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If you are joining two pieces of audio
or musical equipment together, or two audio PCB’s, or wiring
controls to an audio circuit, you need a special screened audio
cable to keep the signal in and any unwanted interference out.
The most common interference is caused by the electrical field
radiated by the 230 Volt AC mains supply. Every mains cable,
inside your walls or leading from the socket on the wall to
anything you plug in will transmit a 50Hz hum that will be picked
up by any lead connected to sensitive audio circuits in
amplifiers.
Audio cables are simply a wire or wires that are protected by an
outer layer or shield of woven or twisted wire or foil that picks
up the unwanted hum before it reaches your audio signal, and
earths it harmlessly away.
As you will see if you browse your Maplin catalogue, there are
many different types of audio screened cable and although all of
them provide protection against hum, some are more suited to
particular jobs than others.
If you are wiring up simple audio amplifiers to small
loudspeakers, for an intercom or something similar, hi-fi quality
is probably not important. There are a number of inexpensive, thin
audio cables that are perfect for these applications, particularly
if the cable run is inside metal cased equipment or is only over
very short external runs. |
