Radio age (Jan-Dec 1925)

76 RADIO AGE for December, 1925 The Magazine of the Hour RADIO AGE ANNUAL FOR 1924— AT SPECIAL PRICE! Clip the coupon and send it with 50 cents, and the RADIO AGE ANNUAL FOR 1924 will be sent you by return mail. 1 1 1 1 I Addrcu 1 1 . 1 L__ __ ___ __J Christmas on the Air! — are Your Tubes In Shape? At Christmas Tide! Listen to sweeter "Christmas Carols" — clearer chimes and more celestial music broadcast by the great cathedral choirs throughout the land. A Rhamstine -k TUBE BOOSTER will renew your old tubes with all the pep and freshness of new ones. Just put them in the socket and turn on the current — do it once a month — it will treble the life of your tubes and give you better distance, volume, and a tone as clear as a bell at all times. It will pay for itself in a few da,ys. Works on any alternating current 110-120 volts, 50-1 33 cycles — 201-A or 199 Type Tubes. Send no money — check the coupon below — pay on delivery. Rhamstine* "B" Rectifier (Eliminates "B" Batteries) Price Only (Tube not included) 'liminates all your "B" Battery troubles such as recharging, dead cells, and chemical action. A Rhamstine* "B'\Rectiner will more than take the place of a "B" Battery — it will give continuous and uniform current year in and year out with absolutely no trouble at all. Small, compact, good looking, endorsed by the leading radio manufacturers, and reasonably priced. You should have one. Send no money — just check the coupon. Tube Boosters are Trade Boosters. DEALERS — write for our attractive proposition. X J. THOS. RHAMSTINE * (12) 504 E. Woodbridge, Detroit, Mich. Please send me Rhamstine Tube Booster at 56. Rhamstine *'B" Rectifier at $25. by express C. O. D., subject to inspection. If not entirely satisfied with the "B" Rectifier I will return it to you in five days and receive a refund of full purchase price. Name Address J. THOS. RHAMSTINE* Radio and Electrical Products 504 E. Woodbridge Detroit, Mich. Grid Leak and Condenser Now Combined One of the improvements in radio devices brought out this season is the new Daven "Leakandenser," an unique device which combines in a most attractive form, a grid leak and a grid condenser. The Leakandenser attracted considerable attention at the recent New York Radio Show. It is similar in size and shape to the conventional cartridge type of grid leak, with metal end caps, and may be mounted conveniently in the set by means of two spring clips supplied with the unit. In construction it consists of a hollow bakelite spool, within which a Daven grid leak is suspended. Each end is threaded and fits into a nickel plated terminal cap. Around the outside of the spool, and connected to the end caps, is the grid condenser, which is formed by two separate and insulated wires, wound parallel in a single layer. One wire connects with one terminal and the other with the other terminal; each wire of course having its other end open. There being no physical contact between the two wires, they form a condenser, the capacity of which has been designed to be just right to function properly as a grid condenser. Grid condensers in the past have been criticised for their lack of uniformity in capacity, their susceptibility to injury during soldering operations and the tendency to alter in capacity under various conditions after installation. These troubles have been remedied in the new Daven unit by the unique method adopted to obtain the condenser effect. Leakandensers are made with five different values of grid leak — 2, 3, 4, 5, or 7 megohms, so that a selection may be made suitable for any detector tube. The Leakandenser takes up less space, is infinitely easier and more convenient to install, and makes the set look better. New "A" Power Unit Made by Gould The Gould Storage Battery Company, 250 Park Avenue, New York, are now placing on the market a highly perfected "A" power unit which they term Unipower. It is not a battery eliminator but is an "A" power unit that automatically converts house lighting current into radio power of constant, full voltage. It is a single compact unit, enclosed in a beautifully finished gas-tight case that fits comfortably and safely inside most radio cabinets. There are no tubes, bulbs, lamps or working parts that require frequent replacement. A single master control switch operates both the radio set and Unipower. When the radio set is on, the house current is off — when the set is off, the house current is on. It is impossible to damage Unipower through the failure to add water when necessary. When this happens, the charger automatically cuts off and prevents harm to the battery unit. Unipower is supplied in the models for 60cycle, 110-125 volt A. C. Each model is equipped with a Baklite charger of special design. Models are also made of the 25-50 cycle lines. * Tested and Approved by RADIO AGE * January Model Receiver Will Be a Revelation Order Your Copy Now from Your Newsstand CONDENSERS VERNIERS RHEOSTATS AMSCO PRODUCTS. Inc. New York City EFFICIENCY That Meet8 the Requirements of Eminent Radio Engineers Apex Vernier Dials are more than mere "knobs." In reality they are instruments endowed with an ultra degree of efficiency. Their rich elegance of finish lends a touch of striking attractiveness to any set. Precision of production and of operation makes a good set a better set — providing greater range of selectivity — positiveness of control — and utmost simplicity of tuning in most difficult stations. Ratio 12 to 1. Clockwise and counter clockwise. No back lash. Royal Brass finish 4-inch $1.50 — 3Viinch $1.25. Satin Silver Finish 4-inch $1.75— 3i/i-inch $1.50. DeLuxe Gold (24K) Finish 4i n c h $2.50— 3Vi-i n c h $1.85. Your dealer has them. If not, order direct. APEX Rheostat Dials are essential to successful operation and pleasing appearance as are Apex Vernier Dials. Royal Brass Finish — 60c. Satan Silver Finish— 70c. DeLuxe Gold (24K)— 80c. APEX ELECRTIC MFG. CO. Dept. 1211 1410 W. 59th Street CHICAGO