LOUDSPEAKER CORDS

Radio Record, Volume I, Issue 31, 17 February 1928, Page 3

LOUDSPEAKER CORDS

SOURCES OF TROUBLE. The loudspeaker cord is such an insignificant part of the wireless set that few ever give it any consideration. Yet it is sometimes the cause of much crackling, which many imagine to be static. Speaker cords are made of very fine copper wire, twisted with a piece of cotton thread. The whole assembly is covered by a woven cotton or silk braid. Sometimes one of these minute wires will become broken, and any movement of the cords will cause a scratching sound in the speaker or *phones. Such a noise will be located when the ’phones are shaken. During damp and rainy weather, or around the sea shores, the fibre covering the conductors may become moist and leaky and cause noises in the speaker. This trouble is harder to find, for if we check the parts of the set with the speaker connected,

as the noise will still be prevalent, it it likely to be assumed that it is caused by static. As a protection against such trouble, a speaker cord with rubber insulation should be used. Grasping a ’phone cord and not the ’phone tip when withdrawing it from a plug will often cause scoring of the delicate wire, with consequent breakage and noises in the set. By -n en --

connecting a small lamp m series with the ‘phones or loudspeaker, and a small dry cell, flickering of the light will occur when the cords are moved around in the case of a broken wire. If you are troubled with hand capacity effects in the *phone or loudspeaker cords, a small fixed conden‘ser connected between A positive anil a separate earth will either eliminate or minimise the trouble.