OCR Text |
Show Tubes, Power Hanc5Iers, Not Power Producers Power tubes are power handlers, not power producers, as many think. Of itself, a power tube will not produce pro-duce more volume than a nonpowcr tube. Its design permits it to handle greater volume without distortion. Most receiving sets are capable of delivering more volume to the last audio tube than can be handled without with-out distortion by the. usual types of amplifying tubes. This Is where the power tube Is neededin the last, audio stage only, where it can receive the volume developed in the earlier stages of the set and pass It on, amplified am-plified but umlistortn.l, to th; loud speaker. The electrical characteristics of power tubes are iuile different from those of the customary amplifying tubes. Power tubes consume more "P," battery current and they require greater "C" battery voltage. The wrong "(,"' battery voltage robs the piiwer tube of its ability to bundle greater volume without distortion, resulting re-sulting in operation little, if any, better bet-ter than ordinary tubes. In addition, if the "C" battery voltage is too low, the "" current consumed by the tube is multiplied many -fold, which rapidly exhausts the "11" battery. Merely substituting sub-stituting a power tribe for some other tube in the last audio stage of a receiver re-ceiver will not bring about any noticeable notice-able improvement in reception. Pro-Vision Pro-Vision must be marie in the wiring of the set to allow placing the current value of "("' baltery voltage on the grid of the power tube. The newest power tubes are OX -.'171 and UX-171. These lubes can be operated op-erated oil "V," buttery volti'.SOH f !l ' 3.15 or ISO volts. The uliioinit' of tir,-distorted tir,-distorted power which these lube.- can handle when working at V-i'j vo'ts of "I! " 'J:lU'--",' I 'n mow e: !. iooi-o ttlon can cOttfCrlid.'!1 V; u--et.l i'i average home. It is only wheli 'm-usual 'm-usual volume Is desired, such as to enable t crowd, to d:ince In it '".'.'ge ball, that the eMremu vWAse of l.vi volts Is require:, l'ir liome ns,; I J.j volts of "P," he'sii'Vy is ample for the CX-17! 1 o.or tubes. With these lubes, whim the "P." lottery lot-tery voltage Is l,",o volts, the "O" battery bat-tery voltage should be L'7 volts. A new U'JVs-vnlt battery lias been intro duced by one of the largest manufacturers, manufac-turers, and when connected hi series with a -I'i-volt "O" buttery the combination combi-nation will deliver the "7 volts required re-quired by these power tubes operating at l.'k" volts of "P," battery. The extitt powvr handled by p,.wer tubes is furnished by Hie "P." buttery, mid hecau.ie of this tl'.ey should never be operate:! from light duly bat tciies. Use only the heavy duty sb.e of good, reliable make, and be sure to Use the correct "(."' battery voltage. |