Kuzma 4POINT 81126 - Manual (Page 14)

14
APPENDIX 1
Tangential Cartridge geometry adjustment
Once the cartridge has been mounted, it is necessary to ensure that the cartridge is tangential
to the record grooves in order to minimize tracking distortion during playing. As the cartridge
moves in an arc across the record, tracking distortion occurs and is minimized by the tonearm
geometry and the angle of the cartridge in the headshell.
With optimum tonearm geometry, very low distortion levels (below 1 %) can be obtained
across the entire playing surface. Cartridges have zero distortion at two points on a record
and these points are used when aligning the cartridge. In practice these points lie at 66 mm
and 121 mm from the record centre (see protractor). Other protractors make use of different
zero points due to the use of different parameters in calculation. In this case 60 mm has been
chosen as the inner groove and 146 mm as the outer groove which still has optimum tracking
distortion.
1. Ensure bias is on minimum or switch off.
2. Place protractor over spindle on platter.
Note:
If you have difficulty seeing the cantilever it may help to raise the arm a few mm, taking care
that the protractor does not rotate. This also prevents tilting of the cantilever due to the effect
of bias force. It may also be helpful to fix the platter by inserting a wedge between platter and
plinth and by inserting a sheet of white paper to give a clear background while observing the
cartridge. Use a strong light.
3. Alignment at zero point 66 mm (A):
Place tip of stylus on point A (ie. zero point 66 mm). With a strong light observe cartridge
from front. The cantilever and the line on protractor should be in perfect alignment.
If the cantilever is not, then the body of the cartridge will have to be rotated slightly.
Do not adjust cartridge by observing body of cartridge only. (Fig.14)
Fig. 14 Alignment at A