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Tr*nsSat*ter * 6_4 i«r t V Ov*f* r £ f W I o r 4 k if sk asv • The Wiring Diagram of the Amplifier Herein Oeecribed. By SIDNEY E. FINI'EUSTEIN, In New York Herald-Tribune. The honors in audio-frequency am plification seem to be divided more of lew evenly between the transformer end the resistance coupling methods. Bach system has Its stanch adherents, who are ever ready to fling masses of facts, figures and fancies Into each others' faces whenever a dlscuaalon of relative merits arises. The trans former supporters are Just as firm In tbety belief of the superiority of their Instruments as the resistance hench men are in their views on the advan tages of their devices. ' The writer has used both transform ers and resistances In the construc tion of a large number of seta and after studying the general results ob tained from them has come to the nentral conclusion that both systems are good, but that they are even bet ter If they are combined. In the Jour nalistic fashion, to the retalnment of of each. The advantage of the greater am plification per stage afforded by the transformer, combined with the flaw less reproduction but lower amplifica tion of the reslstancea makes the Ideal combination in the majority of seta A complete amplifier of this ad vantageous type can be made at home at surprisingly little trouble and ex pense, and once on hand It finds ap plication to receiving circuits of ail kinds. It may be built permanently Into a set or it can be left available as a separate unit for connection to experimental tuners. For the last purpose it Is especially convenient, as It saves the constructor of a new set the worry of providing suitable amplification to follow the detector tube. Pacta Required. An amplifier such as the one shown In the Illustration will require the following parts, which enn be pur chased at any radio store: Hard rub ber or composition baseboard 12 Inches long, 4* Inches wide and hi. Inch thick ; one heavy audio transformer not above 3*4 to 1 ratio, three stand ard tube sockets, two resistance cou pling units with two 100,000, one 500, 000 and one 250.000 ohm resistors ; one .0005 mfd. fixed condenser, eight bind ing posts and the usual busbar and mounting screws, definite A assembly procedure should be followed. First -the general location of the Instruments should be determined and all the necessary screw holes made In the panel before anything Is fastened down perma nently. The devices should be pushed closely together (there Is no danger from Interstage bowling, as there is only one transformer), so as to allow room on the right and left hand short edges for Input and output binding posts. The wiring will give no trouble. Aa a »tart the "P" and "B" posts of tbe amplifying transformer should be connected directly to tbe two bind ing poets on the extreme left, which are designated aa the "Input" ter minals The .0005 mfd fixed con denser is also placed across the wires and can be hidden comfortably out of way beneath the bottom of the baseboard. Of course small holes will have to be drilled In tbe com position to past the wires wherever necessary- . The Filament Posta Next the filament posts of the three sockets, which are all marked "F." are wired as shown In the -diagram, and« lead finally to the A battery * binding posta These should be the left hand two of the row of four along tbe long edge of tbe baseboard. With this much done tbe secondary of tbs transformer can now be wired to tbe grid and filament posts of tbe first tube socket Pro g re ss ing across, the condenser and resistor terminals ora wired In the manner Indicated In tbe accompanying hook-up. With- the rratotor units that were employed In this particular amplifier the protrud ing soldered tabs of the spring mount ings make the placement of tbe wires a abort and simple task. Tbe two poets on tbe extreme right are tbe output To one le run a wire from tbe P terminal of tbe last socket end to tbe other a wire from tbe B plus post, which is Immediately adjacent Tbe A plus and B minus ' peat*. If win be noted, are Joined to gether. All tbe wiring should be done with standard round or square tinned bus bar. Tbe wire need be Insulated with cambric tubing only In plares where two wires unavoidably pass each Tbe consacrions to the transformer, the sockets and tbs binding poets. which are all equipped with strong screw binding posts, need not be soldered, but those to the fixed con densers and the resistor mountings must be. The B battery should be of 135 volts, which Is the standard require ment for resistance amplifiers. With this voltage the 100.000 ohm resistors should be employed In the plate cir cuits of the first two tubes, while the 500, TO ohm leak goes between the first and second bulbs and the 250.000 ohm resistance between the second and third In the grid leak positions. This Is clearly shown In the wiring diagram. T wo Variocouplcrt Make Circuit Very Selective While a regenerative circuit may be readily obtained by inserting a variom eter in the plate circuit R 1* not 80 obtain tickler feed back with ordinary apparatus on the market nnlesd honeycomb colls are used. There