NEW PRODUCTS--Roundup of latest audio equipment and accessories.
Improved EPI Speaker System
The 1-inch inverted-dome tweeter and 8-inch woofer that have long been standard in EPI speaker systems have been improved in mass, mechanical tolerances, and power-handling capability for the new EPI Model 101.
The two-way system has a frequency response of 46 to 20,000 Hz and a nominal impedance of 8 ohms. The recommended range of amplifier powers for driving the sys tem is 12 to 75 watts per channel. High-frequency dispersion is said to maintain off-axis frequency response to within approximately 3 dB of on-axis response at 15,000 Hz. The sys tem measures 20 1/4 x 12 x 8 3/4 inches. It is finished in wood-grain vinyl with bronze met al trim surrounding the black foam grille. Price: about $120.
Pioneer's New Top-of-line Tuner
The TX-9500II has taken its place at the top of Pioneer's line of AM/FM stereo tuners.
Among its features are switchable i.f. band width (WIDE or NARROW) to provide a choice between maximum selectivity and maximum signal quality, a built-in test-tone oscillator to aid in setting tape-recording levels, and a choice of two degrees of FM interstation noise muting. Internally, the TX-9500II has a newly developed filter in its i.f. section that combines high effectiveness with phase linearity, plus a new 19-kHz pilot-signal "canceller" said to have much less effect on audio-frequency response than a conventional multiplex filter.
Usable sensitivity of the TX-9500II is 1.5 microvolts, with 50-dB quieting achieved at 2.5 microvolts in mono and 35 microvolts in stereo. Capture ratio (in the WIDE i.f. mode) is 0.8 dB, while alternate-channel selectivity is 35 dB in the WIDE mode and 85 dB in the NARROW mode. Other specifications, all for the WIDE mode, include AM suppression of 65 dB, 110-dB spurious-response rejection, and stereo, separation of 35 dB over the range of 50 to 15,000 Hz. Frequency response (stereo) is 20 to 15,000 Hz +0.2, -0.5 dB.
Distortion at mid-frequencies is 0.05 percent (mono) and 0.07 percent (stereo). The tuner has two pairs of output jacks, one set at a fixed level and the other variable by means of a front-panel control. A switchable circuit feeds multipath-signal products to the out puts, enabling the user to minimize them by means of antenna orientation. Approximate dimensions of the TX-9500II are 16 1/2 x 6 x 15 1/2 inches. Approximate price: $400, with an optional walnut cabinet costing $35. The next model in the Pioneer line, the TX-8500II, retains most of the features and much of the performance of the TX-9500, but at a price of about $275.
Superex Headphones: Low Price, Light Weight
The Superex TRL-77 is a non-acoustically isolating stereo headset weighing only 11 1/2 ounces (less cable). With its augmented low end, the TRL-77 has an overall frequency response of 25 to 20,000 Hz. The phones em ploy Mylar diaphragms within compact mold ed earpieces with user-replaceable foam cushions. The padded headband is a single piece of stainless steel.
With an impedance appropriate for the headphone jacks of virtually any receiver or integrated amplifier, the headset produces a sound-pressure level of 100 dB with an input of 5 milliwatts. For a mid-range signal at that level, distortion is 0.65 percent. The TRL-77's 7-foot cable terminates in a standard three-conductor phone plug. Suggested price: $30.
Elliptical Styli on Audio Technica's Latest Cartridges
To make its finest products available to consumers not requiring CD-4 playback, Audio-Technica is offering stereo equivalents of its highly ranked AT15Sa and AT12S phono cartridges with elliptical rather than Shibata styli. The new AT15XE ($100) has a 0.2 x 0.7-mil elliptical stylus, a frequency response of 5 to 30,000 Hz, and stereo separation of 28 dB at 1,000 Hz (23 dB at 10,000 Hz). The recommended range of tracking forces is 3/4 to 13/4 grams. Other specifications are identical to those of the AT15Sa, including the output of 2.7 millivolts for a recorded velocity of 5 centimeters per second.
The AT12XE ($60), an adaptation of the AT12S, has a 0.3 x 0.7-mil elliptical stylus and a tracking-force range of 1 to 14/4 grams. Frequency response is 15 to 28,000 Hz, and stereo separation is 24 dB at 1,000 Hz, 18 dB at 10,000 Hz.
Digital-readout Heathkit Receiver
The top of Heath Company's receiver line is now the AM/FM stereo AR-1515, equipped with a half-inch LED/digital display to indicate the tuned frequency. Power output is 70 watts per channel into 8 ohms on a continuous basis, with less than 0.08 percent harmonic or intermodulation distortion. The high-level in puts have a signal-to-noise ratio of 80 dB. The phono inputs, referred to a 2-millivolt input signal, have a 65-dB signal-to-noise ratio.
