Show 2 w ty T rf rj ri j i ll 11 01 n 11 1 s ca 1 I 1 9 1 k 4 f 11 1 f rz 1 p LZ 11 sa 7 fj cl r rj 0 aa 11 CX ct as C r 1 I f W bilhl r lih I 1 A 8 aa A simplified three tube circuit designed for ease of construction Construct fon operation and superb tonal quality H honeycomb oney comb coll coils used deed for tuning by BRAINARD FOOTE in radio world listeners who prefer moderate vol ame aino combined with almost perfect reproduction will ile he interested in the pimple entertainment receiver to be described the faithfulness of tta its tone output Is dependent upon the system of audio frequency which in thlu tiis met get Is a combination of a stage e of impedance coupled catlon cation and a stage of resistance coupled it III lilt abat loll 1011 lit in lie he use of the half limpet e power iribe li Is considered lit in the lie livit stage hinge since this tube requires about I 1 1 alts volts of n B battery the im fsr of resistance coupling calls for no additional plate voltage olt title nik c coupling la Is ad adopted pled for the first stage since tills provides probles super superior for delector nellon no lion and renter greater detector output p it I 1 moreover More oer with a n good impedance coll coil for tile first stage singe the quality 1 ll 11 4 good A honeyc ahne onit system of tuning Is in shown with a primary coll collmore collm mode tlde fly li v hie file expedient of eta eni cloying plo lii it fi dinall fixed condenser as ote lie coupling the of the li 19 not cult alt the out put of if volume MI unit Is not mit so ho great brent na as can IH be lined by li lie UM tire of mort inore guht tutus 4 and more audelo hut but iii 1111 tills this very ny ite nii count int KM its lie imie are better nud and its operation more pleasing lne will operate loud speaker A receiver nl elvor of ir tills this character will op orate 11 hood good houd speaker s elther either nt the file horn or foiw type to advantage lit in fill lip diagram ca G ly is taw coupling cond anser whereby the lie en ergy ni III by 1 r the lie wi wilemina letina Is deli tied to the he set 11 and cl forni form the cuned circuit aln alt of wf the set LI helni being ii 11 lOtu urn rii lione comb coll coil rind cl it amt i nin condenser 1 Is 14 handled bs t file lie al clift pill te 12 1 2 jilt and CJ IL 12 I L heink being another nn ollier oil if lit and botn mad alie two colls coll tire me mounted I 1 I 1 li y or two tuo oll if they should ile us ng fur far apart iii rt us lis so long lobit a Is to he fill and oil hie file longest waN is 5 form hie lie grid pi nl anti lenh in at 1 it MW I 1 inid cou er ei mid 2 loik leak TI 11 lind TJ 12 tire two ti JA type tie tubes wile reas I 1 ta 1 l Is it fill rulx of file lio 11 type takhing 14 ampere nt at 1 milts na I 1 1 l Is the lie coupling vo impedance for taw first stage e it mui may he be it n special impedance roll coil made for the purpose or with as good results the secondary winding of a large sized audio transformer this stipulation la Is made to Ins insure urethe the use of an impedance coll call having enough turns 0 of wire and core iron to pass all the audio frequencies 04 Is the coupling condenser for the first stage A condenser as small as an 2 mad will anwer answer fairly well here but better results are obtained both ns as to volume and range of musical tones it if tile the condenser Is made at 01 niad or yven even up to 05 mad A grid leak resistance rl ri of 1 or lull Is required to properly bias the grid of tube ta and nd t to prevent it from becoming choked with negative impulses instead of the impedance just juat described a coupling resistance Is adopted for the second stage since this to Is even better than an In impedance when it comes to passing all the musical frequencies power stage resistance ra should be approximately ohms 03 01 meg olim such can bo be purchased in the form of an ordinary grid leak and fill all the essential may be snapped into regular resistance clip holders these holders which como coin with the ra should be well wel made in order that tile the heating effect of the it if battery current that must puss pass through it may not alter after its re El stance mid and cause noises or distortion tion condenser ca Is lust just like ca tile the grid leak ra ra should have a resistance of about 34 4 lint bohnis to properly pio perly bins bills the last tube and prevent overloading or ch choking king tube 13 Is a A ampere poo power tube ared liec auge its greater p power ower wili will result in somewhat elint greater volume of output jilt tiina it very marked gain in tone quality since overloading Is eliminated A jack is provid i for tile the loud speaker connection the lie loud speaker LS 18 being indicated lit at this ills point now for or a few remarks about the battery rind and filament circuits rheo stilt III takes care of lighting the de and first stage tubes tl TI and ta while rheostat ra handles the power tube A snap switch 8 located tit nt the left nd of the panel serves to turn lite set on oil and off thus the rheostats tiny be maintained at the proper points permanently A 4 volt C battery 18 employed employs d its as indicated three 45 volt B units are arc required |