Origin Live Aurora MKI - Manual (Page 12)

12
S E T T R A C K I N G F O R C E & S I D E F O R C E B I A S
TRACKING FORCE
Set the tracking force to the manufacturer’s recommendations using a stylus force gauge (stylus balance).
On all modified arms, Silver, Encounter Illustrious and Conqueror set the tracking force by sliding the
counterweight along the rear stub until the required tracking force is attained, then clamp up the grub screw in
the side. When adjusting the counterweight, set it so that the Allen bolt is at the side of the arm (not at the top)
see figure “Rear end view of counterweight” . You will need a stylus force gauge to measure the force
underneath the cartridge tip.
HINT - In conducting this operation it helps to just lightly “nip” the allen bolt in the side of the counterweight
onto the stub – this way the counterweight has a little friction to hold it in position as you slide it backwards
and forwards. Once you have set the tracking force correctly you can firmly tighten the allen bolt in the
counterweight to secure it tightly to the rear stub then check that the tracking force is still correct after
tightening.
On the OL1 tonearm which has not been modified (i.e it has a plastic rear stub with spiral groove) – You
should turn the counterweight till the arm balances level – once this is accomplished you can then set the
tracking force by turning the counterweight – half a turn = 1 gram.
R E A R E N D V I E W O F C O U N T E R W E I G H T A N D A R M M O U N T I N G
GRUB SCREW POSITION
IS HORIZONTAL
PLINTH OR ARMBOARD
BALL BEARING
ALLEN GRUB SCREW
ALUMINIUM SLEEVE VTA ADJUSTER
THREADED ARM BASE
ARM MOUNTING PLATE
(ARMBOARD)
Use of Stylus force guage
Most stylus force gauges work on the same principle as a set of scales or balances. For example with the
Ortofon Stylus Force Gauge, first place the stylus on the inscribed or graduated portion of the scales. Then try
the stylus at different points until you find the point where the beam “balances” freely in a roughly level
position. You then read the force that is being exerted –( 1gram = 10 mN if the scale is in mN). From this
number you can assess whether you need to increase the tracking force or vica-versa. Move the tonearm
counterweight accordingly and re-measure the tracking force. Repeat this procedure until the correct tracking
force is obtained. The Shure stylus force gauge works slightly differently so follow the instructions that come
with the gauge.
SIDE BIAS FORCE
Once the tracking force has been set you can set the sliding control for tracking bias - This should be set to a
value of approximately 1 or less due to the fact that the bias adjustments on Rega arms and similar arms tend to
under-read the true value of side force produced. . The settings you read on the Rega, OL1 or Silver arms are
not always dead accurate so it may be worthwhile to fine tune the setting using the following method. Find a
test record or a record with approx 10mm of blank vinyl between the end of the lead out groove and the record
label. Place the stylus needle on the blank uncut vinyl and see whether the needle skates inwards towards the
centre of the record or outwards. You are aiming to achieve a situation where the needle drifts slowly towards
the centre of the record so adjust the side bias until this state is reached.
As the stylus tracks across a record it experiences forces that tend to push it towards the centre of the record. To
counteract this force the arm is best set up with an approximately equal and opposite force called the “side
bias”