Show by LEE in radio world tro tubes instead of one in the dinst step steil of a two stage singe coupled alit dudlo lo frequency improve quality greatly anything within economic mid scientific reason that hint improves quality of the received signal should appeal to radio fans sets seta that operate a spen speaker her even the faithfully reproducing cone type without audible distortion constitute tile the best possible encouragement of greater growth tin and probably 85 to 00 per cent of the tube sets in use us today produce distortion that Is discernible ly by tile the ear trained to the best radio reception fon why should your sot set bo be in tills class I tire ro much cheaper now than ever before the additional cost of one tube co counting tintIng its ita tube tuba life no na well as battery current consumption ts Is so BO low flint anybody who can nf af ford a four tubo set can afford a tive tube set net therefore tills this circuit Is presented it af anca ca ive five tubes the first la Is it a tuned radio frequency amplifier tile the second la Is tho the regen rated prated detector the third la Is thil regular first stage binge of coupled couple audio frequency tho the lust last two tire connected tubes to handle tile heavy load of tho the stage of audio distortion may inny nilso from ninny many causes including oven even UP HV feedback or stray coupling between stages lint hut tile tie ajillo side eldo of the circuit Is most moat often responsible As tubes tire made today unless it a power tube Is employed which ancans much greater expense or push pull resorted to or the pari parallel lliel levies device presented herewith tile lie load on tho the last transformer audio I 1 F A A J V at M Z wiring diagram tube will be too grent great many who have listened to their set on earp horos a plugged into the detector circuit till bixl even listened on tho the first audio stage have remarked upon the decline in quality when comparison wits was made with the alual audio output what the circuit does doea tile the circuit itself aside from tile the dudlo fen feature ture Is IB one that gives splendid service there are three controls two of which may be fogged the other control Is the ti tickler elder which affects effects volume and the setting Is 14 not to gable for selectivity nna distance reception it Is liard hard to produce a n better circuit the Is IR only a little more sensitive and scarcely tt a bit more selective L As a test of selectivity the set inny be used near a powerful brond broad tasting station and will tune it out I 1 if t only aerial Is used tile the ground connection Is entirely omitted in that case the set Is to he be neutralized so far us its possible tile the success of complete neutralization Is doubtful since somo some signals way may be heard without aerial ground or loop being used hence tho the heterodyned note might escape hut in fit fact tho the neutralization Is practical in that no radiation need be expected that will annoy neighbors with the set oscilla oscillating tin mn experiment wils was made with a receiver celver te hooked up tit to an aerial six feet away front the nn all tenna lenna used for the oscillating set squeals could be heard from the oscillating cil receiver by the person tuning it but the family living on oil tile the floor below using the other receiver heard beard no squeal and that Is the ob je luct cit of it in the present cise case neutralization la in effected by COD necking a neutralizing condenser from the lie grid of the lie UP III tubo tube to it tup tap on file secondary of tile 3 circuit coupler if commercial colls coils tire are to be used in tills this set any 3 tuning colt coll may bo be employed the usual type has a nn n inductance requiring a m mad fd variable condenser iloth colls coils should khouli bo be tuned by condensers of the a samo capacity for logging simplicity ali aa commercial 3 circuit couplers do not usually have A top tap for the neu connection tills this tap may bo be ande by the constructor slightly balse the eighth turn from the grid end of the secondary scrape off a little insulation nad solder a flexible lend lead thereto tile the other end of this lend lead goes to one tilde side of the neutralizing condenser which of course Is a variable instrument making the colls coils if the colls coils are to be wade ninde at home LI 11 would consist of ton ten turns of no 22 nn single cotton covered waro on n 3 inch diameter tubing and 12 would be 45 turns of the same kind of wire wound tit in tile the some direction the coupling coll plIng may bo be close preferably should 1101 ild be ns no tile added apparent resistance rosi si makes for better stability tile usual 34 l inch separation may be used timed between primary find nd secondary if the constructors preference runs that way the 3 circuit tuner would be made of tho same kind of wire on the same diameter tubing fill all windings in tho the sumo smile direction 13 would be ten turns if the coupling Is close between 13 and IA 14 and between tickler all and secondary then about two extra turns should ile be put on the secondary making 47 17 turns its as against the 45 for the secondary the reason Is that there la Is an absorption effect which deprives tho the secondary of some of its inductive value the extremely y loose coupling that flint would be required if the darys value in was to bo be what the inductance duc tance tables call for with a given number of turns Is hard to realize in the tickler LB 15 consists of 1 34 turns of no 20 26 wire on oil a 2 inch tubing 2 inches high aach of the Is in 4 inches high the two colls coils when mounted may be at right tingles angles which la Is more easily accomplished by having the mounted on tile baseboard its axis parallel thereto the condensers for the colls coils ns no described tire are mad straight line frequency condensers conden sera will make tuning easier on the low waves vales ns as will straight line wavelength wave length condensers these tire lire distinguished from the straight line capacity condensers by tile tho fact tile the preferred ones have shaped plates list of parts needed one radio frequency transformer LI 12 one a 3 coupler 13 11 14 LB two IB 15 olim rheostats rl RI one ohm gohm G rheostat ono double circuit jack JI 71 ono single circuit jack 32 two to rush push pull battery switches sl sa one mad fixed grid condenser t one nr lable grid leak eak 11 3 two tudd variable condensers cl ca 0 ore r e neutralizing condenser N one volt 0 battery or two of them two 45 volt 11 II batteries ono one storage A battery 0 6 volts to amp hr one 7 by 2 1 inch panel ono one 7 by 23 inch baseboard three 4 inch dials sixty five e feet of aerial ground lightning arrester earphones speaker connecting wire screws no 14 insulated lendin leadin lend lead in wire |