AnalogMagik Tutorial No 4:
How to set Vertical Tracking Angle (VTA)
Vertical Tracking Angle
Vertical Tracking Angle refers to the angle of the tonearm when viewed from the side. This, in turn, determines the Stylus Raking Angle (SRA), it is the angle in which the stylus is raking the record grooves at. An excellent place to start the VTA Angle is to visually observe the stylus raking angle.
The generally accepted theory is that the optimal SRA Angle is the angle at which the LPs are cut at, in most cases, this will be 92 degree, but a certain amount of variability is possible. Without a microscope, it is often difficult to observe the SRA, so an approximate starting point will be to adjust the VTA to about 15 °.
The Acoustical System SMARTstylus is an excellent tool which will allow you to visually gauge an initial Stylus Raking Angle. The Uni-Scope Magnifier will also allow you to visually magnify the stylus to magnify the stylus 200x on your computer screen.
The theoretical optimal angle of 92° is based on the assumption that this angle will produce the lowest intermodulation distortion (IMD%). Visual methods provide a good starting point, but as soon as the platter start spinning, the dragging force created by the stylus raking on the LP will produce a downward force which will cause the raking angle to change.
Only an actual measurement performed while the recording is spinning will produce the most accurate results. This is unachievable using visual methods.
The AnalogMagik software has a VTA function which allows you to determine the actual intermodulation distortion number and it will be displayed on the laptop screen. Simply fine tune adjust the VTA angle until you reach a level which produces the lowest intermodulation distortion percentage (IMD%).
While performing this measurement, you may discover a small nominal difference between the left and right channel. All cartridges will experience a small difference between channels, this is limited by cartridge quality, and it is not a programming error.
Again, we emphasise that an optimal reading is also affected by Azimuth, Anti-skating, as well as Vertical Tracking Force (VTF), you may need to go back and forth between parameters to achieve an optimal setting across all parameters.