10 months ago

Electronics-World-1959-05 90 _AtirA146- TUBE PROBLEM: An amplifier manufacturer was plagued by noise, microphonics and hum that developed in the high gain stages of his amplifiers. Sonotone engineers were consulted on the problem. SONOTONE SOLVES IT: Sonotone engineers discovered that they could correct all three complaints by redesigning just one tube. RESULTS: The heater element was changed to a coil heater, eliminating the hum. And rigid controls on the mount structure and processing reduced microphonics and noise. This resulted in the Sonotone reliablt type 7025. It's now available for initial equipment and replacement purposes. Let Sonotone help solve your tube problem, too. $onotone. ELMSFORD, NEW YORK Leading makers ul tone ceramic cartridges, speakers, microphones, tape heads, electron tubes. In Canada. contact Atlas Radio Corp -, Ltd.. Toronto sequence. In addition, an "elevator action" changer spindle design preserves record centers and grooves by separating the bottom -most record from the stack to an interim position before its travel to the turntable. Detailed literature on the "Dual - 1006" is available on request. Address your letters to Desk 6 at the previously mentioned address. STEREOPHONES Koss Incorporated. 2227 North 31st St., Milwaukee 8, Wis. has just released its Model SP -3 "Stereophones" - - a specially constructed headset which permits the reception of two - channel sound with complete privacy. The headset covers the full frequency range of 30 to 15.000 cps by means of 3's -inch dynamic reproducers incorporated in each earphone. Since the "Stereophones" have an impedance of 4 ohms they can he connected directly across the amplifier's output or speaker's voice coil and thus no extra wiring within the amplifier is required. Adapters are also available for 600 - and 10.000 -ohm impedances, permitting the units to be used for monitoring purposes. The units come complete with 8 feet of cable and a plug. Local high -fidelity equipment dealers and electronic parts jobbers are handling this new item. ERIE CERAMIC CARTRIDGE Erie Technical Ceramic Dirision, State College, Penn. has just released a single- ceramic -element stereo cartridge which is the product of several years of development. The new unit offers a dynamically balanced single ceramic element in which both channel outputs are developed- making them inherently equal. Freedom from resonance peaks is obtained through oil damping. Marketed under the tradename "ST- ERIE-O," the new cartridge is available for immediate delivery. The Model 1304 cartridge has .7 mil diamond and 3 mil sapphire styli while the Model 1303 has dual sapphires. These models are supplied in kit form, including a 2 -foot length of shielded cable and necessary hardware for conversion. Separation is 20 db over the full audio frequency range. Response is 20 to 16,000 cps with output voltage .5 volt r.m.s. at 1000 cps. each channel. Compliance is 3 x 10 " cm /dyne, vertical and lateral. Recommended load is 2 megohms and recommended tracking pressure is 5 -6 grams. The unit is com- pletely compatible. Mounting dimensions are EIA standard ? t,;" and L.:" centers. Further details on these new cartridges are available from the firm's authorized distributors. EICO 14 -WATT AMPLIFIER Electronic Inst runic nt Co., Inc., 33 -00 Northern Blvd.. Long Island City 1, N. Y. has announced the availability of a 14 -watt high -fidelity power amplifier which has been designated as the HF -14. The new unit has a Williamson -type circuit and a push -pull EL84 output stage. A standard octal socket is provided for powering the HF65A and HF61A preamps. The unit is rated at 14 watts continuous, 28 watts peak. Frequency response is 15 to 100,000 cps ±.5 db at 1 watt and ±1.5 db from 15 to 125,000 cps. At 14 watts the response is 25 to 25,000 cps ±.5 db and ±1.5 db from 20 to 60,000 cps. Speaker connections are provided for 4 -, 8 -, or 16 -ohm voice- coils. The unit draws 65 watts at 117 volts a.c. The entire amplifier measures 3 "4 " x 12" x 4 ". It is available both in kit and factory wired versions. An enclosure (E -61 is available at extra cost. TAPE DECK HOUSINGS Viking of Minneapolis, Inc., 9600 Aldrich Avenue South, Minneapolis 20, Minn. has recently released two furniture cabinets for housing its 75 and 85 Series tape decks and related tape system components. The W3SX cabinet will accommodate either a 75 or 85 tape deck, together with a single recording amplifier or two playback preamps. Designed for table or shelf mounting, the enclosure can serve as a tape center for the music system. For the stereo system. the W4SX cabinet will house a 75 or 85 tape deck and two vertically mounted recording amplifiers. A bottom panel (below the ELECTRONICS WORLD