are. of course, couplers with fixed tickler windings. With or dinary apparatus, however, the double coupler feed-back circuit Is easily ar ranged, the objections to single-circuit action are overcome, and there Is com plete tuning In every circuit and any desired degree of coupling between them. As commonly employed, the primary switches of one coupler are connected to the antenna and ground as osual. LU ±~ûi § S' 8 ■ Scheme That Qfvee Fine Control of Amount of Inductance. The secondary of this couplet, how ever, Is connected to the ends of the primary winding of the second cou pler, Tbe switch points of the second coupler go to grid and filament like the usual secondary connections. The secondary terminals of the second cou pler are connected to the pltfte cir cuit. The ware-length of the primary cir cuit Is adjusted by the switch points on the first coupler, aided by the con denser in the ground circuit variable condenser should hove a ca pacity of .0006 mfd. (23 plates). Tbs coupling between tbe primary and secondary is adjusted by rotating the rotor of tbe first vsrlocoupler. The secondary circuit Is tuned by the switch points on the second coupler and the coupling between the sec- ' ondary circuit and the plate etrcnlt tickler Is adjusted by the rotor of this coupler. The secondary of the second coupler acts as the plate tickled coll. Thla tive and give a little better than the average set's results.—Radio Newa CHECK SQUEALING Stop squealing lu the radio frequency set by: L Moving the coil closer to the end plates of the variable condenser. 2. Cutting down the number of turns on the coil primary. 8. Adjusting the grid bias with a potentiometer. 4. Inserting a critical resist ance, snefa as a rhéostat. In series with the grid of the radio frequency tube. Allow Space Between Units When Building When building e set a safe rule to follow Is to keep each piece of ap paratus at least two Inches or more away from other nnlta Tbe biggest mistakes often made In tbe construc tion of home-built receivers are try ing to cramp tbe Instruments in small quarters and tbe use of metal fixtures for the mounting. Cotla and other In ductances In tbe radio-frequency cir cuit should be placed as far to the rear and away from other pieces of apparatus as poaalbto. Winding of Coils To specs wires cm coll* the correct distance, start the cofl with thread aad wire, at tbe same time applying coo Mderably more tension to tbe wire than when no thread Is After tbe coll la wound and tbs sod of tbs wire fastened, the thread may be unwound. Have Antenna of Very Few Losses How to Construct Insulator That Will Be an Aid in Sharp Tuning. In this dayoand age of low loss re ceivers and high selectivity, writes s correspondent In Radio News, it Iq necessary to have an antenna of very few I oases, or the resistance of the antenna will be so high sa to make It Impossible to tune the set sharply How to do this? The antenna must be constructed of wire that will not corrode readily, enameled wire being the best However, the most Im portant thing Is to have the beet In sulation possible. The very beat In sulator for the antenna la air, but of course that la out of the question. Urn of the Plata Doubtless, someone will think that because this Insulator was designed for a transmitting antenna that it Will not be good for the average broadcasting antenna. It la only necessary to re move the aluminum plate at the end of the insulator and yon will have one of the very best insulators for a one-wire W A »am eso wuHcas CL*» Tuet COTTON 5 O*Kt 0 W SASA/riN ■. TIN SlATt Pisplata and Qiaos Toothbrush Holder Used for Insulator. antenna. The plate Is for use only when the insulator Is used on a cage antenna with a transmitter. The material that la necessary la as follows : Long type toothbrush holder with sorewcap at each end. This can be bought for about twenty cents. If the Insulator Is for transmitting antenna use a small aluminum plate. The other materials are odds and ends and can be found around the work shop. Using Melted Paraffin. Begin by moving the caps at the ends of the holder. Stuff small pieces of cotton In each end of the tube. Now It will be possible to pour In melted paraffin. Just enough should be poured In to seal the tube. This will prevent moisture from entering the tube and tbns destroying the Insulating power of the glass. Instead of paraffin, sealing wax, such as found on the top of dry cells, may be used to seal the ends of the Insulator. Now eyehooks of about tbe same design as shown In the sketch and threaded on the end, should be constructed. When the eyehook is at tached to the cap it will be found nec essary to place a big washer on the Inside of the cap and a smaller one on the ootalde of the cap. This will pre vent the ventilation holes on the cap from pulling out It Is a simple mat ter to place the alumlnnm plate at the end of the Insulator. When the plate Is used It should always be pot at the end of the Insulator which Is hooked to the antenna. When It la constructed, you will have a very fine Insulator, which takes very little time to build, has a remark able pulling strength and Is very cheap. S. L F. Condensers Aid Tuning of