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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. |