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5)
The “Fine
Tuning“
Everyone who has
to mount cartridges frequently understands the importance of precisely
adjusting an arm/cartridge combination to release it’s full potential.
Overhang, azimuth,
VTA, tracking force and, if featured, variable damping of the arm movement
are all important parameters.
The overhang
adjustment was described already, nevertheless let me add that a single
“perfect“ overhang setting does not exist. Should you own a lot of records
that are cut close to the inner groove you might consider using 63mm instead
of 66mm as your inner “zero point“ – many crescendo finales of symphonic
works could be tracked with reduced distortion this way.
On the other hand
exist a lot of “pop“-records with no modulation but leadout groove already
where the “inner“ zero point is located. One doesn’t even benefit from this
second distorsion minimum..
Correct overhang
adjustment results in tracing-error-related tracking distorsion of barely
more than 0.1%
Next, the azimuth should be
adjusted so that crosstalk is the same for both channels. This can be done
by using a mono record played back via an X-adaptor or through your preamp
switched to mono.
Reverse the
headshell clips on one channel only (switch red an green i.e.) and adjust
for the weakest signal coming from your speakers.
Once you’ve “hit
it on the nail“ a centrally recorded female voice should be precisely
located in space with no difference in the decay caracteristics between
channels.
The suspension
thread allows for “twisting“ the armwand-bearing assembly within reasonable
limits. The proper way to adjust azimuth is by turning the armwand setscrew
(e) loose enough to move the armwand and then turning the armwand
without altering overhang.
Starting with the
armwand parallel to the record surface, VTA adjustment can be carried out in
small steps (0.25mm, a quarter turn of the Allen key) until the best
separation between individual instrument in space, the least amount of
“grain“ audible and the best integration of fundamentals and upper harmonics
is achieved.
There is no
“perfect“ position, varying record thicknesses and a different cutting angle
used for most records made before 1965 neccesitate a new setting for every
other record. Stylus shapes are also more or less susceptible to changes in
the VTA – the “sharper“ the stylus, the more sensitive to changes..) The
more time you spend on adjusting the VTA the less you’ll get to actually
enjoy your records.
The tracking force
determines the tracking ability and also the position of the coils in the
magnetic generator. Follow the manufacturer’s recommendation and try
increasing or lowering the tracking force by increments of 0.1gr. Low
frequency tracking ability shouldn’t be lower than 70my. Soundwise more
relevant is the high frequency tracking ability. The appropriate tracks on
the Shure TT115 test record are helpful to get closer to the optimal
tracking force.
The damping is ,
as already mentioned, a function of the distance between the magnets, or,
more precisely, the flux density in the gap between the magnets.
It is to be
adjusted so that the lower registers will be reproduced with control and
heft without loosing the resolution of high frequency fine detail and “air“.
Overdamping this
arm is close to impossible (often the case with silicone fluid damped arms)
but rarely does the smallest gap result in the most satisfying sound.
The amount of
tightening of any of the arm’s screws has an influence on the energy
transmission and therefore dissipation and should be experimented with.
Generally
speaking, only screws a, e and f should be tightened
well. Screws b, c, and d require some experimentation.
Oh, and leave the
screw underneath the lower magnet alone. Once you’ve loosened it , the
magnets require realignment for which the arm needs to be send back to me. |
