Show zdith by 0 st radl c E HAMANN experiments while in wing the n hp r new principles 1011 or theories V pless P interesting to way I 1 I 1 set t listener particularly the when u a litt little ie variety in the evening 11 1 is I aror required ie in a two ill all tic fie I 1 p i amplifier a ingle single hend head n I 1 a loud speaker a single phone hone L I 1 it horn orn attached to it III cof abow i do a fora for I 1 1 ia I enker 1 ihunt t no I 1 connet the for to the input terminate of f bead a V her iler I 1 e across the primary the R of i tip r audio transformer I 1 ight tie tu u nd PS plug in the loud iphill er on the second d stage in the usual r h sketch hold the clinti teed i no mith v alth land cupped aronna it to f a mouthpiece and talk into it in 0 v 11 voice the oice olce will III bp fl i in the e loud speaker with greatly volume the render reader can anally think of a doten different vay mays of amusing him alf wilt tills at his hi next party set avo to ali J how now to connett the apparatus for the th experiment experiments described in 1 this article lp vp the loud speaker la in the parlor there where the guests are assembled and rag a long telephone cord to the radio set et in some other part of the house tune in a selection from some local broadcast station and plus plug in the loud speaker at the end of the selection switch off the detector circuit and do your own oin announcing dising the A tubes use less current than old style thousands of broadcast listeners who baie haie radio receivers consisting of detector and two stages of audio fre aenny amplification are still using the original ll 11 L tubes purchased when they installed their eti sets these tubes etive been superseded by we UN Vs thich which consume much less current than the old style tube tubes consequently when the inevitable change Is 19 made to the new tubes a greater resistance bust must be provided la in the rheostat rheostats if it the tile amplifying unit has his a rheostat for eich each tube as a Is usually the case there aw f J how the low resistance rheostats of a standard amplifier are connected up to be used with A vacuum tube tubes 13 I 1 a 1 timple simple way to do this without sub new rheostats adding OU outside aside or changing the appear mee of the get sel audio frequency amplifying tubes are re not critical one control will therefore do for both tubes remove remover all conn conflicting Wing wires from both rheostats except the current supply 1 wire to the first rheostat con liecbt he the rheostat rheostats together as shown bridging brid eing across the adjacent posts with bus us wire or if more resistance la is want td thin than Is afforded by the combined rheostats with a section of resist ince wire from a discarded resist me ice unit unil A connection Is then run from the remaining binding post of att joined rheostats to each of the two sockets taking the place of the original ori rinal connection connections the combined ot of the rheostats will make the proper re 0 lance lt nce allce tor for two A tubes when con acted in this tills manner besides allow his lag ample varla variation using cither either or both knots knobs to secure brilliancy 01 of the till filaments ue use proper tube in right place in set it has often been said that no two pitches itches run alike this can be ex tided wed to take in vacuum tubes een to it 1 eater peater P degree there are hun hurt drad Ms I 1 of things that may make one rubt atlon t tt lon differently from another true e as its it may be that a soft or w tube will make a better de lector it has been proved that some hotd ard tubes bes are unexcelled for deon aten whee e a 0 soft tube was blended in the original hookup lt IS quite probable that some of the tube tubes it 1 your 0 set are better suited for dette tore torL it Is also oft that your reaul results g might be bet b I 1 placing the tube now in the state of audio la in the first stage and vice verge 1111 1 lc lastly other things in radio this belt by actual test the pl 11 em that arises during these tests it 1 lilly be to deter easy enough allio a vilich tube works best here and ija one work works best there but ho laii station on api I 1 glar ihrl aum ill al it 11 or of llon duin atif uk wk in I 1 0 atif e limit the effe t on oil tic tip no ili no e will be startling to 11 ilir titi am AS in allow low pr amt inake cuip ui list flere it ere tire no n hard I 1 olim I 1 finlo an i 1 nit tl it a pixie HI ml link nirl