Wave Meter« The wave meter, whether It be plain or be made with all the finer Improvements,. Is one of the most handy pieces of apparatus any build er of receiving sets can have. Here tofore, tbe tuning of a wave meter bos been a rather difficult feat be cause a very slight change In capacity threw the circuit oat of resonance The Insertion of a straight-line fre quency condenser In tbaxbgre-meter circuit will greatly facilitate the find ing of the resonant point because a large change lo dial setting Is essen tial for a small change lo capacity, except at one end of tbe dial, but as the frequency variation is the same, tuning may be accomplished with the same ease. For wave-meter construction It Is essential that condensers with heavy plates, strong supporting members and accurate spacing be used. This necessities the use of sn instrument with concentric plate* because eccen tric plate condensers ore of a neces sity made with thin plates, which makes the capacity calibration sub ject to change without notice. How to Enlarge Holes When Building Receiver The best way to make boles in a panel large enough to take the Jacks or for tbe shafts of variable condens era, rheostats or other Instrumenta fal to first drill a large bole and then replace the drill with a flat file of rather fine groin. A fiat file will usually taper down to sufficient width to Just about sqoeese into tbe hole made by the drill and If it is turned in the brace slowly, usually in a re verse direction, the file will cut away the aide of tbe tarte, gradually enlarg ing It until It hi of sufficient size to accommodate the Jack. Do not try to work tbe drill feat or It may nap off tbe fila If It seems to stick and work itself Into a self-cut thread, reversa tbe direction end work at a slower rate. This method of enlarging boles will greatly assist In building tbs re cslvsr and at tbe tints will give Slants on Life By J A. WALDRON 77 A Superficial Conclusion nn HB servants of the Melfords were trained to a silence more subtnls slve than usual, though tike other servants they let their tongues wag below stairs. Those of them that bad to do with breakfast# especially might have passed with the dumb, for at breakfast Melford was Irascible If speech happened to Interrupt hla analyses of the financial pages, gven Mrs. Melford, who made It a point to come down to breakfast with Melford, was usually a silent partner at that function. This rooming, dressed With core, as always, she was so aBurtng that no man but Melford could have perused financial pages while he might have scanned her. She waa ten year* younger than her husband. "Do yon remember about the DellaT" she asked. ■ He was negotiating his coffee, end apparently dissatisfied with Its beat "The Dells? What about them!" "You promised me you would g®' to the affair tonight" "What affair?" "Why, they entertain, have engaged several notable artists to assist." "Dell has nothing elm to da bava Pm too busy." "But you promised me. And yon never go out with me nowadays" "I give yon full liberty to amuse yourself, don't IT And plenty of money and all that I have two or three deals on that take all my time. I'm about the first man downtown In the morning, and you find me at work Id the library when you come In at night I don't even go to my clubs." "But Isn't It your place* to go with roe once In a while—at least for ap And they I pearance' sake, even If you find no pleasure In my companyT" "Nonsense I I'm known aa a busy man. One of them days, when I've carried through the plana I'm work ing out, HI try to be what they call *a model husband.' Thon TU go with you as much aa you like." "Would you, really? I fear the habita you are forming will never be broken." "But you're having a good time, any way. You go to this and that con stantly. Yon have e box at the op "Thsrs Go«» a Man Hard Hit," Bald One. era, the theaters are open to yon, with dances and what not to fill In during the season. And yon play tennis and golf and go shout in the summer."' "Yes. 1 have to do these things for Mental relief—and to forget I tack your company." "Yet you must meet persons—as other women do—who are natural cavaliers—men who have nothing else to do. I like you to enjoy yourself'— be looked up to see a strange expres sion on her face—"and you must per mit me to go my way." "But people talk when they aee me About so much without you." "People talk about everything that doesn't concern them. Where's young Bloomer? Yon used to have him. to dinner quite often, and be noed to sqnlre you about. Why can't be still?" Mrs. Melford turned white and rosa. "I haven't seen him for weeka" she ventured. "Well, look him up. and please let me attend to my business." And Mel ford. who bad wasted valuable time, hurried out to bis motor and was away. A month afterward Melford entered a Wall street buffet earl y one after noon In an abstracted state. He rec ognised no one. Two brokers who saw him pass In the entry abandoned the ■object they had been discussing. "There goes s roan bard hit," said one. "You've noted that bis -pet stock. Orient Mining, slumped this morn ing?" "Almost to sera," said the other. "Have yon been caught In any of his misadventures?" "No. I hsd a bunch. I gueaa No other reason." -He'» rarely losing his grip. That'» whst a woman can do even when she's ont of the market." "Yea Women are to blame for a lot, even when they seem to be by stander«. Isn't It strange Melford didn't ee* his wife's game before It was too late?" "What do you mean?" "Why. she traveled with that young sport. Bloomer, a long time, afterward pretending- so the women say. that Mm tad broken with him for canse. Palled tbe word over Melford'« eyea" "And then eloped with the fellow I Ou yon beet It?" totpmsm.) 