Peter,
Sorry for spouting theory and forgetting a few straightforward examples.
First I never use a magnifier or loupe for VTA/SRA, at least not any more.
For a ZYX I just make the ridge near the bottom of the cartridge body level. I know from experience that this will get me very close - on any tonearm.
For a Shelter I just make the cartridge body slightly tail down. I know from (less) experience that this will get me close - on any tonearm.
If I'm setting up an Ortofon A90 with Dan and you at Chris's house I waste 45mins trying without success to decipher and follow the instructions about adjusting SRA under magnification. ;) Then I come to my senses, level the cartridge frame by eye (30 seconds) and find that we're so close I can nail the sweet spot by ear on any LP in another 30 seconds. This worked on both the Durand Talea and the Kuzma Airline, easy as pie on both arms.
That last example is how I (should) begin with any unfamiliar cartridge. Fussing with magnifiers to nail SRA certainly works and is technically the most accurate way to start, but since one must fine tune by ear anyway it just isn't worth the time and expense, IME.
It's not that levelling the armtube is bad. It should get you *nearly* as close as levelling the cartridge body. It's just that people with less knowledge and experience than you read these threads and may get the wrong idea about what they're trying to adjust. Whether one's eyes are good enough to see the (obviously smaller) cartridge body vs. the armtube is of course an individual matter.
Sorry for spouting theory and forgetting a few straightforward examples.
First I never use a magnifier or loupe for VTA/SRA, at least not any more.
For a ZYX I just make the ridge near the bottom of the cartridge body level. I know from experience that this will get me very close - on any tonearm.
For a Shelter I just make the cartridge body slightly tail down. I know from (less) experience that this will get me close - on any tonearm.
If I'm setting up an Ortofon A90 with Dan and you at Chris's house I waste 45mins trying without success to decipher and follow the instructions about adjusting SRA under magnification. ;) Then I come to my senses, level the cartridge frame by eye (30 seconds) and find that we're so close I can nail the sweet spot by ear on any LP in another 30 seconds. This worked on both the Durand Talea and the Kuzma Airline, easy as pie on both arms.
That last example is how I (should) begin with any unfamiliar cartridge. Fussing with magnifiers to nail SRA certainly works and is technically the most accurate way to start, but since one must fine tune by ear anyway it just isn't worth the time and expense, IME.
It's not that levelling the armtube is bad. It should get you *nearly* as close as levelling the cartridge body. It's just that people with less knowledge and experience than you read these threads and may get the wrong idea about what they're trying to adjust. Whether one's eyes are good enough to see the (obviously smaller) cartridge body vs. the armtube is of course an individual matter.