sturt a rl t letting Ift ting hok gilmin 1 1 lie it P it titio up it 1 it 11 hinlle unit till r 1 a unit oil 4 une I 1 it fire i rs if oin peon iv I 1 ll 11 e a sat k t I 1 if Io irr it 1 un mi lit lo in lit tuii lir simi ml 40 in t etli walli ii HP p it III ti 11 t it 11 tim tv iran it in tin file f r ii P iret itil till r an I 1 bri ij them out to tl it p I 1 I 1 ap wl A I 1 lil I 1 I 1 I 1 ili t 0 awil nn not n trun knitter A ati Ipp lep lion lione in ik k annl an I 1 I 1 luc ing 1 l III n pliay ti tic P 1 r in i binl n I 1 put f the cir lr lit I 1 of a d 41 lible I 1 p ir dpn cirull jacb till tills cnn ann in ho laff vonn bonneted eted to t tie tl mit t 11 in 1 it will n t nt I 1 H aitio ln n in any WB wit exist hen the hood phone iq plugged iEK in if it iron ampt program 14 1 boing being re 1 I 1 and it k 1 desired to interject I 1 little 1 tt ao 10 homemade announcing fir first cut off the detector circuit by turn ing the detector rheostat to the off position and then plug in the licad head clione transmitter another similar experiment which produces rather unexpected results cong consists lists of connecting the loud speak er to he the input tide aide of the amplifier and listening with a pair of head phon phones plugged into the second stage the loud speaker will act as ft microphone and pick up any bounds produced near it ohp thee te will be simpli fled and reproduced in the head phones with tremendous volume it the loud speaker li Is located in some other part of the house houpe it will pick up voice voices from the etame room and reproduce them in the head phones as clearly as though the listener were in the room where the person n as sp ealing this lat last experiment mav highly entertaining if conducted on a it ednes dT canine when sitter sisters beau Is I 1 calling radio news aws Is a fan to know one tube from another if the tubes happen to be removed from their sockets at ony any time the answer to this Is quite simple before coing going about the test set up a list of symbols as follows radio frequency amplification R detector D I 1 audio frequency amplification A then add numbers where more than lie tube Is acting in the same capacity thus if you have a five tube set using two stages of radio frequency amplification detector and two stages of audio frequency amplification the symbols will read as follows R 1 R 2 2 I 1 D A al I 1 aa set up these symbols go about the test end after you have found the best combination for the tubes start from left to right in your set get and remove one tube at a time aith ath a pointed in strument ment scrape the symbol on the bottom of each tube As A far as the test itself Is concer concerned dont don t think wu i ou can complete comp lete it to fit teen minutes how spiderweb coil I 1 mounting can be made by 0 L L VAN DYKE JR hie ilie fol following loing together toe ether ith the illustration is a description of an 1 ex cellena form of spiderweb spider web coll coil mount ing probably the moot most Impress he lill feature of this tills arrangement la Is its compactness compared to other mount arm the construction ie Is simplicity itself and the parts required are few inferring referring to the aleth A Is a knob and end dial B la is a pl alioe of limsi or phosphor bronze bent 0 0 as to f rm 4 fee 1 r detail details of the spider web coil mount form forms can Os ma ing the coll of any good insulating material support for the coll and 0 sir oft ft C li 14 a g I 1 uri um lag ing hi it ewe es to to pro vent shaft 1 D from gilding eliding gildi nl the stun starl 1 I 1 inch labassi and at abnit lut in hs h Is a R till tali P end to its silt slit near long longwith with a web ul oil f rm 1 the end of the spider II 11 f nn rin second base of the F Is the 11 the hnud ird attached to al ich Is ket 0 0 sin e ilir tilt fl till brac bracket brass b by y a no trou brou rolls tire not heavy web d der er need in baan ing ble should be export f cill rill if the A ohp balance Is too atea a counter the coil coll en enl I 1 if it the upper be I 1 to may shown at J 1121 iladio tio new lewe he the form as is removal of or tubes the 11 connection connections changing detore e al should the bulbs t to a act set careful removed the most nays vi eye be allow chort sh ort circuit circuits to t of radio fan fans Is lat connect connection lon if the and find even occur instant it ie 13 usually mug only an bat bet if the B D to blow the bulbe bulbs 00 out t deriel or art la in the circuit |