On FM the AR-1515 has a usable sensitivity of 1.8 microvolts, a capture ratio of 1.3 dB, and alternate-channel selectivity of 100 dB.
Image rejection is 90 dB, and AM suppression is 65 dB. The FM frequency response is 20 to 15,000 Hz ±1 dB.
Only the main controls-tuning, mode, in put selector, and volume-appear on the front panel. The rest are concealed behind a hinged trim section that flips down. These include main and remote speaker switching, balance, bass, and treble controls, FM interstation noise muting, high-frequency blend (for FM), tone-control defeat, high-frequency and sub sonic filters, and tape-monitor switching.
There is also a stereo headphone jack and tape-dubbing inputs and outputs augmenting those on the rear panel, plus a pushbutton for a Dolby decoder for Dolbyized FM broad casts that can be purchased optionally (in kit form) and installed by the user. The AR-1515 also has channel-center and signal-strength tuning meters as well as illuminated callouts for input selection and mode.
The Heathkit AR-1515 is available only in kit form. Approximate overall dimensions are 21 1/2 x 6 1/4 x 15 inches, including the decorative wood end pieces supplied. Price: $549.95.
The optional Dolby FM module costs $39.95.
Time-coherent Drivers in Ultraphase Speakers
The Ultraphase speaker systems, comprising a line of three models, all have their drivers mounted with voice coils in a straight perpendicular line to eliminate differences in arrival times (at the ear) of sounds emanating from the drivers.
The Ultraphase 5001 has a 12-inch woofer and an enclosure measuring 28 1/4 x 15 1/4 x 18 inches. The Model 3001 has a 10-inch woofer, the Model 2001 an 8-inch woofer. Their cabinet dimensions are 25 x 13 3/4 x 17 inches and 23 x 12 1/2 x 15 1/2 inches. Otherwise, the systems are all three-way designs with identical driver complements and specifications. Mid ranges are 2-inch domes and tweeters are 1-inch domes, with crossover frequencies of 550 and 4,500 Hz. Rear-panel controls adjust the outputs of the mid-range and high-frequency units. Minimum recommended amplifier power for all three systems is 20 watts per channel into their nominal 8-ohm impedances. Included in the prices of the speaker systems are black metal stands that support the enclosures at the bottom and rear, maintaining proper temporal alignment of the drivers for a seated listener. Prices: 5001, $390; 3001, $295; 2001, $190.
Audio Research's First Solid-state Components
After a long history of building only vacuum-tube amplifiers and preamplifiers, Audio Research Corporation has announced its first solid-state components, the SP-4 stereo preamplifier and D-100 stereo power amplifier. Much of the circuitry in both is based on the manufacturer's new "Analog Module," a sealed "gain block" that-in keeping with Audio Research philosophy-exhibits a mini mum of distortion even without negative feedback. In addition, the D-100 employs a total of thirty-two output transistors in two self-adjusting output stages.
The D-100 is rated at a continuous output (into 8 ohms) of 100 watts per channel from 1 to 20,000 Hz. Harmonic and intermodulation distortion are less than 0.1 and 0.05 percent, respectively, at any power level up to rated power. Signal-to-noise ratio exceeds 100 dB; nominal input impedance is 30,000 ohms. For an output of 2 volts rms into 100,000 ohms, the SP-4 has less than 0.005 percent harmonic or intermodulation distortion. Maximum out put is 10 volts into the same impedance. Signal-to-noise ratios are typically 95 dB for the high-level inputs and 84 dB for phono.
The SP-4 has knob controls for volume, balance, bass, and treble, and for mode and input selection. Switch-operated facilities include high-frequency filter, tone-control de feat, and tape-monitoring and dubbing facilities for two tape decks. The SP-4 has dimensions of 19 x 3 1/2 x 8 1/2 inches; the D-100 measures 19 x 5 1/4 x 10 1/4 inches and weighs 40 pounds.
Suggested prices: SP-4, $695; D-100, $895. Wood cabinets for both are optional, as is a "head amp" module for the SP-4 that will take the output of a moving-coil phono cartridge directly.
Conveyor Belt For Disc Dust
The Electroduster from the Audiotex division of GC Electronics takes a novel approach to record cleaning. A soft velour pad traverses the disc, removing dirt and dust particles. As debris accumulates, an endless, statically charged transparent belt, turned by the turntable platter itself, carries the dust off and deposits it onto a separate felt pad. The Electroduster has an adhesive base for easy installation on the motorboard. The main body of the device pivots upward to permit removal and replacement of records. The device also snaps off its base for complete removal. Price: $19.95, which includes replacement ve lour and felt pads,
New Guide to Imported Records
Euro-Disc Gazette is a bimonthly publication listing disc records from Europe that rep resent a high level of technical and musical interest. Reviews from the major English-language European magazines accompany the listings.
