- What sort of cable do I
need?
- Can I make the cable as
long as I like?
- What else do I need?
- How do I join up the ends?
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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. |
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