Show lm P 6 M 1 1 1 1 0 L H W a OW V F the tha wiring diagram of the tha by SIDNEY E finkelstein in ne new w york herald tribune the honors in audio frequency am seem to be divided more or less evenly between the transformer and the resistance coupling methods each system antem has its stanch adherents who are ever ready to nine fling masses of facts figures and fancies into each others faces whenever a of relative merits arises the transformer supporters are just BS as firm in their belief of the superiority of their instruments as the resistance hench bench men inen are in ili their views on tile the advantages of their devices the writer has haa used both transformers and in the construction of a largo large number of sets aud and after studying the geri general eral results 0 ob twined from them has come to tile the neutral conclusion that both systems pre fire good but that they aro nr even better if they are combined in the journalistic nalls na listic tle fashion to the of the best beat features of each the advantage of the greater amplification per stage afforded by tile the transformer combined with the flaw less reproduction but lower amplification of the resistance makes tile the ideal lom combination in the majority of acts A complete amplifier amp lifler of this thin ad vant ageous type can be mado made at home at surprisingly little trouble and ex pense and once on hand it finds application pil cation to receiving circuits of fill all kinds it may be built permanently into a beet or it can be left available as aa a separate unit for connection experimental tuners for the tha last purpose it Is especially convenient as it saves the constructor of a new nev set sei the worry of providing oroal to follow the detector tube parts required red an amplifier such as the one shown in the illustration will require the following parts which can be purchased chased tit at any radio store hard rubber or composition baseboard 12 inches long 4 inches wide and 14 inch thick one heavy audio transformer vot not above 8 3 to I 1 ratio three standard tube sockets two resistance cou pling units with two one and one ohm resistors one mad fixed condenser eight binding posts and the usual bulbar and mounting screws A definite assembly procedure should be followed first the general location of the instruments should be determined and all the necessary screw icren holes made in the panel before anything Is fastened down permanently the devices should be pushed closely together there Is no danger from howling as there Is only one transformer so as to allow room on an the right and loft left hand short edges for input and output binding posts the wiring will give s lve no no trouble As an a start the P and aind ID B posts of the amplifying transformer should be connected directly to the two binding posts on the extreme left which are designated as the input ter finals the niad fixed condenser Is isalio also placed across the wires mires and can be hidden comfortably out of way beneath the bottom of the bas baseboard Noard of coarse small holes will vill have to be drilled irr iff the composition to pass the wires wherever necessary ow essary the th filament posts post next the filament posts of 0 the three suck sockets ets which are all marked P ore are wired as shown in the diagram and lead finally to the A battery binding posts these should bethe be bo the left hand two of thi the row of four along the long edge of the baseboard avith this much done the second secondary ft of the transformer can now be bb wired to the grid and filament lament fl posts of the first tube socket progressing across the condenser end and resistor terminals st re wired in tho the manner indicated in the hookup hook up with the resistor units that were employed in this particular amplifier the ing soldered labs of the spring mountings ings malco make the placement of the wires a 0 short and simple task the two posts on an the extreme right are re the output to one li ran a wire aiom rom the P terminal of the mhd last bocket andio the other a wire from the D plus pills post which la is imm immediately id adjacent Jacent the A plus and 13 minus posts it will denoted be noted are anro joined together all the wiring should be done with round or square tinned bus bar the wire need be insulated with cambric tubing only in places where here two wires unavoidably pass each other very closely very little covering will bo be found necessary noce the connections to the transformer tie the 6 aub U lai wyck buckets ets and the blAding boits T r amplifier herein described which are all equipped with strong screw binding posts need not be AoI ol derod dered but those to the fixed fired con donders and the resistor mountings must be the B D battery should be of am volts volta which Is the standard requirement for resistance amplifiers with this voltage the ohm resistors real stora should bo be employed in the pinto circuits caits of the first two tubes while the ohm leak goes between the first drat and second bulbs and tile the ohm resistance between the second and third in the grid leak positions this Is clearly shown in the g diagram |