Radio Broadcast (May 1928-Apr 1929)

THE COMPLETED A-B-C-POWER UH1T Assembled from parts generally available this A-B-C-Power unit may appeal to many constructors who have a good receiver which they do not wish to discard but who still would prefer to displace their battery supply and provide a modern last audio stage An Interesting A-B-C-Power Unit and One-Stage Amplifier By J. GEORGE UZMANN Dubilier Condenser and Radio Corp. SAY Frank, I have a radio problem on my hands, and knowing all the time you've spent on broadcast receivers I thought perhaps you can help me out," was the way a friendly chat began. "Surely, only too glad to be of service," and his friend inquired, "tell me all about it." "Well I suppose I'm just like everybody else these days and want a completely electrified set. But in a way I hate like blazes to scrap my Neutrodyne which is just a little over a year old and tunes about as fine, and has tone quality almost as good as any I've heard; still on the other hand if it isn't the B-battery going bad why then it's the old storage battery quitting at just the wrong time. Yes, I suppose my trouble is simply batteries, batteries and then more batteries. "Frank, tell me," he continued, "what make of electrified set would you buy? I can't make up my mind on this point, but it seems to me as though the cheapest receiver in the electrified class costs about $125 with tubes, if the ads mean anything at all. My present set cost a little over $175, and to think there is a 100 per cent. depreciation to be taken after a year's operation is hard to believe — that state of affairs surely would not get by in everyday business." "Just a second, Lawrence; pardon my interruption, but I think 1 pretty well understand your problem, and if you will let me tell you of my experience along these lines during the past THE complete power unit supplying all receiver voltages and containing a type iji audio amplifier stage described here is an excellent unit. Tested in the Laboratory of Radio Broadcast on a standard battery-operated receiver, very little hum was audible on a high-quality loud speaker. Home constructors may be interested in duplicating this unit for it is highly satisfactory and comparatively inexpensive. The professional setbuilder and service man will find in this device a popular replacement outfit for the power supply of battery-operated receivers with an insufficient laststage audio amplifier. — The Editor. -T year, or say, ever since this a.c. tube question made itself felt, then perhaps you shall be better able to purchase the correct type of set or equipwith not only the least cash outlay but also without running into the usual grief." The radio expert with these few words had the pulse of the situation. WHAT IS AN ELECTRIFIED RECEIVER? THE above paragraphs in a few words describe the general thoughts and impressions which exist to-day in the minds of many who now own radio equipment. Gaining momentum, it seems as though everyone is interested in an "electrified set." Yet strange as it may seem, very few people really realize just what sort of a set it must be. Evidently any receiver is "electrified" just so long as it operates without batteries. A radio trade paper recently made a canvass in effort to learn just what the public was thinking about regarding "electrified" equipment, and it is interesting to note that less than 10 per cent, of set owners had any conception at all about what 145