Show by 0 douglas DUR editor of radio looks merchandising I 1 na set alaa 10 iyo i yo 1 diagram showing direction directions which must be 0 followed for construction of the th two stag stage crystal amplifier by PETER MOMBELLO tube amplification with if its persist ing inc noises 1 has ha been ho the only thine thing to prevent a radio set ft from com comparing larIng very fa favorably faor orbly ably with a phonograph for clear music alo also because of thebe colie moises ninny many radio fani fans who A ito arc are POW rati fled with the locals have gone one back to the crystal polls ti to enjoy clear natu ml and faithful reproduction ahw 1 I heir properties of the tile crystal account for its it existence in thia tills age of multi lube sell acl if it the crystal can con he be used ni as a detector iby athy cannot it be lined used as a an n amplifier if fill terin mil ii Is appropriate As it matter of fact it can he ile timed in the latter any ny and tir the rent rest of fills article will be demoted to the tile construe tion of a two stage amp amplifier lIfler crystals die the following partis will be needed two audio frequency transformers one of 10 to I 1 ratio and another of 0 to I 1 ratio two to perfectly insulated crystal detector unit units two acry genii ean the uie crystals two tuo mien fixed condensers auld capacity one B battery ili volts six binding poet ts and one badlon panel 7 by 5 all these part parts are to be very efficient and consil dering the lie fact that they cun coin be used over and over again it it is worth while to pend a little more and find get food good ones the first time mint must follow fallow direction directions the diagram given with this article must be followed alry carefully of pedal special importance li Is the connection after the first amplifying crystal cry etal the wire that comes from the secondary of lie the first transformer and goes through the crystal Is to be connected to the secondary econ dary of the second transformer if this connection should go to the tile primary the amp amplifier lifler mould not work and the sensitivity of the first crystal would be ruined by the bat tery no baseboard Is to be used the ine transformers should be mounted at right angles to each other on the in side of the panel the first crystal should be placed aboto the first trans fonner and the second crystal above the second transformer on the front of the panel the connections to both of them should be reer reversed sed to give the best volume the input posts should be on the left and the battery posts and output poets posts should be on be the right in wiring uso pure soft drawn dravin copper wire or fold gold plated wire under no circumstances should you use the tinned bus bar wire as its ito surface con where trouble comes in altering your S C set the trouble in altering the single circuit set in getting the tube to oscillate it at the he high waves and also hi in the loss of volume and distance reception when dry cell tubes are used in trying to overcome these two things the ultra audion circuit has been sug sot tested at different times but this circuit in its standard form also has hits shortcomings it little better if U any than the tuned plate circuit the re receiver celver described herein Is 3 an in improved ultra audlia circuit that nils fills 19 secondary circuit connected in ultra audion manner the bill both in ease ot of oscillation end and in distance of reception IOEL A lance glance at the circuit will show to the fan fin that it Is a two circuit tuner with the secondary circuit connected in the ultra auction ru manner ariner the primary and secondary madary se colls calls of the set are re the stator and rotor respectively ively of an ordinary varlo coupler the secondary tuang condenser may be the one formerly used in the aerial circuit of the old single circuit tuner the other variable condenser has a capacity ct f mad this condenser to Is included for the purpose of eradicating the fault of the old standard cier audion circuit E a fc uncontrollable oscillations the two axed condensers shown in the secondary dury circuit must be good well condensers that will not blow when lien the 13 lottery Itil tery Is applied ap pIled other wise the tube used in the set will be burned out the grid condenser and jest nt are re standard darl it Is suggested tait ahe he constructor experiment with 11 leak in tate siet after offer be has his I 1 sni arc 4 fie ilie butac tn varicia Is 1 very low make all con nations elections direct in straight line lines and absolutely very amien lien soldering the connections to the lie crystal tt nr units make sure that you remove lie lit ui us they mill be nimrud by fly the heat beat or eid by the tie soldering flux lor for the tile sake of tone quality cioe fluid codih hav ins ing a narn and connect liese 1 I acce on tin hie file of tie ne tin ihrman in the tile diagram bine differt lit ary cry gristly 1 in their it would ie te worth orth lilt ile in to experiment with tile cul nelty of ibe 0 ao 10 o ld although a II 11 bi of 22 oleat lt in 1 to fit force the ho oll ol toils aills through the flip amplifying r lie tile unit should he h built alth flit the flip of care as eury eiery hit flit of energy in lit to too be ile I 1 reserved if lie amplification IN 14 to be successful operating amplifier in operating this fills r corin pet the ilia phone terminals ermI nals of the not met to the primary of the ilia M list it riner then carefully cure fully manipulate lie the first crystal until the greatest volume Is follow ollo vv title by the tile sec se eo c ond crystal for louder results after a little parellee parc par tice etlee he lie two to crystal crystals can be worked simultaneously till this ain although alt bouch it cannot compare corn pure alah the regular two stage amplifier using tubes alu be free from the tile tube noises of the latter amplifier under good conditions a cretal let set III do very good work alth this unit and the locals mill come in as st strong rong as on the ordinary two tuo lube rege re genera live tire receiver although the ranee of the re ceier ill not he be increased by adding this amp amplifier lifler the annl sign aliss which were dot not audible III be greatly amplified and they will be heard clear ly in the phones without It hout the usual asua usua ning of one a 8 ears if due to the location of the re r aelier one of these units falls to op cip crate a loud pealer speaker two of them theta should be constructed the second amplifier should use one medium ratio transformer and one low ratio transformer it should be connected in the inie time nay ay as the first unit and should be placed after the first unit with its input posts connected to the output posts of the amplifier this tills combination vi hlll ill york very well in any case end and for tile he quiet satisfaction these amplifiers give lve they are well north the trouble of construction hew new lork herald tribune values and also try shifting it froni its present position to one wherein it i Is connected from the grid to the neg anthe or positive filament hew new lork sun plan to test radiation will prove worth while I 1 e since the inauguration atlon of the anti squeal campaign a lot of trick cIr circuits cults are coming out with claims that they do cot not radiate in some instances the claims seem to bare have some basta the best war way to fettle settle beyond cavil 11 whether your set met radiates or not Is to arrange a test with i a neighbor say a block or so way away aree agree on a time for or the test agree off a it wave length or a series of them lent for leaen testing for fr instance la bare your neighbor listen for from 7 to on a night A hen they are on the air tune your set to then force regeneration and oscillation to the limit twist twisting ln the dials and producing all the squeals possible if it the neigh bor bears tears the its time for you to get a real loose coupled radio set or one of the tape using radio frequency alway uway is keep all 11 your parts well separated one of the most important things to bear tn in mind when building a radio receiver Is to keep parts well ell separated st in a three circuit rix eloer which Is made op up of two vario varlo meters and a varlo coupler bad squealing and howling sound sounds will be experienced if it the parts are not well sepa separated rateL and nd in order to prevent this the two vari ome ometery teris should be b placed about 12 inches apart and at right angles to 0 o each other the varl coupler in a three circuit receiver nay way be placed midway between the two vario varlo meters melem separation of set from battery Is not harmful in installing a radio rec receive elvei in a home it Is U often desirable to place the storage battery a distance sinay o 0 14 Is order to make it unseen this can con b done without fear of affecting the ae 0 o trial results obtainable from tile set the length of wire between the latie latter and the battery batterr Is of little importance I 1 in to fact the wire acts a as an additional aerial and often helps along the rego relm tor IN lateana late aaa |