Origin Live MK3C arms dual pivot - Manual (Page 6)

Page6
and slacken it half a turn or so.
Just under the arm plate is the thin silver vta height adjuster
wheel – To raise the arm, turn the wheel clockwise (anti-
clockwise to lower it). The wheel has a dimple so that you can
see how far you turn it - each half revolution of the wheel is
equivalent to a 0.5mm change in height.
Clamping: For the sake of speed in vta setting, we
recommend that you leave the arm unclamped during the
comparisons. However it will sound FAR better clamped,
once you have arrived at the vta “sweet spot”. An Allen key
is provided for this purpose and the position of the clamping
grub screw is shown in the relevant diagram.
The wheel is capable of raising the arm around 30mm but not
more than 20mm is recommended for optimum performance.
Experiment with vta: It is important to experimentally set
the optimum arm height by listening to different vta settings.
If the arm base is too high, the sound is usually slightly on the
bright side and lacking body in the bass – too low and it veers
on the dull side. To enable precise and repeatable vta setting,
your Origin Live arm has an integral vta adjuster wheel. This
method of height adjustment is extremely accurate, with
obvious benefi ts in terms of speed of adjustment. This means
better listening comparisons between different vta settings.
Do not adjust Azimuth or any of the point settings
in the yoke
The adjuster points are set up very accurately in the factory for
correct azimuth. This is a very fi ne adjustment and one that
needs specialist knowledge of the arm. For this reason if any
of the grub screws are adjusted in the yoke other than by an
authorised dealer it will invalidate the warranty.
Counterweight position too near the
end of the stub? (optional read)
A common idea propogated in Hi Fi circles is that the
counterweight should be as close as possible to the yoke to
minimize inertia and reduce “see / saw” effects over record
warps. We believe this idea is based on certain observations
on particular arms that have then led to a totaly incorrect
diagnosis of the real causes of any performance changes
perceived. Although intuitively the theory of decreasing
the inertia of the counterweight seems very plausible, there
is another more proven explanation. The reason this is
helpfull to realise is that it gives peace of mind that when
the counterweight is positioned at the end of the stub on an
Origin Live arm, you are NOT losing performance.
The notion that counterweight position affects performance
has much more to do with vibration and lack of structural
rigidity than inertia effects - in other words on some arms it
pays to keep the counterweight close to the yoke as it decreases
resonance effects from counterweight “waggle”. On these arms
the counterweight causes an increasing vibrational whiplash
effect as it gets further from the pivot.
Origin Live have gone over and over this with their arms
and established conclusively that the counterweight position
simply does not affect performance very signifi cantly on a
properly designed arm. The idea that inertia is an enemy is
also based on pure ideology - the fact is that without inertia
the stylus could not read the record groove at all!
Some systems add weight at the headshell to INCREASE
inertia as it is proven to be benefi cial. 12 inch arms have much
higher inertia than 9 inch ones but nobody seems to bat an
eyelid!
The following calculations are given to try and give a sense of
proportion to a rather intuitive but incorrect notion.
Inertia differences are relatively insignifi cant. To get the weight
closer to the pivot, the counterweight has to be heavier and
this adds inertia - all in all a difference of 20mm or so is not a
big deal.
To illustrate this using laws of physics - the moment of inertia
is m x r squared where m is the mass and r is the distance to its
centre of rotation
Say that a 130gram counterweight is 45mm away from the
pivot - moment of inertia is 0.13 x 0.045 squared = 0.26 x10
to the minus 3
Equivalent downforce can be achieved with a 235g weight
at 25mm from pivot so - moment of inertia is 0.235 x 0.025
squared = 0.146 x 10 to the minus 3
This is a difference of 0.000114
Now compare this with the MUCH HIGHER increase
in moment of inertia cuased by a 16gram cartridge in
comparison to the average 8grams
16 gram cartidge inertia is 0.016 x 0.220 squared = 0.774 x 10
to the minus 3 (0.220 is pivot to cartridge distance in m)
8 gram cartidge is 0.008 x 0.220 squared = 0.387 x 10 to the
minus 3
This is a difference of 0.000387 - nearly 4 times higher than
the inertia saving of moving the counterweight in.
Another case of observations drawing the wrong conclusions is
the case of low slung counterweights. Low centre of gravity IS
important for unipivot arms but dual pivots and gimbal arms
do not “sway about” and it makes no difference in practice
to sling the weight low. As previously outlined, any benefi cial
observations are down to a heavier weight or different method
of attachment reducing resonance effects on certain arms but
not Origin Live arms. This is something we have tried and
tested repeatedly.