Radio Digest (Jan-Oct 1926)

RADIO DIGES T— Illustrated arade of q/j (Eliminators LAST ISSUE we displayed the season's latest offerings in receivers. Next issue loud speakers mill be featured, but here we have "The Parade of B Eliminators." And a big parade it is, too, for manufacturers upon manufacturers have taken up the popular problem of lighting current B supply. In apportioning these pages, the problem of classifying A eliminators with B substitutes was discussed, but it was decided to feature trickle chargers and A eliminators in a later issue. So we have below, paraded before you, ten of the 1927 B eliminators which should enjoy a good sale. Their specifications are given insofar as data is available, and their prices may be learned by interested parties merely by writing a letter to Radio Digest.. Nowadays, the "A.C." or power hum has been practically done away with by most eliminator makers. This has been accomplished by careful design and addition of improved filter systems. This year's B eliminators also will be observed to have provided for heavier voltages for powitr tube operation. Grid bias or C taps have been added, too. Three new models of Majestic B current supply units are being offered. The model at the right is known as the Majestic Super-B and supplies a maximum of 45 mils at 150 volts, or sufficient to operate sets up to 12 tubes, including power type tubes. Detector and intermediate voltages are variable, and a switch is so arranged that the lighting current can be cut off. Standard-B, less expensive, is designed to operate seven tubes and Master-B, the largest of the Majestic family, handles anything up to 60 mils draw. All use Raytheon tubes. And here's the brand new Freshman A-B-C Power Supply (at the right) which leaves nothing to be required but a storage battery. The Freshman device embodies a one ampere Tungar trickle charger with a UV-213 type tube full-wave rectifying B supply. The latter is arranged to give a C voltage of 9, and B voltages of 22J/2, 45, 90 and 135. The builders of Freshman Masterpiece receivers designed this A-B-C unit for the purpose of building it into their cabinet model sets, but there is no reason why the A-B-C Power Supply should not be used by anyone having a set with from 5 to 8 tubes. . Even Frced-Eisemann are in the B eliminator business, but just to keep their line complete. The eliminator they make is really a B and C substitute, and is shown at the right. It will operate all Frced-Eisemann 5 to 8-tube receivers, or others having the same pozver requirements. The unit yields C voltages of 27 (for special pozver tubes), 9 and 4ZA, and B ■voltages of 45, 90 and 135. Another feature is that the ■unit is shockproof. The Kingston, bclozv, sells complete zvith Raytheon tube. Three voltage taps arc provided, and these are variable over a wide range of from 5 to 150 volts. Sufficient plate current is provided to operate any receiver up to ten 201A tubes or equivalent. The case is finished in black and nickel. The Poweriser, left, is ' something new in that it combines B eliminator of high order zvith an auxiliary stage of super-power amplification, so thai older sets lacking the nczv style pozver amplifier may be brought up to. dale without any rewiring. Pozvcrizer supplies up to 170 volts of B pozver for the set, 350 for the pozver tube, and A and C pozver for the pozver tube. Top left and top right corners of the page shozv two nczv members of the Balkite B eliminator family. They are chemical, of course. Top left is model W, low-priced and made to supply sets of 5 tubes or less requiring 67 to 90 volts. Has separate tap for detector tube. Top right is model Y, and it is designed to supply any set, including the largest now on the market. Pozver tubes are its "dish" and it has enough volume to fill a hall. Intermediate taps for smaller sets arc provided. Output, 40 mils at 150 volts. Model X, which comes between the two described, is for sets of from 5 to 8 tubes where 90 to 135 volts arc required. Output, 30 mils at 135 volts. Balkite "Combination," another new device, combines Model X with a trickle charger. Directly above, in the second row and proudly displaying the "B-T" trademark, is the new Bremer-Tully B-powcr unit. It is a Raytheon type rectifier, and is designed very evidently with the idea foremost in mind of making it foolproof. Its output voltages may Invaried by changing cartridge resistances within the case, but for the standard set these arc set at 22l/2, 45, 90 and 135 volts. A little adjustment plug on the front controls the output current, which can be adjusted even as high as 60 mils at 155 volts. Radigon, left, will operate any set up to 12 tubes, including pozver tubes, and is compactly assembled in a case finished in green Duco. Three voltage taps arc provided and the detector and intermediate are adjustable. A high and low switch is also on the panel. Rectification, is accomplished by a gasfilled full-wave type tube sold zvith the Radigon. Neat, compact, and powerful, the B eliminators made and sold by J. Andrew White, famous sports announcer, supply smooth and even B current in a variety of z'oltages. The smaller model is shown at the right and has a maximum voltage of 135. Just introduced , however, is his Superpower model, which provides a maximum voltage of 200 volts, zvith variable taps. The White eliminators are of the electrolytic type, and use double the usual number of rectifying cells.