Swampwalker pointed out the importance of Eyeball-to-Stylus distance, which is critical but often, umm, overlooked! Like him, I wear progressive lenses. Unlike him, I am quite nearsighted. Being able to see even the smallest styli from an E2S of 5" or less is helpful. Of course I need a hand finding the turntable...
I've never used an arc protractor and don't feel a particular need for one. All my tonearms have allowed for overhang adjustment in the headshell and I've never had a problem visualizing which direction to adjust overhang when using a two-point protractor.
To match overhang (and thus eff. length) to whatever pivot-to-spindle distance the arm is mounted at, just check the cantilever angle at each null point. If your eff. length is wrong the cantilever will be swinging through too many degrees or arc or too few (think of it as splay-footed or pigeon-toed, respectively). If the cantilever is swinging through:
- too many degrees of arc (splay-footed), make your eff. length longer
- too few degrees of arc (pigeon-toed), make your eff. length shorter
I know this isn't intuitive for everyone so an arc protractor could be a good solution. My guess is that it would take me longer. I can tweak the position of a tiny cartridge more finely than I can tweak the position of my armboard, so + or - 0.5mm for the arm mounting position works fine for me.
Different strokes...
Re: SME - I know more than one IV/V owner who's drilled out the cartridge mounting holes slightly. Not much, just enough to allow for a degree or two of adjustment to cantilever angle. Seems like a reasonable idea, especially since few cartridges are perfectly made.
I've never used an arc protractor and don't feel a particular need for one. All my tonearms have allowed for overhang adjustment in the headshell and I've never had a problem visualizing which direction to adjust overhang when using a two-point protractor.
To match overhang (and thus eff. length) to whatever pivot-to-spindle distance the arm is mounted at, just check the cantilever angle at each null point. If your eff. length is wrong the cantilever will be swinging through too many degrees or arc or too few (think of it as splay-footed or pigeon-toed, respectively). If the cantilever is swinging through:
- too many degrees of arc (splay-footed), make your eff. length longer
- too few degrees of arc (pigeon-toed), make your eff. length shorter
I know this isn't intuitive for everyone so an arc protractor could be a good solution. My guess is that it would take me longer. I can tweak the position of a tiny cartridge more finely than I can tweak the position of my armboard, so + or - 0.5mm for the arm mounting position works fine for me.
Different strokes...
Re: SME - I know more than one IV/V owner who's drilled out the cartridge mounting holes slightly. Not much, just enough to allow for a degree or two of adjustment to cantilever angle. Seems like a reasonable idea, especially since few cartridges are perfectly made.