SRA is the actual objective. VTA only a method of getting close to proper SRA (lets say 92 degrees, like the angle of the cutter when making the master).
It is a whole lot easier to see the cantilever shaft than seeing the stylus tip, thus VTA of the cantilever is the method of getting close to SRA.
Then you listen, you refine by ear, actually refining SRA. it ain't easy.
Start with cartridge maker's recommended VTA of the cantilever, 15 degrees being common. The end of the cantilever might be bent by design (or see example 3 below), the stylus tip is fixed onto the cantilever at a different angle, to result in achieved 92 degrees.
The tracking force you use will put more or less force on the suspension of the cantilever, (i.e. rubber the cantilever shaft passes thru into the cartridge body, and that will change the VTA, so you need to set tracking force first, and double/triple check your VTA. Change tracking force: check/reset VTA.
Note: suspension could be aged, weak, brittle, .... view the cantilever shaft, not the cartridge body, not the arm.
Three examples:
1. Shure V15 series of cartridges are named for their design of 15 degree VTA.
When new, if manufactured and assembled perfectly, set tracking force, adjust arm height: IF you get the more easily seen cantilever at 15 degrees, then, by manufacturing intent, the stylus tip will be at 92 degrees to the record surface. You are unable to see the stylus tip, but presumably SRA is 92 degrees or close.
2. This Ortofon, VTA 23 degrees yields SRA +/- 90 degrees, then listen/adjust
https://www.ortofon.com/hifi/products/hifi-cartridges/mc-a95/set-up/
3. My Friends Grace, Bent Cantilever (low rider)
His cantilever is damaged, the shaft is bent, the 'low rider' condition, the bottom of the cartridge barely clears the record surface. Factory VTA no longer valid.
It sounded bad, he called me. I came over, saw the bent shaft, stylus not user replaceable. So, until dealt with, what can be done? Checked TT level/spindle/pivot/overhang, all good. Azimuth also good.
a. reduce tracking force to very near minimum, to increase the space between cartridge body and lp surface a squeak.
b. Raised back of arm, increased SRA as much as I could without the front of the cartridge touching the record surface. It's not ideal, best I could achieve, no listening refinement possible, as SRA is a squeak less than 90 degrees.
c. Listen. Much better, even though the shaft is bent, it still responds to groove modulations, it is amazing how good a damaged cantilever can perform IF the Azimuth and SRA are good.
Meanwhile, we found someone in NJ who can fix the Grace Cartridge, off it will go soon.
It is a whole lot easier to see the cantilever shaft than seeing the stylus tip, thus VTA of the cantilever is the method of getting close to SRA.
Then you listen, you refine by ear, actually refining SRA. it ain't easy.
Start with cartridge maker's recommended VTA of the cantilever, 15 degrees being common. The end of the cantilever might be bent by design (or see example 3 below), the stylus tip is fixed onto the cantilever at a different angle, to result in achieved 92 degrees.
The tracking force you use will put more or less force on the suspension of the cantilever, (i.e. rubber the cantilever shaft passes thru into the cartridge body, and that will change the VTA, so you need to set tracking force first, and double/triple check your VTA. Change tracking force: check/reset VTA.
Note: suspension could be aged, weak, brittle, .... view the cantilever shaft, not the cartridge body, not the arm.
Three examples:
1. Shure V15 series of cartridges are named for their design of 15 degree VTA.
When new, if manufactured and assembled perfectly, set tracking force, adjust arm height: IF you get the more easily seen cantilever at 15 degrees, then, by manufacturing intent, the stylus tip will be at 92 degrees to the record surface. You are unable to see the stylus tip, but presumably SRA is 92 degrees or close.
2. This Ortofon, VTA 23 degrees yields SRA +/- 90 degrees, then listen/adjust
https://www.ortofon.com/hifi/products/hifi-cartridges/mc-a95/set-up/
3. My Friends Grace, Bent Cantilever (low rider)
His cantilever is damaged, the shaft is bent, the 'low rider' condition, the bottom of the cartridge barely clears the record surface. Factory VTA no longer valid.
It sounded bad, he called me. I came over, saw the bent shaft, stylus not user replaceable. So, until dealt with, what can be done? Checked TT level/spindle/pivot/overhang, all good. Azimuth also good.
a. reduce tracking force to very near minimum, to increase the space between cartridge body and lp surface a squeak.
b. Raised back of arm, increased SRA as much as I could without the front of the cartridge touching the record surface. It's not ideal, best I could achieve, no listening refinement possible, as SRA is a squeak less than 90 degrees.
c. Listen. Much better, even though the shaft is bent, it still responds to groove modulations, it is amazing how good a damaged cantilever can perform IF the Azimuth and SRA are good.
Meanwhile, we found someone in NJ who can fix the Grace Cartridge, off it will go soon.