Set Overhang on arm w/adjustable tracking angle

Doug, if the screw holding the cartridge mounting plate is directly above the stylus, would rotating the cartridge change the overhang? I follow your post and it makes sense to me in every case except the one I mention.

It seems to me that if the cartridge is being rotated along a zenith axis which corresponds precisely with where the stylus tip meets the LP, overhang becomes determined only by the position of the arm pivot point.

I find cartridge zenith alignment to be one of the key advantages of the Mint LP protractor. It is very easy to align the cantilever with the tangent lines at the null points.

Garibaldi,
Doug has has given an excellent summary. The only point I would make is that your arm should have 17.31mm overhang not 14mm.

Peter,
It is interesting that few of the current arms with the facility to rotate and slide the cartridge choose to do as you suggest. It seems an obvious design advantage, particularly if the two movements are kept separate. It is, of course, simpler and cheaper to combine the two functions on a bar between the cartridge mounting holes.

John

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Peter,

Good thought. If one is lucky enough to have a cartridge whose stylus falls directly beneath the axis of rotation of the tonearm's mounting plate, rotating the cartridge would not affect overhang/eff. length. Unfortunately (as I'm sure you know), there's no standard for cantilever length, so having this happen is a matter of luck.

Fully agree on the advantages of the Mint for zenith alignment. No protractor I've used comes close in this regard (a Wally might, but I've not used that one).

John,

Sadly, a tonearm designer has no way to predict where a stylus will fall relative to the mounting hole(s). Cantilever lengths vary from one cartridge to another.

Doug,
I know there was a large variation in that cartridge dimension in the "good old days" but I was under the impression this had more or less standardised on 9.5mm. So aligning the pivot to that dimension on the assumption it will be within a mm or two must introduce less error by almost a factor of 10 when rotating the cartridge than if the pivot is 9.5mm away.

A facility for an adjustable pivot to stylus distance together with a cartridge mount that only rotates is another way to do it to avoid the two settings interacting. But then an arc protractor couldn't be used. It would have to be one based on the Dennesen principle or a standard two point.
John

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Thanks for all your responses. They have confirmed my suspicions of how to align the cartridge. Here's why I was confused: The arm and turntable I have included the Clearaudio protractor, but there were no instructions for using it. I was confused because it only has a single null point printed on it.

Recently, I learned that I was missing the instructions for the protractor. There is no mention of its use in the instructions for setting up the arm. I found a manual online for the Unify arm which described the way to set up the protractor. Essentially, there are two lines within which you align the wand. Then you set up the cartridge at the single null point as you do with any arm. Why there's only one null point, I can't say.

Set up was finicky, for sure, but I got everything lined up properly and proceeded to trash the tip of the cartridge. First time that's happened in 40 years! So, one cartridge to Soundsmith and a spare installed.

All's good. Thanks again for all your help.

GP