Radio Broadcast (May 1929-Apr 1930)

IN THE RADIO MARKETPLACE '"""""-pf News, Useful Data, and Information on the < — """"" ^^^^asa^ Offerings of the Manufacturer ^*»#***^ New Receivers Announced The Ware Manufacturing Corporation is the maker of a new receiver incorporating a band-pass amplifier to obtain sharp tuning without sacrificing the fidelity. The r.f. amplifier uses screen-grid tubes and the output stage employs a 245-type power tube. The table model lists at $195 and the console, which contains a dynamic loud speaker, retails at $425. The C. R. Leutz Company has announced the Seven Seas Console Set. The set consists of three stages of tuned r.f., a detector, and one stage of a. f. Screen-grid tubes are used in the r.f. stages and two 210-type tubes in push pull are employed in the output. In the console is incorporated a dynamic loud speaker. Radio Receivers for operation on 32volt farm-lighting plants are being manufactured by the Federal Radio Corporation. The farm-lighting system supplies current for the filament and ordinary R batteries must be used for the plate supply. These sets are completely shielded and use the same circuit as is incorporated in the Federal sets, models e and f, designed for 110volt a.c. operation. Prices range from $100 to $325. The Federal Orthosonic Model m is an all-electric receiver using five 227-, two 245-, and one 280-type tubes. The receiver is shielded thoroughly and each plate lead to the r.f. tubes is filtered by resistors and by-pass condensers. The set is equipped with a "timber" control which permits the user to vary, to some degree, the characteristics of the audio system. The Continental Radio Corporation has announced three new designs of "Star-Raider" receivers, models r-20, r-30, and rp-40. The Technidyne circuit is used in a chassis consisting of seven 227type tubes, two 250-type power tubes, and two 281-type rectifier tubes. An automatic line-voltage regulator is included in the power supply. The set has two dials, one a station selector and the other a volume control. A phonograph pick-up jack is provided. All models use a 14-inch dynamic loud speaker. The American Rosch Magneto Corporation announces three new receivers which have been designed to use the a.c. screen-grid tube. All three of the sets will use the same chassis which employs three screen-grid tubes as r.f. amplifiers, one 227-type tube as a detector, two 245type tubes in push pull, and a 280-type rectifier. The table model is reported to list at $119.50, the combined set and loud speaker console at $168.50, and the De Luxe highboy at $240.00. Miscellaneous Apparatus The Master Engineering Company, of Chicago, is the maker of a complete series of hr_e-voltage control devices. Units with the capacity of either 60 watts or 100 watts may be obtained, the 60-watt size being generally suitable for use in such sets as the Atwater Kent, Radiola 18, Crosley, Philco, etc. 148 • The 100-watt size is especially adapted for use with radio sets utilizing dynamic loud speakers such as the Majestic, Radiola 62, Sparton, Zenith, Kolster, Fada, etc. The 60-watt unit sells for $2.50, and the 100-watt unit for $3.00. A variable resistance capable of handling 20 watts and having a range of from about 40 to 10,000,000 ohms is being made by the Pilot Electric Manufacturing Company. This new resistor, known as the "Resistograd," will withstand potentials as high as 500 volts. The retail price is $1.00. Other resistors are made in sizes as follows: 0-50,000 ohms, 0-100,000 ohms, 0-200,000 ohms, and 0-500,000 ohms. These latter resistors will carry 0.125 watts and sell at $1.50. The Dubilier type 688 filter condenser is rated at 2000 volts d.c, 1500 volts a.c, and is designed for use particularly in conjunction with the a.c. mercury-vapor rectifying tube which is frequently used in small transmitters. Electrad, Incorporated announces two new products, a 5-watt high-resistance volume control and a complete line of wire-wound covered resistors. The new volume control measures 2 f5 by 2 y§ by § inches deep and is one-hole mounting. It incorporates a graphite resistor element fused to an enamel base. The volume control may be made in any desired range and either of uniform resistance or tapered to meet specifications. The new Electrad fixed resistors are made in various sizes from 7.5 to 100 watts with various values of resistance up to approximately 175*, 000 ohms. The nicklechromium alloy which is used for the re 77it> new Bosch console receiver shown above has three screengrid tubes and a dynamic speaker connected to the output of a push-pull stage. The cabinet has sliding doors. • JULY • 1 929 • sistance wire is wound on a piece of refractory tubing and is covered with an elastic enamel. New type volume controls, balancing condensers, and small molded condensers are being made by the Polymet Manufacturing Corporation. The volume controls are made in various values of resistance. The molded condensers contain two insulated mounting holes and measure j by fi by i inch. A unique " Rainbow" dial is being manufactured by the National Company. As the knob is turned various colors in turn illuminate the face of the dial. Other new products announced by this company are a tuner, type mb-29, which uses four a.c. screen-grid tubes and the new "Velvetone" amplifier. The latter device is completely a.c. operated and uses two 245-type tubes, one 227-type tube, and one 280-type rectifier. Another new product is the National Polarizer, a unit designed to supply voltages to condensertype loud speakers. It lists at $12.50. A DYNAMIC LOUD SPEAKEB IS being made by the Transformer Corporation of America. The diaphragm is one piece of large diameter. Special construction permits the elimination of the suspension spider at the apex of the diaphragm. These loud speakers are furnished to manufacturers with and without rectifiers or transformers. Special field coils are supplied to meet individual requirements. A new device, the Plugairial, is announced by the Consolidated Corporations of Chicago. The device is designed to plug into a light socket and connection is provided for the antenna. List price : 85^. Hems of Interest r~W m: Aluminum Company of j America is prepared to furnish I aluminum sheet of high purity, ordinary commercial purity, and in the form of various strong alloys. This material finds frequent use in radio receiving sets. The company also manufactures aluminum foil for use in fixed condensers. Complete data on the products of this company may be obtained from any of their local sales offices located in the following cities: Albany. N. Y.; Roston, Mass.; Ruffalo. N. Y.; Chicago, 111.; Cincinnati, Ohio; Cleveland, Ohio; Detroit, Mich.; Indian apolis, Indiana; Kansas City, Mo.; Milwaukee, Wis.; Newark, N. J.; New York, N. Y.: Philadelphia, Pa.; Pittsburgh, Pa.: San Francisco, Calif. ; St. Louis, Mo. ; Toledo, Ohio; and Washington, D. C. A microphone for use in broadcast stations is being distributed by the Gotham Engineering and Sales Company. It is of the two-button type with a solid back and uses a stretched duralurninum diaphragm. The unit lists at $75, or complete with ring desk mount, covers, and cord at $98.50. A radio test panel for jobbers and dealers has been announced by the Jewell Electrical Instrument Company. This new model No. 581 panel makes possible the