Projection engineering (Jan-Dec 1931)

Page 26 PROJECTION ENGINEERING New Developments and News of the Industry W. H. HUTTER WITH CAPEHART CORPORATION Of interest to the trade is the announcement that W. H. Hutter, formerly chief engineer of the Webster Electric Company, Racine, Wisconsin, has become associated with The Capehart Corporation, Fort Wayne, Indiana. In his new connection with Capehart, Mr. Hutter is chief electrical engineer and in charge of manufacturer's division sales. He brings with him long experience in audio and acoustic research, and will concentrate on the more intensive development of tone quality for the Capehart line. For the past twenty-five years, Mr._ Hutter has specialized in audio and acoustics and during that time has served as consulting engineer in an advisory capacity to many companies engaged in radio production. _ His early training was with the American Telephone and Telegraph Company in the field of acoustics, audio research and publicaddress work. While with them he conducted and developed original design in electric pickup construction. PROJECTOR CARBONS Another important improvement in projector carbons is announced by National Carbon Company, Inc. This is the "precratering" of 9 mm. x 20-inch National high intensity projector carbons. Pre-cratering, as the name implies, consists in forming a crater at the burning tip of the carbon during the process of manufacture. In addition to the pre-cratered tip, the holder end of each carbon is beveled to permit easy insertion in the holder jaws. All 9 mm. x 20-inch high intensity carbons now leaving the factory embody these improvements. . • • 1 Pre-cratering gives better initial performance of the carbon in two respects. It results in clean burning when the arc is struck on a new carbon and it reduces the time required for the arc to burn in. Every projectionist will appreciate the importance of these features. PANEL MOUNTED AMPLIFIERS The General Amplifier Company. 27 Commercial Avenue, Cambridge, Massachusetts, announces a new line of panel amplifiers embracing several different types of rack mounting. This new line consists of microphone amplifiers, voltage amplifiers, and several types of output amplifiers, ranging in power output from 5 to 50 watts. These amplifiers are constructed on a quarter-inch steel panel finished in black crackle. They are of quality construction throughout, and very ruggedly made. They were primarily designed for the utmost in sound reproduction. NON-THEATRE SOUND INSTALLATIONS In addition to having broken all records for the sale of sound apparatus for theatre installations during the past sixty days, RCA Photophone, Inc., has increased its activities in the non-theatrical field to a marked degree. The largest single order for sound apparatus ever placed by the authorities of a state was received yesterday by Sydney E. Abel, general sales manager of RCA Photophone, Inc., from the depart ment of business control of the State of Washington. Four complete units of sound reproducing apparatus were ordered for the Washington State reformatory at Monroe ; the Washington State penitentiary at Walla Walla ; the Eastern State hospital at Medical Lake and the State training school at Chehalis. F. W. Normand, district manager of RCA Photophone at Seattle, negotiated the contracts. Mr. Abel said it was the intention of the Washington state authorities to install sound apparatus in every large state institution and that the contracts for the installation in the four institutions mentioned came after Messrs. 01sen and McKibben had seen and heard various types of apparatus demonstrated. LIGHT VALVE CONTROL The Enterprise Optical Mfg. Company, 564 West Randolph Street, Chicago, 111., for the Motiograph De Luxe Sound equipment employs an ingenious light valve control for the regulation of sound level. This is accomplished by controlling the amount of light falling on the light sensitive surface of the photocell. It is stated that by its use the fader device may be eliminated from the audio circuit. SOUND EQUIPMENT Jenkins and Adair, Inc., 3333 Belmont Avenue, Chicago, 111., have issued bulletin iE, illustrating a line of transformers, retards, gain controls, mixing controls and amplifier accessories. Bulletin 13 A describes a new monitor panel, and bulletin 14 A, a portable amplifier and portable mixer. NEW SOUND HEADS The Weber Machine Corpn., 59 Rutter St., Rochester, N. Y., announces a new synchrofilm unit for Motiograph de Luxe projectors. The illustration shows the drive. HOME TALKING PICTURES The Visionola Mfg. Corporation, 60 East 42d Street, New York, is having outstanding success in marketing the Visionola, a home talking picture outfit. The projection equipment, sound reproducer and screen all are mounted in one cabinet unit. NEW AMPLIFIER EQUIPMENT Five items of associated equipment especially designed for use with AmerTran series 80 power amplifiers have just been announced by the American Transformer Company, 178 Emmet Street, Newark, N. J. The new equipment is also arranged so that it may be used with other standard amplifiers having 500-ohm input circuits. The various units available are as follows : Master control, Type C-81 ; master control with one-stage pre-amplifier, Type A-88 ; two-stage, low-level input amplifier, Type A-89 ; "A" power supply unit (12-volt), Type P-78 ; and dynamic field supply unit, Type P-101. It is the function of master control Type C-81 to control volume, to select signals from a 500 or 200-ohm source, and to regulate operating current to the 200-ohm source. The volume control is a 500-ohm constant-impedance, T-pad attenuator and the output impedance is 500 ohms. The Type A-88 master control with pre-amplifier is identical to Type C-81 except a one-stage, low-level amplifier is connected in the 200ohm input circuit. Input amplifier Type A-89 is _ for raising low-level signals to values sufficient for exciting the main amplifier. It employs two transformer-coupled stages utilizing d-coperated 227-type tubes and has an output impedance of 500 ohms. It is available with a high-impedance or 500-ohm impedance input and is supplied in a compact metal case designed for wall mounting. Power supply unit Type P-78 has been designed to provide filament current for AmerTran d-c.-operated amplifiers, such as Type A-89. It has an output of 12 volts filtered d-c. at 1.75 amperes and operates from no-volt, 60-cycle lighting circuits. Power supply Type 101 is of similar design but provides an output of 7.5 or 15 volts at 1.5 amps. It will energize the fields of one or two dynamic loudspeakers. AMPLIFIER EQUIPMENT The Polymet Manufacturing Corpn., 829 East 134th Street, New York, has issued bulletin Amp-i illustrating and describing a new and up-to-date line of main and head amplifiers for sound installations. The company manufactures a standard line of condensers, resistors and chokes. The eauipment is being marketed in complete panels and in kits. "QUEEN" DIRECT-READING OHMMETERS An improvement over existing types ohmmeters with slide as rheostat of Wheatstqne bridge thereby giving uniform scale. Ratios 0.1, 1, 10, 100, 1000 and 10,000 with ranges from fraction of an ohm to 2,700,000 ohms. Operation consists only of closing keys and rotating scale index for balance. These are made by The Gray Instrument Co., 64 West Johnson St., Philadelphia, Pa.