VTA and SRA?

Czarivey and Effischer,

Your posts are incorrect. For a basic understanding read the link posted by Mofimadness above, which is *almost* correct.

VTA and SRA are both viewed from the side of the cartridge (along the axis of the cantilever, as Effischer put it) but that's where the similarity ends.

VTA = the angle formed between:
1) the horizontal surface of the record and
2) a line extended from the point of the stylus through the axis of vertical rotation of the cantilever (this would be the same as the line of the cantilever, except for the offset provided by the height of the stylus).

VTA's range from 15-25 degrees, with 20 degrees being the industry standard since the mid-1960s.

SRA = the angle formed between:
1) a vertical line through the lowest contact point of the stylus and
2) the line of the stylus's contact ridge or edge.

SRA's on elliptical, line contact, micro-ridge and cutting styli tend to be 1-2 degrees forward from vertical, but there is no industry standard. A conical stylus can be said to have no SRA. Its spherical contact surface results in a single contact point, so there's no contact ridge or edge to measure.

As can be seen, VTA and SRA are very different.

Read it again.

SRA = the angle formed between:
1) a vertical line through the lowest contact point of the stylus and
2) the line of the stylus's contact ridge or edge.

#1 never changes, but #2 can be changed in several ways.

The stylus's contact edge can be tilted forward or back by altering the height of the tonearm. It also changes as a side-effect of any alteration in downforce (VTF). Your own tonearm (listed as a Graham Phantom Supreme) has these adjustments.

You also change SRA (inadvertently) virtually every time you change LP's, since different LP's have different thicknesses.

Both would be changed.

Changing SRA without simultaneously changing VTA would require altering the angle between the stylus and cantilever... not recommended. ;-)

I imagine that people having difficulty understanding this also find it difficult to visualize other spatial relationships. They may be challenged by geometry, geography, map-reading and navigation, jigsaw puzzles, loading the dishwasher efficiently, assembling a machine from an exploded diagram, etc.

Quiz: most people can draw a rough map of Italy or Michigan from memory. How many can do the same for France or Maryland?

Whether SRA is worth measuring is another question altogether, one that's been discussed to death on many threads.

My own view is that while I can measure SRA on most styli I choose not to, since I've found it to be a waste of time. SRA differs from record to record, as Atmasphere just noted, so the best way to set it is by ear. Adjust as little or as often as one's ears and listening preferences require.

***
The vinyl zone and TAS definitions do contradict, and neither is correct. That's why I posted that the vinyl zone article was "almost" correct.

Re-read my SRA definition above.