| Show 4 by 4 0 3 douglas Ward rov editor of 0 radio merchandising ca ga ca 7 RI ra ra 4 x r 8 A 35 diagram showing amplifier alone wired to plug by single lead arrange merit ment suggested for adding Fles istance coupling to any circuit resistance e coupled audio amplification la Is rue meeting eting with popular favor wherever it lins has been tried it reproduces over tile entire scale without t distortion of any kind its only drawback I 1 Is 3 that throe stages binges are nee to produce the volume of two of transformer coupled amplification cst lon the diagram shows how a re stance coupled amplifier coabe added to any set the coupling re sisters rl of the A F V amplifier tire ire ohra this value remains tho the same for till all tubes practically as do the DM mad coupling isolating condensers CL the grid leaks 2 ra and ra have respective active values of I 1 meg olim and 14 megolia meg lira olim the diagram shows the tha amplifier lone glone wired to a plug by a single lend which arrangement Is 13 suggested for adding resistance real stance coupling to any circuit practically no knowledge what yer of the rec receiving circuit Is feces sary ry wire X should be tripped tapped on 45 bolts of B D battery after tuning la in a station on telephone receivers the phones should bo be removed and tho the amplifier plugged into the jack if no signals are heard beard the single wire leading to the plug should be b transferred to the other plug terminal when signals ure are betag being amplified X should be varied over the B battery taps until the response to is tho the strongest without impairing impat ring quality transformers Transform era can be used fihe amplifier should always bo be plugged late the lowest stage jack on the he receiver proper the jack that or ar din artly gives the tha weakest response many neutro dynes are so arra arranged nied that at least orie ony stage of transformer coupled dudlo frequency amplification must bo be employed this being tile tho case no more than two stages or of resistance si coupling should be added ono one extra step generally v will suf suffice lice quality probably will not suffer through the single stage of trans former coupled intensification properly designed and operated ono one trans coriner coupled stage singe should bo be andl lively perfect if tire the receiver to which you contemplate tile tho addition of resistance coupling Is a fhe tube set bot and four tubes are used lighted on tho the lowest jack it to Is an indication that ona transformer coupled stage la Is being employed high voltage la Is necessary when putting inputting in from the detector tube from 45 to CO 60 volts should bo be applied to tho the plate pinto of this bulb compensating as usual for the voltage drop across tile the coupling resistor in the plate circuit no more than 90 volts should be impressed on the r f circuit while volts or more should be used on the a f amplifier amp lifler this last will function satisfactorily on go 00 volts though higher la Is quite naturally secured on the increased volt vol tego ngo lien inputting in putting from a transformer coupled stage the normal detector voltage should be used it if only two resistance coupled tubes are used the tha leak values should be ah and U respectively if a single stage Is employed the grid leak should bo be a ohm resistance si st the UV the 0 and tho the deforest DV 2 tubes will function satisfactorily in this amplifier |
