Radio Broadcast (Nov. 1925-Apr 1926)

RADIO BROADCAST ADVERTISER 269 'Lighted Continuously 72 Days — and Still in Good Receiving Condition " AMPLIFIER AND DETECTOR, One astonishing report of the many hundreds received, proves unmistakably Sea Gulls' exceptionally long life. A user kept six Sea Gull Tubes lighted for oyer 1700 hours and found them all operating efficiently at the end of the period. The original letter containing the above statement is on file in our office and will be shown to any one interested. SEA GULL TUBES Have four points of superiority. 50% longer life, higher mutual conductance, uniformity, interchangeable at any stage, and they are positively non-microphonic. At Your Dealers $2-50 * or by mail plus parcel post. We also make Tube R-Rectifying Tube . . $3.00 Tube P— Semipower Tube . . $5.00 Tube X-Double Duty Rec. Tube $5 .00 Dealers and Jobbers write us for full information and discounts. Sea Gull Tubes give greater satisfaction ABERDEEN SPECIALTY CO., Inc. Factory 1640 N. Hutchinson Street, Philadelphia Main Sales Office Suite 406, 1001 Chestnut Street, Philadelphia This Amazing Test Proves Hbne Troubles Ended Exacting laboratory tests show that amazing new audio gives greatly superior tone curve. Remarkably uniform and even amplification of all tones at frequencies from 32 to 10,000 cycles Send Coupon PITCH ob FREQUENCY (. Note the smooth even progression of the Concert Grand curve, revealing supreme uniformity of amplification, from lowest notes to highest in the musical scale. ANEW audio frequency transformer has been perfected, the Erla Concert Grand. It is built on a new principle and gives results far superior to any other system of amplification. One-piece drtrwn steel shell provides magnetic shielding. Finished in black crystalline lacquer and attractive in appearance Amazing improvement Ordinary designs permit too much leakage to amplify properly at low frequencies. So we use the "quadriform type," heretofore unknown in radio work. In this design magnetic leakage is practically eliminated by providing twice as many paths for the magnetic field and by a better distribution of the core metal around the copper wire coils. Each of the four core units are complete magnetic circuits within themselves without breaks or joints to the main central core, and it will also be noticed that the central core section has a far greater area than conventional core types. The large area thus obtained reduces the effect of the direct "B" battery current on the pulsating voice currents and eliminates a cause of distortion common to Note the quadruple core surrounding the coil, forming an almost perfect path for the flux within the coil. The core is a special grade of laminated silicon steel that provides highest permeability and lowest hysteresis loss, with consequent maximum conductivity in the magnetic circuit of the transformer. Trice $10.00. West of Rocky Mts., $10.50. transformers using smaller core sections. The Concert Grand saves you money, too. Resistance coupling depends solely upon the tubes for amplification. Consequently they must be operated at maximum for efficiency, requiring more "A" battery current and higher plate voltage—135 to 150 volts. Filaments wear out more rapidly as result and battery life is more than cut in half. The higher initial cost of Concert Grand amplification is therefore saved many times over not only in improved performance but also in lowered upkeep cost. Booklet sent FREE Get the Audio Grand at your dealer's today. See what a tremendous difference it will make in your set. If you wish to return the coupon we will send you a new booklet giving the latest information on audio frequency amplification. ELECTRICAL RESEARCH Chicago, U. S. LABORATORIES A. ELECTRICAL RESEARCH LABORATORIES, 2500 Cottage Grove Ave., Dept. 10-C, Chicago. Send me information about the Erla Concert Grand Audio. Also latest developments on audio frequency amplification. Name Address City County. State. STATEMENT OF THE OWNERSHIP, MANAGEMENT, CIRCULATION, ETC., required by the Act of Congress of August 24, 1912, of RADIO BROADCAST, published monthly at Garden City, New York for October 1, 1925. State of New York, County of Nassau. Before me, a Notary Public in and for the State and County aforesaid, personally appeared S. A. Everitt, who, having been duly sworn according to law, deposes and says that he is the Treasurer of Doubleday, Page & Company, owners of Radio Broadcast and that the following is, to the best of his knowledge and belief, a true statement of the ownership, management (and if a daily paper, the circulation), etc., of the aforesaid publication for the date shown in the above caption, required by the Act of August 24, 1912, embodied in section 443, Postal Laws and Regulations, printed on the reverse of this form, to wit: 1. That the names and addresses of the publisher, editor, managing editor, and business managers are: Publisher, Doubleday, Page & Co., Garden City, N. Y.; Editor, Arthur H. Lynch, Garden City, N. Y.; Business Managers, Doubleday, Page & Co., Garden City, N. Y. 2. That the owner is: (If the publication is owned by an individual his name and address, or if owned by more than one individual the name and address of each, should be given below, if the publication is owned by a corporation the name of the corporation and the names and addresses of the stockholders owning or holding one per cent, or more of the total amount of stock should be given.) F. N. Doubleday, Garden City, N. Y.; Arthur W. Page, Garden City, N. Y.: S. A. Everitt, Garden City, N. Y.; Russell Doubleday, Garden City, N. Y.; Nelson Doubleday, Garden City, N. Y.; John J. Hessian, Garden City, N. Y.; Dorothy D. Babcock, Oyster Bay, N. Y.; Alice De Graff, Oyster Bay, N. Y.; Florence Van Wyck Doubleday, Oyster Bay, N. Y.; F. N. Doubleday, or Russell Doubleday, Trustee for Florence Van Wyck Doubleday, Garden City, N. Y.: Janet Doubleday, Glen Cove, N. Y.; W. Herbert Eaton, Garden City, N. Y.; W. F. Etherington, 50 E. 42nd St., N. Y. C. : S. A. Everitt or John J Hessian, Trustee for Josephine Everitt, Garden City, N. Y.; Henry L. Jones, 120 W. 32nd St., N. Y. C; Wm. J. Neal, Garden City, N. Y. ; Daniel W. Nye, Garden City, N. Y.: Mollie H. Page, Syosset, N. Y.; E. French Strother, Garden City, N. Y. 3. That the known bondholders, mortgagees, and other security holders owning or holding 1 per cent, or more of total amount of bonds, mortgages, or other securities are: (If there are none, so state.) NONE. 4. That the two paragraphs next above, giving the names of the owners, stockholders, and security hold •fa Tested and approved by Radio Broadcast -jfc ers, if any, contain not only the list of stockholders and security holders as they appear upon the books of the company but also, in cases where the stockholder or security holder appears upon the books of the company as trustee or in any other fiduciary relation, the name of the person or corporation for whom such trustee is acting, is given; also that the said two paragraphs contain statements embracing affiant's full knowledge and belief as to the circumstances and conditions under which stockholders and security holders who do not appear upon the books of the company as trustees, hold stock and securities in a capacity other than that of a bona fide owner; and this affiant has no reason to believe that any other person, association, or corporation has any interest direct or indirect in the said stock, bonds, or other securities than as so stated by him. 5. That the average number of copies of each issue of this publication sold or distributed, through the mails or otherwise, to paid subscribers during the six months preceding the date shown above is (This information is required from daily publications only.) (Signed) DOUBLEDAY, PAGE & COMPANY By S. A. Everitt, Treasurer. Sworn to and subscribed before me this 1st day of October, 1925. [seal] (Si-pted) Frank O' Sullivan (My commission expires March 30, 1926.)