Links (analog style) and downloads
Above illustration: Effective Length
Def: The straight line distance from the tonearm pivot to the stylus.
Above illustration: SRA and VTA
Def: VTA, Vertical Tracking Angle describes the angle between the record surface and the cantilever.
Def: SRA, Stylus Rake Angle, or Scanning Rake Angle describes the angle between centerline of the stylus and a plane that is perpendicular to the Record Surface.
Both of these elements are part and parcel of the same adjustment. If you say you are adjusting VTA, you are also altering the SRA. The distinction is offered to explain the need for the stylus and it's cantilever to duplicate the vertical swinging motion of the original cutter head used to cut the master. Critical for the fine tuning of elliptical and fine-line stylii, the closer the SRA can be adjusted to match that of the original cutter head, the more information the stylus will retrieve from the groove. If we could shrink ourselves small enough to climb into the groove and see the relationship between stylus and groove, we would begin thinking in terms of adjusting SRA because SRA describes the angle of the stylus. VTA describes the angle of the cantilever.
Adjusting VTA on a Thorens TD160
All images copyright © Steve Clarke
3d geometry created in Rhino and then rendered with Moray-POVray.