Gets Into Your System, How To Stop It
One of the most important issues
is interconnect dressing-the way interconnects are positioned
in your system. But grouping AC cords, analogue interconnects,
and digital interconnects right next to each other can degrade
your system's musical performance.
AC power cords, which carry
50Hz from the wall to your components, will induce a 50Hz
noise in any interconnect that happens to be nearby. Similarly,
a digital interconnect from a CD transport to a digital processor
will radiate high-frequency noise (in the megahertz range)
into analog interconnects, and even into AC cords. Although
you don't hear this contamination as audible noise, it overlays
the music with a grainy patina.
That's why the first rule of
system setup is to keep AC cords away from interconnects and
loudspeaker interconnects. If they must meet, AC cords and
signal conductors (interconnects and speaker interconnects)
should cross at right angles, not run parallel to each other.
Crossing interconnects at right angles minimizes the amount
of induced noise.
Next, avoid stacking two components
on one rack shelf. The components will be better isolated
from each other electrically, and get better ventilation,
when each is given its own shelf. Also pay attention to the
positioning of components within the rack. Don't put phono
preamplifiers near digital sources (CD players, transports,
digital processors), or close to a power amplifier. You can
also avoid running a digital interconnect next to analog interconnects
by thoughtful component positioning. Take special care with
the interconnects that run from your turntable to your preamplifier's
phono input; they carry extremely tiny signals that are easily
contaminated by radiated noise.
Anyone who's ever had to suffer through
poor TV reception knows exactly what interference looks like.
Stray signals and electromagnetic waves can sneak their way
into your audio and video gear, degrading both the picture
and the sound. It is virtually impossible to stop interference
at the source because it comes from everywhere: from the hundreds
of different radio transmitters that probably operate within
close range of your home, to the dimmer switches in your house,
to your telephone, your neighbor's electric razor, and even
the sun. Interference can occur at very low frequencies, at
very high frequencies, and everywhere in between. And most
of the interference that enters your A/V system comes in through
the interconnects, which often act just like antennas for
interference. That is, unless you choose interconnects designed
to combat interference in the first place.
Interference is a big problem for interconnects
that carry low-level signals like audio interconnects; for
composite video interconnects that carry signals from your
VCR, DVD player, and camcorder; and for video from antennas,
interconnect TV, and satellite receivers. Most audio interconnects
and video interconnects have shields, which are a metal covering
that surrounds the inner conductor of the interconnect.