Is VTA and SRA the same thing?


Hi Audiogoners.
I understand ther refer to Vertical Tracking Angle and Stylus Raking Angle.
What I would like to know is are they the same thing? I mean, every time we change the VTA, let say 1degree, then the SRA will change the same 1 degree?
Thanks,
Calvin
dangcaonguyen
dangcaonguyen
So the VTA cannot be adjusted by the end user?
The VTA can be adjusted by raising or lowering the pickup arm, but the optimum VTA is determined by the phono cartridge manufacturer and - to an extent - the VTA of the actual cutting stylus.
Strictly speaking the VTA is the angle made by the stylus tip to the cantilever attachment to the cartridge. It is a bit different than the angle of the cantilever itself.   

The SRA is the angle that the stylus rake makes with the recording.  It can be different than the angle of the stylus (if by that is meant the angle of a line bisecting the stylus front to back).  The rake is the sharpest parts on the sides of the stylus forming ellipse or line contact with the record groove, left and right.

Perfect alignment would have the rake be at the same angle as that of the cutting stylus when the record masters were cut. Somewhere around the 92 degrees mentioned.  It can be different as cutting angles were not always at 92 degrees.  Hence for the happily obsessive, different SRAs for different recordings--and on the fly.

Of course the SRA and VTA cannot be aligned independently.

Conical styli have no rake (and no SRA)  and the only thing then to align is the VTA at around 20 degrees.
Modern cartridges are very well made. You set the VTF to the manufacturer's recommendation then raise or lower the tonearm until the arm is perfectly parallel to the record. This will give you both the correct VTA and SRA. Trying to set SRA by viewing the stylus is a ......difficult way to proceed even if you have loops and a micro protractor.  
melm
Strictly speaking the VTA is the angle made by the stylus tip to the cantilever attachment to the cartridge. It is a bit different than the angle of the cantilever itself.
That's a fine distinction but it's absolutely correct.
Conical styli have no rake (and no SRA) and the only thing then to align is the VTA at around 20 degrees.
Actually, conical styli are almost immune to VTA alignment, so anywhere even close to 20 degrees will be more than fine. (The spec becomes increasingly critical as the stylus shape narrows to elliptical to hyperelliptical  to microline ...) That's why some phono cartridges with spherical styli remain so popular - they're easy to set up.

But overhang is as critical with spherical styli as any other stylus shape.