Loudspeaker Breakdown.

Radio Record, Volume I, Issue 47, 8 June 1928, Page 12

Loudspeaker Breakdown.

Beet KROWN ot lonisucaker wiilings, when counected , directly in the plate circuit of the fast valve, is due to the surges of current, wltich momentarily ass through them when the receiver is switched off _A super powet-valve with a reasonably high plate voltage will pass a current of, say, 10 to 15 milliamperes, and ' this heavy current wil! saturate ‘the }ole-picves of the loudspeaker, with’ the result that slight variations in cutrent thioagh’ the windings will not pro-: duce sympathetic variation in the magnetism of the’ pole pieces, and -the diaphrazm or reed will not resnond to, all the variations in carrent. Cniess the diaphraem laitnfrtly follows these variations Mistortisat is inevitable. ‘Fhe use of a choke filler overcomes these’ troubles, and also ‘minimises any ten . denev te low frequenev oscillation.