12
Protractor – position from top
Move the cartridge along the headshell to such a distance, that the tip of the diamond (needle)
is on the line on the protractor, which goes from centre of record towards edge of record.
This is the line where the tip of the diamond will be 'tangential' to all grooves on an LP.
Using the cueing device, just lift the needle above the protractor for an mm or so. Move the
tube along to see if the needle is travelling along this line. If it is travelling parallel to the
line but in front or at the back, then reposition the cartridge. But if it travels at an angle to this
line, (e.g. if tip is at line 66mm but not at 121mm) then rotation of the tonearm must be
repeated. The protractor was not precisely aligned against the base, or the cutout for position
of the armbase was not precise. Experimenting with small rotations of the tonearm will solve
the problem. The tip of the diamond must travel parallel to the centre line, even if it is in
front or behind. Now simply position the cartridge backwards or forwards. When you are
sure, check by actually lowering the tip onto the protractor. The cantilever will deflect due to
the tracking force.
When this is complete the needle should travel along the line. You must achieve a tangential
position on the grooves. Rotate the whole cartridge without moving it along the headshell, so
that cantilever is tangential to the parallel lines. Just chose one and then align the cantilever
to be parallel, by twisting the cartridge body in the headshell.
When this has been done, check again if the needle travels along the line from the centre of
the spindle. Check again, if cantilever is in a tangential line. Fix the cartridge screws one at
a time, gradually, being sure not to move the cartridge.
After the cartridge is firmly secured check geometry again.
Note: Do not use the damping facility while levelling the tone arm! Lift out paddle from
oil.
