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Show Alteration Tips on Jack Wiring Suggestions for Wiring to Suit Working Conditions of Radio Fans. By PETER DAVEY Tim majority e nets employing two stages of audio frequency nmpiinoa-tlon nmpiinoa-tlon have three Jiu-ks, one for plugging In each stage of nmplillcatlon and one for plugging In the detector unit only. It In tlioiiKht that the following suggestions sug-gestions for tho slight alteration of jai-k wiring will suit the pnrtk-iilar working conditions of many fans. The first suggestion concerns the last jack, which plugs In the second stage of audio. This Is usually a single circuit Jack, located In the plale circuit of the last tulip, as shown In Klg. 1. This Jack o B Is generally used for the loud speaker, nnd In the majority of sets the loud speaker Is plugged Into It for at least !K per cent of the time. So why not make the loud speaker a more or less permanent attachment and use the . Jack for the occasional plugging in of the phones? It often happens that music Is coming In quite well from a distant station on the loud speaker, hut fading occurs Just before the announcer's an-nouncer's voice comes In, and it Is necessary to plug In the phones to j find out who they nre. Pulling Plugs Is Annoying. To pull out one plug quickly and i Insert another Is, In the writer's ex perience, very annoying, especially If the cords happen to he twisted up. The arrangement shown in Fig. 2 Is a retlnement which saves this annoyance, an-noyance, and. the oiVy thing necessary Is to plug In the phones, the loud t-peawer rnereny being automatically cut out. In tills case (lie single circuit Jack Is replaced by a double circuit one. The loud speaker Is connected across the two center springs, so that, normally, nor-mally, it Is always in circuit. Now when the phones are plugged In ttie center springs, and consequently the loud speaker, are thrown out of circuit. cir-cuit. . . The fact of the loud speaker being always In circuit makes no difference differ-ence when using the phones in the first stage only, provided the second audio tube is switched olT, hut if it FijZ 8 yJj I is left switched on you will get a ! whistle so there you have a warning to tell you that you are wasting your A battery current ! The best method of connecting up the loud speaker is to have two biml-' biml-' Ing posts on a bakellte base, as shown In Klg. 2. These may be mounted i either Inside or outside t he cabinet. I There Is ft tip for broadcast listMi- 1 ers now here Is one for experhner i tn. What a nuisance it is to have . i I start ripplug down that set which is t working O. K. In order to use the parts for experimenting on another which . may or may not work successfully besides It Is liable to make one unpopular unpop-ular with the family. Keeps the Set Working. Rut If you Just cross over the connections con-nections of one Jack they may be enabled to enjoy two or three more F,3.5 radio afternoons while you are at the ollice with that old set before having to put up with the usual week or two of screams and whistles which accompany accom-pany the trying out of a new hook-up The Jack referred to Is the one for plugging in the detector only. For all the use vim ret out of It d,, it not seem that It might be dispensed with altogether, since it will not .operate' .op-erate' the loud speaker? Fig. 3 shows the conventional wiring for this Jack and Fig. 4 shows the suggested alteration. al-teration. It will be noted that In (he latter ' case those wires which were on the outer springs are now on the inner, and vice versa. : Now, if tlie plug Is Inserted In the 1 Jack and two leads connected with 1 It we have a connection to the am-plitler am-plitler unit, to which any detector unit can be connected for experimental pur- ' ' ' ! (fFp) -ri ci'io poses, and this wfthout disturbing tho existing set in any way whatever. It also lias the advantage that the relative merits of two or more hookups hook-ups may be tested on the same stations sta-tions and under exactly the same conditions. con-ditions. New York Sun. |