Show edited by U douglal editor of by 0 GE E HAMANN the following experiments while involving no new principles or theories may nevertheless prove interesting to the ha broadcast listener particularly when a little variety in the evening program Is desired all the apparatus required Is a two stage audio amplifier a single head phone and a loud speaker a single phone with a horn attached to it will do for a loud speaker for experiment nu 1 connect the head phone to the input terminals of the amplifier 1 e across the primary of the first audio transformer light the tubes and plug in the loud speaker on the second stage in the usual manner see bee sketch hold tile lie head phone with hands cupped around it to form ft a mouthpiece and talk into it in a low voice the voice will be reproduced in the loud speaker with greatly increased volume the reader can easily cosily think of a dozen different ways of arousing amusing himself with this at his next party set awa 4 how to co connect knect the apparatus for the experiments described in this article up tho the loud speaker in tho the parlor where the guests are assembled and run a long telephone one cord to the radio set in HOMO BOIDO other part of the house tune in a selection front from sorte HOMO local broadcast station and plug in the loud speaker at the end of the selection sel atlon switch off it the detector circuit and do your own announcing giving tile tho station ca as england australia or honolulu the buky Is the limit the effect on the and lence wilt will bo be startling to nay the least As AB a precautionary measure however first make sure that there are no hard boiled hams among the guests otherwise you may start a riot getting buck back again to tile the actual application pt leation it 1 the lie audio amplifier Is a separate unit the connections are very simple as seen by the accompanying sketch if however the amplifier la Is in the same cabinet with the receiver it will be necessary to connect two wires to the primary of the first amplifying transformer and bring them out to tile ahne me which Is to be used as a transmitter A telephone jack and plug will simplify cutting the transmitter in and out of tile the circuit use n R double pole open circuit jack this can he be left permanently connected to tile tho set as it wI will lInot not affect its operation in any way except when the head phone Is plugged in if a broadcast program la Is being re calved and it Is desired to interject a little homemade home madO announcing first cut off on the detector circuit by turning the detector rheostat to the off position and then plug in the licad head phone transmitter another similar experiment which produces rather unexpected results consists of connecting the loud speaker to the input side ot of the amplifier and listening with a pair of head bead phones plugged into the second stage the loud speaker will net act as a microphone and pick up any sounds produced near it these hlll be amplified and reproduced in the head phones with tremendous volume it if the loud speaker Is located in some other part of the house it will pick up voices from the same room and reproduce them in the head phones as clearly as though the listener were in the room where the person was speaking this last experiment may prove highly entertaining if 1 conducted on a wednesday evening when sisters beau Is calling news |