Radio Broadcast (May 1928-Apr 1929)

.RADIO BROADCAST ADVERTISER. XT CELOTEX baffle boards will not vibrate at any audible frequency or produce any resonant effects. Celotex will also prevent reflection of sound waves. 12 x 12 inches. . 18 x 18 inches. . 24 x 24 inches . . 36 x 36 inches . . $1.00 4 x 4 feet . . $7.50 . 2.00 6 x 3 feet 9.00 . 3.00 6 x 4 feet 12.00 . 4.50 8 x 4 feet 15.00 Holes cut according to specification At your jobbers or write to THE BAFFLE BOARD CO. 624 Madison Avenue New York, N. Y. Has Your Set "ADENOIDS"? It can be easily corrected. All it needs is an "adenoid" operation. Simply take out the trouble-causing inferior transformers and replace them with one of the AmerTran audio systems. It will make your old set as modern as any set regardless of price. See your dealer today AmeiOhan AMERICAN TRANSFORMER CO. 92 Emmet St. Newark, N. J. Transformer Manufacturers For More Than 29 Tears -Not an Extra & There is no choice. You must <<* <JT j^v use Amperite to automatically control variations in the "A" <?&t^&hP"-&* ' current supply to your tubes. NT A type for every tube A. C. or D. C. $1.10 with mounting (in U. S. A.) at all dealers. -^tk&ftiaU Gompany? Write Dept. RBi This symbol in a radio diagram means — FREE -"Amperite Blue Book" of modern circuits and valuable construction data • "SELF-ADJUSTING " Rheostat HELPFUL TECHNICAL INFORMATION A regular feature of Radio Broadcast is the series of Laboratory Information Sheets, which cover a wide range of information of immediate value to every radio worker, presented in a form making it easy to preserve them. To insure your having every issue, send your check for $4.00 for one year's subscription to Subscription Department Doubleday, Doran & Company, Inc. Garden City, N. Y. ROBERT S. KRUSE Consultant and Technical Writer 103 Meadowbrook Road, West Hartford, Conn. Telephone Hartford 45327 PLUG in a Falck Claroceptor between wall socket and radio set and eliminate "static'' from motors, street cars, telephones and electrical appliances. This new improvement by a pioneer radio parts manufacturer grounds and thus blocks out line interference noise and radio frequency disturbances. Also improves selectivity and distance. Requires no changes in set. Measures just 3^4 x Sl/2 x 2y2 inches. Thousands now all over America use the Claroceptor for clearer A. C. reception. Get one right away — at radio parts dealers. Write for descriptive folder. $7.50 complete with cord and plug CLAROCEPTOR Built by ADVANCE ELECTRIC CO. 1260 W. Sscond St. Los Angeles, Calif. JOBBERS and DEALERS, GET OUR PROPOSITION HOOK-UP WIRE The 5raid Slides Back* At All Dealers 25 Feet Stranded 35c 25 Feet Solid 30c Red, Green, Yellow, Blue, Black PDprp Send us the name and address of your dealer * "Eid anc] we w;[[ send you a sample package of Braidite FREE. Include ioc for postage. CORNISH WIRE CO. 38 Church Street New York City > 0 g P Q.QJ2JUL) . FOR every radio need, in brushed brass or Bakelite. Fit standard electrical switch or outlet box. Single plates and in gang in many combinations. No. 135— For Loud Speaker gl.OO No. 136— For Aerial and Ground 1.00 No. 137 — For Battery Connections 2.50 No. 138 — For A C Connections 1.00 (Bakelite, 25c additional per plate) At Your Jobber's YAXLEY MFG. CO. Dept. B, 9 So. Clinton St., Chicago, 111. Engineers that are competent now have a new big profitable field before them — We invite you to write us for information that will help you to capitalize on your experience and knowledge by installing — aMPLIOn Public Address Systems We have ready for quick installation group address equipment for both indoors and out for such places as Hotels, Theatres, Factories, Auditoriums, Clubs, Hospitals, Race Tracks, Railroad Depots, County Fairs, Summer Resorts, etc. Let our engineers help you make more money in this new field of amplification requiring special radio equipment. Briefly speaking we have established something new — A FREE Service Station for Radio Engineers and that is just what it is — a -well organized department of our business just to help you. We make no charge for this service it is freely given with Amplion's compliments and a background of 42 years of success in the acoustic field. We Have Ready For Immediate Delivery SPEAKERS 9" Cone Chassis (9^x9^4x7) ^1 5.50 14" Cone Chassis (24^x8^x19^) .. 16.50 16" Cone Chassis (26^x10x22) 17.00 UNITS— balanced armature (4x4x3) .... 8.00 A. C. 100 — Giant Dynamic Air Column Unit (weight 25 lbs.) (10x8x8) 150.00 Exciter for A. C. 100 unit (field current supply) (8x11x6) 30.00 STEP-DOWN TRANSFORMERS type .06 (5x6/2x7^) 20.00 type .07 (3x3x3J4) 10.00 HORNS 42" Trumpet (22" bell) (24x24x44).. 25.00 72" Trumpet (74x32x32) 56.00 10 ft. Air Column (60x37x46) 200.00 12Y2 ft. Column (34x48x33) 100.00 15 ft. Air Column (57x57x35) 250.00 MICROPHONE (9^x9^x7) 100.00 MICROPHONE TRANSFORMER (3x3x3^) 18.00 AMPLIFIERS 2 stage (210 tubes in P.P. in last stage) (17x14x9) 125.00 3 Stage (250 tubes in P.P. in last stage) (22x17x9) 175.00 MICROPHONE INPUT AMPLIFIER A. C. (14x15x9) 110.00 MICROPHONE INPUT AMPLIFIFR A. C. (15x17x9) 120.00 Amplion Cabinets for Moving Pictures Cabinets contain 2 turntable electric motors. Amplion electric pick-up and control board for fading one piece of music into another, or making instantaneous switches. P.M.S. 2 std. (30x40x46) $300.00 P.M.S. portable (12x32x22) 225.00 Phone Record Library 200 Record (14x14x30) £200.00 250 Record (14x14x30) 250.00 Especially designed for Non-Synchronous Moving Pictures. We furnish the complete installation or any part of the equipment as desired. Write for profitable Amplion proposition to competent Engineers AMPLION CORP. OF AMERICA 133 W. 21st. Street New York The Sign of Enduring Quality • april, 1929 . . . page 413 •