Radio Broadcast (May 1928-Apr 1929)

IN THE RADIO MARKETPLACE News, Useful Data, and Information on the Offerings of the Manufacturer New Receivers Announced THE Crosley Radio Corporation has announced two new receivers; the Gemchest and the Showchest. The Showchest is a console model with a built-in Dynacone loud speaker. The receiver itself is an eight-tube a.c. set employing three stages of tuned r.f.. detector, and two stages of audio, the output stage of which is push-pull using two 17lA-type tubes. The Gemchest utilizes two stages of r.f., a regenerative detector, arid two stages of a.f. THE ATWATER-KENT COMPANY has announced two new receivers. One is the table model 46 set using seven a.c. tubes and one rectifier. This set is priced at $83. The second receiver is the console model 53, priced at §117. The chassis is housed in a metal console together with the new Atwater Kent dynamic-type loud speaker. The price of the new dynamic loud speaker when sold separately is $34. THE COLUMBIA PHONOGRAPH COMPANY'S latest product is the model 950 phonograph-radio combination. This combination includes a Columbia electrical phonograph and a Kolster radio receiver. The price is $450. THE SPARKS-WITHINGTON COMPANY has announced a new Sparton console receiver, type 930, priced at $189.50. This new receiver utilizes the same band-selector circuit used in previous Sparton Equasonne receivers. In the console is also included a Magnavox dynamic-type loud speaker. Tubes are included as standard equipment without added cost. According to Captain Sparks, president of the company, production during the past season was nearly three times as great as during the preceding season. AN A.C.-222-TYPE TUBE is used in the new Series K receivers produced by the Federal Radio Corporation. This set will be available in both table and console models. The lowest priced model will cost $127.50. A 227-type tube is used in the first r.f. stage and in the second r.f. stage a new 222-type a.c. tube is used. In the detector and firstaudio stages 227-type tubes are used and in the output there are two 17lA-type tubes. Miscellaneous New Products THE new Y-227-type detector tube manufactured by the Sonatron Tube Company reaches its proper operating temperature within five to seven seconds after the power has been turned on. This time lag is quite short in comparison with the 15 to 30second lapse for most other heater-type tubes. This company also has a new type 171 ac. tube selling at $3.50. THE C. E. JACOBS MANUFACTURING COMPANY, of 2802-10 N. Kedzie Avenue, Chicago, has developed a new product, the "Repleno" rectifier for use as a replacement unit in electrolytic rectifiers. The list price is $1.00 per jar. These rectifiers are said to be suitable for use in the electrolytic B-power units made by Philco, Willard, Exide, Vesta, etc. THE R. C. BURT SCIENTIFIC LABORATORIES, of Pasadena, California, are the manufacturers of two devices useful in radio engineering. One is the standard Burt PhotoCeil, which, according to the makers, is a highly sensitive photo-electric cell giving a current of 1 microampere per 100 foot candle and a linear relation between 0.1 and 1000 foot candles. The Burt cell is not affected by fatigue. The second device is the Bedell-Reich Stabilized Oscilloscope. The oscilloscope may be used in the varied fields of investigation in which the vibrating mirror or cathode-ray oscillograph is used. THE TRUTONE RADIO SALES COMPANY, 114-116 Worth Street, New York City, has placed on the market the "Si-lenser," a device for use between the light socket and the radio set to eliminate line noises. A NEW DYNAMIC loud speaker switch is being made by the Therm-A-trol Manufacturing Company. This device is designed for use in conjunction with a.c. receivers which are being operated in conjunction with a separate a.c. dynamic loud speaker. By the use of this special switch the power input to both the set and the dynamic loud speaker can be controlled by means of the single switch on the receiver. FERRANTI, INCORPORATED, makes two output transformers designed to connect between the moving coil of a dynamic loud speaker and a power tube. The type op-2c is designed for use with single tubes of all types and the op-4c is for use in push-pull circuits. An article telling how and when to use such transformers will be found on page 194 of Radio Broadcast for January, 1929. PROBABLY THE SIMPLEST way to make it posible to get more output from a radio set without overloading the last tube is to place two power tubes in parallel in the output stage. A device to permit this to be accomplished readily is being manufactured by Arthur H. Lynch, Inc., and is called the Lynch Tubadapta. It consists of two tube sockets mounted in a convenient holder that can be plugged into the power-tube socket of any receiver. The neiv Atwater Kent receiver in a console cabinet with built-in loud speaker NEW LOUD SPEAKERS known by the trade name of Conamic are being made by the Operadio Mamifacturing Company. Various models are available ranging in price from $28.00 to $32.50. Special loud speaker chassis are available for use in manufactured receivers. THE EXCELLO PRODUCTS CORPORATION, of 4820 West 16th Street, Cicero, Illinois, are manufacturers of Excello cabinets for use with all types of radio receivers. There are available also special cabinets designed especially for well-known receivers such as the Atwater Kent, Crosley, Radiola, etc. THE NEW S-M dynamic loud speaker units are being offered in two models; the type 850 for a.c, and the type 851 for d.c. field excitation. Hum in the a.c. model has been eliminated by supplying the field with 120 volts from a 280-type full-wave rectifier. Across the output of the rectifier is connected a 2-mfd. filter condenser which, in conjunction with the field coil, completely filters the output so that only pure d.c. flows through the field winding. The loud speaker is equipped with a 229-type coupling transformer so that the loud speaker may be used with all types of tubes. The 850-type a.c. unit is priced at $58.50 and the 851-type d.c. unit at $48.50. Only the loud speaker unit itself can be obtained, i.e., they are not sold in cabinets. Radio Industry Briefs WITH the sale of station wabc to the Columbia Broadcasting chain, the New York offices of A. H. Grebe and Co. have been moved from West 57th Street, New York, where they were combined with the offices and studio of wabc. The Grebe executive offices are now at the factory in Richmond Hill, Long Island, New York. HAL P. SHEARER, formerly general manager of the Sphtdorf Radio Corp., of Newark, N. J., has been chosen vice-president and general manager of the new Sleeper Radio and Mfg. Corp., Long Island City, N. Y. A. N. Clifton, formerly sales manager of the Alden Manufacturing Company, is sales manager of the reorganized Sleeper Company. GUY C. KOWFELDT, 529 South 7th Street, Minneapolis, Minn., and E. F. Coughlin, 10 High Street, Boston, Mass., were recently appointed district managers for the deForest Radio Company. They will cooperate with jobbers and dealers in their territories. ALBEBT L. SCOTT, formerly with the Girard Phonograph Company, Edison distributor in Philadelphia, has been appointed manager of the Atlanta, Ga., branch of the Edison Distributing Corp. MERWYN HEALD is the new chief engineer of the Thordarson Mfg. Co., of Chicago. Mr. Heald was formerly chief engineer of the Robertson-Davis Co., of Chicago. The new Thordarson executive was graduated in E. E. from Northwestern where he was a member of both Signa Xi and Phi Beta Kappa. Thordarson has also announced an increase in their factory space and additional research and production is now contemplated. THE GENERAL CONTRACT PURCHASE CORP., New York, has issued the third edition of their catalog of R. C. A. • aprit, 1929 page 406 #