Kuzma STOGI REF 90630 - Manual (Page 16)

16
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. Note: Ensure bias is on minimum or switch off.
2. Note: Place protractor over spindle on platter.
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 66mm (A):
Place tip of stylus on point A (ie. zero point 66mm). 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