The Gazette also operates a mail-order service for subscribers. Any of the discs list ed can be ordered (before a specified bi monthly deadline) and received via fourth class mail within the four weeks following the deadline. Prices include all charges within the U.S. The Euro-Disc Gazette is available only to those with mailing addresses in the U.S. or Canada. Write the Gazette c/o Jim Callihan, Dept. SR, P.O. Box 337, Peterborough, N.H. 03458.
Braun's new Output C speaker system is described as a high-performance device small enough to fit the palm of one's hand. The diminutive, heavily damped aluminum enclosure contains a 4-inch air-suspension woofer and a 1-inch soft-dome tweeter along with a crossover network that divides the frequency range at 1,500 Hz. Frequency response is given as 50 to 25,000 Hz. The use of high-temperature materials results in a power-handling capability of 35 watts continuous into the system's nominal impedance of 4 ohms. Mini mum recommended amplifier power is 10 watts per channel. The enclosure is finished in black with a black perforated-metal grille. Dimensions are 6 3/4 x 4 1/4 x 4.5 inches. Price $100 each. The Output C is sold only in pairs.
Two Inexpensive Receivers from Sony
The Sony Models STR-3800 (shown) and STR-2800 AM/FM stereo receivers have respective power outputs of 25 and 20 watts per channel into 8 ohms, available on a continuous basis throughout the audio-frequency range with 0.5 percent harmonic distortion.
In operating features and appearance the two are very similar, providing controls for volume, balance, bass, and treble, switching be tween two pairs of speakers, signal-strength and channel-center tuning meters, and switchable loudness compensation and interstation noise muting on FM. Prices are also similar: $280 and $240, respectively.
FM specifications for the two receivers include a usable sensitivity of 2 microvolts, 50-dB quieting (in stereo) of 50 microvolts, a 1.5-dB capture ratio, 50-dB alternate-channel selectivity, and stereo separation of 35 dB at 1,000 Hz. Ultimate signal-to-noise ratio is 68 dB. The STR-3800 has tape-monitoring and dubbing facilities for two tape decks; the STR-2800 accepts a single deck. Dimensions for both receivers are approximately 19 x 5 3/4 x 13 inches, including wood end panels. A less expensive receiver, the STR-1800 ($180), pro vides 12 watts per channel into 8 ohms over a frequency range of 40 to 20,000 Hz, with less than 0.8 percent harmonic distortion.
The Dynaco SE-10, a stereo octave-band equalizer available as a kit or factory wired, has several features that enhance its versatility. Two sets of inputs and outputs are provided, switchable at the front panel, so that the unit can be set up to process either of two stereo signal paths-such as the front or the rear channels of a four-channel system, or the recording inputs or playback outputs of a tape machine-with no plugging or unplugging of cables. In addition, the SE-10 has the more usual tape-monitor jacks and switching plus an equalizer-defeat switch. The ten bands of each channel are governed by slider controls, as are the gains of each channel.
The Dynaco equalizer uses circuitry specifically designed for freedom from overload to achieve low distortion at large signal levels and extreme settings of the controls. The range of each control is ±12 dB at its center frequency. Frequency response with controls centered is 10 to 35,000 Hz ±1 dB. Hum and noise are 85 dB below a reference output of 2 volts. The input impedance is 50,000 ohms.
Harmonic and intermodulation distortion are a maximum of 0.04 and 0.02 percent, respectively. Dimensions: 13 1/2 x 4 1/4 x 11 3/4 inches. Price: kit, $249; factory wired, $349. The optional wood cabinet shown is $24.95.
The LTC speaker systems, which include the columnar LTC-100 (left), employ an unusual 10-inch woofer with a neoprene membrane covering 40 percent of the cone's effective radiating surface. The membrane is said to serve as an energy-control device that equalizes the upper end of the woofer's frequency range to match its lower end.
Besides the woofer, the LTC-100 employs four dome tweeters-two on the front behind a separate grille panel and one on either side of the enclosure. The output level from the side-mounted tweeters can be continuously varied independent of that from the front tweeters, which are also variable. The woofer-tweeter crossover frequency is 2,600 Hz.
In a normal listening environment the LTC-100's frequency response is rated at 36 to 24,000 Hz ±3 dB. The system has a nominal impedance of 8 ohms (6 ohms minimum), a power-handling capability of 100 watts continuous, and a minimum recommended amplifier-power rating of 20 watts continuous per channel. A resettable circuit breaker protects the drivers. Dimensions: 36 x 13 1/4 x 11 1/2 inches. Suggested price: $339.95. A similar system, but lacking the side-mounted tweeters, is the LTC-50 at $229.95.
NOTICE: All product descriptions and specifications quoted in these columns are based on materials sup plied by the manufacturer.
Recent fluctuations in the value of the dollar will have an effect on the price of merchandise imported into this country. Please be aware that the prices quoted in this issue may be subject to change.
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Also see:
ACOUSTIC RESEARCH -- AR14 speaker