4 Fixing Responsibility "This is a dickens of a mess I** carped a hypercritical salesman. "This •now has been on the ground nearly a week. Why doesn't the mayor have it cleaned off?" "Well," replied Constable Sam T. Slackputter, the faithful guardian of the peace and dignity of Petunia, "the good Lord sent It and the mayor Hows the good Lord ort to dean It off."— Kansas City Star. • ** •*" Cuticura Soothes Itching Scalp. On retiring gently rub spots of dan druff and itching with Cuticura Oint ment. Next morning shampoo with Cuticura Soap and hot-water. Make them your everyday ,toilet preparations and have A clear akin and soft, white banda—AdveHJafcSëüt <■ Fuir Play Little Richard HVee with hla'grand father in Pasadena, bat he also has another grandfather who is an artist* a In saying his prayers the other night he surprised hla older slater by say log: "And pweas bwess my grandfathers —the one who paints pictures an* Ute one who doesn't"— Los Angeles Timet. Snowy linens are the pride of every housewife. Keep them In that condi tion by using Red Cross Ball Blue In your laundry. At all grocera—Adver tlsement * Getting Bach "The people in thq flat above us have a crying baby." "Get back at them," advised the agent "Ring."—Louisville Courier Journal. • ■ ; - . Don't Ask Him Dick—"Where did you go on yonr motor tour?" Dennis—"Oq«h ! I don't know. I was driving the carl" Children Cnr| r ♦ » I 1 I MOTHER:- Fletcher*» / Castoria is especially prepared V r / to relieve Infants in arms and y Children all ages of Constipa tion, Flatulency, Wind Colic 1 and Diarrhea; allaying Feverishness arising therefrom, and, by regulating the Stomach and Bowels, aids the as s i m ilation of Food; giving healthy and natural sleep. To avoid imitation», always look for the signature of Abaolntely Harmlc»» - No Opiate«. Physician» everywhere recommend it A Half-Stew A North side man tells this one: "I was downtown on a recent Sun day evening and, seeing an oyater sign on a restaurant window, I de cided a stew would be Just about what I wanted at that moment. "Going Inside, I said to the wait ress : 'A half-stew, please.' "When the steaming plate reached me I saw that the girl had certainly brought me a 'half-stew,' as six halves were floating about Instead of six whole oysters.'*—Indianapolis News, - Two of a Kind He— Ali, I wish I had some of the cakes my mother used to bake for roe ! She—And I wish I bad some of the dresses my father used to buy for me I —Sheffield Teleet-flnh.BH b* 6 ° For \ 0 AYE* / m •j# X h ll I PIRI Proved safe by millions and prescribed by physicians for Lumbago Colds Headache Pain Neuritis Neuralgia Toothache Rheumatism DOES NOT AFFECT THE HEART Accept only * 'Bayer" * package which contains proven dlrections. Haod r "Bayer" boxes of 18 tablets bottles of £4 sad 10O—DruggMa Ummtuctm tt H asBs cstl ee rifaetw «( at Nurse Advises Women Yakima, Wash. — "If the expectant mother wishes to keep well and strong I would advise bar to take Dr. Pierce's a Favorite Prescrip Hk tion. It not only K helps physically but w mentally also tor it ey keeps one feeling f so well that there .fit no need for worry. I found it so 'very beneficial in keeping me strong » and well and to quieting to the nerves that I always recommend it to my .patients;.apd- many of them have taken it'with splendid results. I do not think there is anything to equal it for t^y weak and ailing woman. It just seems to build up every organ in the body."— Mrs. J. OWeal, 410 N. 4th A vs. Al l dealers. Tablets and liquid. v x Green's \ tagest Flower fna at! potion ■ TarpM Liver ^ ■—' Relieves that feeling of having eaten unwlaely. 30c and 90c bottles. AT ALL DRUGGISTS Wanted, Old Fake Teeth W» per hi«h aa III (or full HU Dont manor It bream. Wa tor •■crown», brld««% and sold J»w»lrr. a Conditional Caller—Is Mrs. Blank at home? Green Girl—Ft you're for the bridga party, ahe Is; If you •ain't she ain't Corrupted freemen are the worst of slaves.—Garrick. ], Danger in Being Fat "A lean dog tors long race," is an old proverb, and a lean person for longev ity Is a corollary that life Insurance companies are more and more im pressing on the public. At a national convention of life Insurance men held recently in Chicago, the president, Mr. Albert M. Johnson, said that fat la killing off Americana so rapidly that special education Is needed. He con siders It more dangerous to be fat than to travel on a railway, an ocean liner or an airplane. What temerity It is. then, for a fat man to travel at olll—Youth's Companion. Forgive your enemy, especially If he has you down. The fool Is apt to either be! 1er* everything or nothing.