tape deck) is removable for custom installation of a power amplifier or mixer controls. Full details on these new units are included in the firm's accessory catalogue, Form 692, which is available from the manufacturer on request. G -E SPEAKER ENCLOSURE General Electric Company, West Genesee St., Auburn, N. Y. has announced the release of a new 5- cubic -foot "distributed port" 12 -inch speaker enclosure, the "Stereo Classic" EN -50. The enclosure is proportioned for minimum width and its height is compatible with the firm's EQ -1- series equipment cabinet. It has a recessed matching wood base and is available in mahogany, blonde oak, cherry, and walnut genuine wood veneer finishes. With a high -quality 12" coaxial or biaxial speaker, the EN -50 series has more than double the low- frequency power output capability (up to 4 db) of closed type enclosures, according to the company. Its response is clean down to 35 cycles. The enclosure features an optional front panel tweeter mount opening, with removable cover plate, for tweeters of 4- inches o.d. or less. The larger front panel opening accommodates all makes of 12" speakers. The seven "distributed port" openings are in the rear panel. Further information on this new series of enclosures is available from the company on request. MULTIPLE SPEAKER SWITCH Olson Radio Warehouse, 260 S. Forge St., Akron, Ohio has added the SW -130 multiple- speaker selector switch to its line of audio accessories. The new unit enables the user to connect and control up to six remote speakers without affecting impedance match at the sound source. The switch is designed for use with either 4- or B- ohm speakers. The device features simplified slide - type switches with six 4 -ohm, 2 -watt resistors and six 8 -ohm, 2 -watt resistors and easy -to- follow wiring instructions. The switches are mounted on a brushed brass panel suitable for custom mounting on hi -fi or p.a. control panels. The panel size is 3% "x2Ii ". "CROWN" STANDARDS UPPED International Radio & Electronics Corporation, Elkhart, Ind. has announced that guaranteed standards have been raised on its 1959 "Crown Stereo X" tape recorder. The new unit has two -track or four - track heads, is of all- aluminum construction, offers three speeds (15, 7',Z, 3% ips) has three motors and provides (Continued on page 94) May, 1959 Are you a recording engineer? "No, I'm a plumber ' .. but I know good recording tape" AUDIOTAPE, the thinking recordist's tape, gives you the full, rich reproduction so satisfying to the happy audiophile - be he doctor, lawyer or Indian chief. Because behind every reel of Audiotape are two decades of research and development in sound recording. When you buy a reel of Audiotape you're getting the tape that's the professionals' choice. Why ? For example, the machines that coat the oxides onto the base material are unique in this field - designed and built by Audio engineers who couldn't find commercial machines that met their rigid specifications. Then there's the C -slot reel - the fastest -threading reel ever developed. For that matter, there's the oxide itself - blended and combined with a special binder that eliminates oxide rub -off. There are many more reasons why the professionals insist on Audiotape. They know that there is only one quality of Audiotape. And this single top quality standard is maintained throughout each reel, and from reel to reel - for all eight types of Audiotape. That's what makes Audiotape the world's finest magnetic recording tape. For recording engineers, doctors, garbage men, investment brokers, sculptors ... and plumbers I Manufactured by AUDIO DEVICES, INC. 444 Madison Ave., New York 22, New York Offices in Hollywood & Chicago 1.Am A.A.. 91

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