Show by BREWSTER LEE in radio world one of the favorite combinations of audio frequency with fans who are strong for volume and quality embodies one stage of transformer coupling and two stages of re el si stance coupling the advantage of this type of audio amplification Is that there Is an all voltage step up in the first stage and when the signal Is further amplified this la is accompanied compa cOmPan nied led without sacrifice of quality the volume is in all that anyone could ask especially when a type of loudspeaker Is used that reveals the slightest trace of distortion this audio hookup will function without offend ing the speakers sensibilities used with tho popular 8 tuner this combination of a dudlo u dio ainsil fica tion la Is eminently on satisfactory fis factory the si al stances used lathe in itle audio stages are designated in ohms in the wiring diagram ra and are grid leaks and you may have the I 1 leak IN around the house bouse also the 6 5 grid leak ita and are 1 colic coils for the sel sat the varlo coupler may ajay he be a standard 8 circuit coupler tuned by cl CI a mad variable condenser normally 23 plates use doe vernier for the condenser dial A coupler may be constructed at home by winding iala on a aw 8 diameter tubing 41 4 high using no 20 double slik silk covered wire the primary ll LI consists of 10 turns right next to lt it as close as an possible wind 48 43 turns for the secondary the tickler 18 may be spi der web loranz or any ajay other form of winding consisting of 28 turns of no 20 26 single bilk covered wire on a 21 2 diameter form 2 high lorenz basket weave winding may be used throughout with the same mean diameters preserved with larger wire used only tor for ll LI and 12 no IS 18 double cotton covered wire Is good for this purpose the tickler should have finer wire as previously described hut but when the larger wire Is used for lila add four more turns than those specified I 1 used a solenoid the are arc trl tri tuner other parts paris in set the grid condenser ca Is of the fixed type nal nfl capacity ill 4 I 1 40 Q is ad is a I 1 imo 00 to three circuit with three stages audio frequency amplification Is a variable grid leak connected from the grid post of the detector tube socket to the filament plus post of that socket which means in this case to A battery positive 03 Is a fixed condenser mad used as a jl ji Is a double circuit jack ja Is a single circuit jack the wiring diagram may be used tor for employing this system of audio amplification on any set either the detector tube or crystal RT t Is a 15 ohm rheostat for or tubes or 20 ohms tor for the godlop tube if me eladion li in used the grid rid return of toll tub Wt the negative and the detector tube rheostat be placed la in the negative lead instead of the positive lve this holds true also for the and tubes the audio tubes should be or naoia although or tubes tilbee as well as a and may be used throughout with somewhat less volume i rheostat to use U in the audio part of the circuit 04 rord fixed condenser la Is optional the coupling condensers conden serc are mad as ae designated one rheostat 0 6 oh in designated ra controls all three audio tubes thus when one desires to listen on earphones ear phones only the three audio tubes may be turned off by means of the rheostat ra |