I agree with VdH's first sentence, but not with the main part of his answer. "Arm base always higher" may work for his cartridges but it won't necessarily work for others. It certainly doesn't work for mine.
The fallacy here is focusing on armtube angle. VTA is the angle subtended between the cantilever and the record surface when normal downforce is being applied. This angle cannot be predicted from the armtube angle without knowing the cartridge and the VTF.
Some cartridges are taller than others. Some cartridges have different cantilever lengths and angles than others. Some cartridges have softer suspensions than others. All these factors directly affect VTA and the armtube angle needed to achieve it. In short, armtube angle is derivative from VTA, not a predictor of it.
Setting VTA by focusing on armtube angle will only work until you change cartridges or VTF's. One could even argue that as a cartridge's suspension breaks in and softens with age that a slow increase in arm height will be needed to compensate.
In the end, setting arm height by any visual means is an approximation. All it can do is get you in the ballpark. After that, setting by ear (or with test equipment for the very dedicated) is required for optimum performance.
The most accurate visual methodology is explained in Jon Risch's "VTA once and for all" thread in the FAQ's on VA. But since visual adjustment is only approximate I find that a bit of overkill. For a quick roughing-in I just ascertain how other people play the cartridge (nose up, nose down or - usually - level) and adjust by ear from there. Neither of these methods has anything to do with the armtube angle.
I agree with VdH that different records need different arm heights, though adjustments of far less than a mm are required for some listeners. Aside from differences in thickness, not all record manufacturers adhered to the industry standard for VTA. We adjust arm height for each record, so each record jacket has a yellow sticky (or two) with notes on arm height for every cartridge that record has been played with. This lets us dial in arm height while the platter is spinning up, so there's little or no loss of time.
The fallacy here is focusing on armtube angle. VTA is the angle subtended between the cantilever and the record surface when normal downforce is being applied. This angle cannot be predicted from the armtube angle without knowing the cartridge and the VTF.
Some cartridges are taller than others. Some cartridges have different cantilever lengths and angles than others. Some cartridges have softer suspensions than others. All these factors directly affect VTA and the armtube angle needed to achieve it. In short, armtube angle is derivative from VTA, not a predictor of it.
Setting VTA by focusing on armtube angle will only work until you change cartridges or VTF's. One could even argue that as a cartridge's suspension breaks in and softens with age that a slow increase in arm height will be needed to compensate.
In the end, setting arm height by any visual means is an approximation. All it can do is get you in the ballpark. After that, setting by ear (or with test equipment for the very dedicated) is required for optimum performance.
The most accurate visual methodology is explained in Jon Risch's "VTA once and for all" thread in the FAQ's on VA. But since visual adjustment is only approximate I find that a bit of overkill. For a quick roughing-in I just ascertain how other people play the cartridge (nose up, nose down or - usually - level) and adjust by ear from there. Neither of these methods has anything to do with the armtube angle.
I agree with VdH that different records need different arm heights, though adjustments of far less than a mm are required for some listeners. Aside from differences in thickness, not all record manufacturers adhered to the industry standard for VTA. We adjust arm height for each record, so each record jacket has a yellow sticky (or two) with notes on arm height for every cartridge that record has been played with. This lets us dial in arm height while the platter is spinning up, so there's little or no loss of time.