridge setup, there are those who say that unless one has a cartridge setup protractor like the Mint, Wally Tractor, Dennesen, etc. one cannot expect to extract maximum performance from your rig. Then there are those that say that even the best alignment tool still only nets you a position that needs further tweaking by ear. In my case, I've used a Dennesen and a number of downloadable free protractors and have been able to get good results with the free downloads if I took my time to make those little .5mm shifts that make sound pop into best focus. Is the superiority of a Mint or a Wally Tractor because one doesn't have to make those final last tiny adjustments? Is it that the mirror surface is easier on the eyes?
photon46
nandric's avatar
nandric
4,086 posts
 
Thekong, The distortions we are talking about are the
opposite of each other. We are of course interested in the least (aka 'minimal') distortion but what about the maximal 'kind'. The so called 'zero points' mean minimal distortion
at those 'points' on the record radius. But there must be
the corresponding max. distortion at some other 'points'.
Well it seems to me that we should worry about those also.
I have never seen any numerical values for those in this forum. It may be the case that while I feel 'proud' about my own selection of the zero points my records are in a
sade state because of my choice?

Regards,
thekong
203 posts
 

Hi Nandric, I agree with you that we should also worry about the max. distortion, actually maybe more so than the min distortion, as it is already quite small.
photon46 OP
1,089 posts
 
Thanks to those who've replied so far, it's been interesting to hear the different approaches and perspectives. Like Stanwal,I think the difficulty of setting dead on correct pivot/spindle distance is something that could use more attention in devising set up tools. I still remain unpersuaded as to obtaining superior results with a Mint vs. less precise methods IF one still has to "make the final adjustments by ear." (Assuming one has properly set up spindle/pivot distance.) In the cartridge setup instructions with the Vacuum State Guru protractor, Allen Wright says that after checking many cartridge alignments with final adjustment tunings done by ear, there is a consistent trend of finding settings about 1.27mm behind traditional Cotter points on an alignment arc. After spending part of last Sunday setting up an Ortofon Kontrapunkt H with a super fineline stylus, I ended up very close to those points myself.
dertonarm
1,042 posts
 
Dear Thekong, dear Nandric, we should in specific worry about where on the groove's radius the maxima and minima are located. The groove's walls do change with decreasing radius and thus do the conditions for the stylus' polished areas. Thats why high derivations from the tangential zero are most "lethal" to the sound towards the inner label.
Cheers,
D.
thekong
203 posts
 
Hi Dertonarm, if I understand correctly, the alignment you chose aimed at minimizing distortion at the last 1/3 of the groove’s radius, which I think make a lot of sense, as the inner tracks are inherently harder to track, and in addition, many of the classical pieces have the climax towards the end.

What I wonder is the need for ultra precision in the alignment. If I am using a 9” arm, and misalign by, say 0.5mm, then how far would the null points shift?

Best regards,
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