Low-distortion Sansui Receiver Has Equalizer
The "Super-Feedforward" DC power-amplifier section in Sansui's Z-9000 microprocessor-controlled receiver is said to re duce all forms of steady-state and dynamic distortions. The unit is rated at 120 watts per channel from 5 to 100,000 Hz with total harmonic distortion of less than 0.005 percent. The preamplifier section includes a pre-preamp for moving-coil cartridges. Signal-to-noise ratio (S/N) of the moving-magnet phono section is 82 dB. The Z-9000 has a digital-synthesis tuner section with a S/N rated better than 80 dB. Usable sensitivity is better than 10.3 dBf, and distortion is under 0.05 percent. Sixteen presets are available ( eight AM, eight FM) as well as a choice of automatic or manual tuning and narrow or wide i.f. bandwidth.
The built-in graphic equalizer is a seven-band model with a reverberation amplifier and adjustable 0-to 3-second echo decay.
Other features include fluorescent peak-power meters, switching for three pairs of loudspeakers and two tape recorders, microphone mixing, a station-frequency display that doubles as a digital clock, and a three-memory program timer. Price: $950.
Two Low-impedance Stanton Cartridges
Stanton's new 885LZS (left) and 785LZE (right) low-impedance, low-output moving-magnet phono cartridges both in corporate a samarium-cobalt magnet attached to a specially developed cantilever whose material permits maximum stiffness with minimum moving mass. The 885LZS is designed for a tracking force of 3/4 to 1 1/2 grams and has a large-contact-area Stereohedron stylus. Output is 0.06 millivolt per cm/sec of recorded velocity. Frequency response extends from 20 to 40,000 Hz.
Channel separation is given as 35 dB, cartridge inductance as I millihenry, resistance as 3 ohms. The recommended load impedance is 100 ohms or higher. Designed to track at the same force as the 885LZS, the 785LZE has a 0.2 x 0.7-mil elliptical stylus and a 30-dB separation specification. Both cartridges weigh 5.5 grams, come with a Stanton long-hair record brush, and have user-replaceable styli. Prices: 885LZS, $150; 785LZE, $100.
LaserDisc Player Has CX Decoding
Pioneer Video's top-of-the-line LD-1100 laser-optical videodisc player includes a CX noise-reduction / dynamic-range-expansion system for use with CX-encoded videodiscs. Properly decoded, such discs are said to offer an audio signal-to-noise ratio greater than 70 dB and a frequency-response range of 40 to 20,000 Hz. The LD-1100 comes with a handheld infrared remote-control unit for audio switching, random access to individual videodisc chapters or frames, scanning, fast forward or reverse at three times normal speed, slow motion, and step- and freeze-frame display. It also has pause and play controls and a reject switch for changing videodiscs. The front panel of the player duplicates most of the controls on the remote unit. It also has the power switch, a CX on/off switch, and a variable-speed control for the slow-motion mode. Audio-output connections are made with stereo phono jacks on the rear panel. Both r.f. and NTSC video outputs are provided. Dimensions are 20 3/8 x 5 5/8 x 15 3/4 inches. Price: $800. Pioneer Video, Inc., Dept. SR, 200 West Grand Avenue, Montvale, N.J. 07645.
Yamaha's Low-profile Turntable Line
Yamaha's new P-200, P-300, P-500, and P-700 turntables all feature low-profile styling, smoked-plastic dust covers, and improved versions of Yamaha's "Optimum Mass, Minimum Resonance" straight tone arm. The tone arm has been simplified and modified for a damped resonance frequency designed to fall near 12 Hz with most phono cartridges.
The P-200 is a belt-drive semi-automatic unit, the P-300 a direct-drive semi-automatic model, and the P-500 a direct-drive fully automatic turntable. The P-700 (shown) has a quartz-regulated-PLL direct-drive mechanism, fully automatic operation, light-touch front-panel controls, and two lightweight headshells. Wow-and-flutter is given as 0.015 percent (wrms); signal-to-noise ratio is 78 dB. Weight is 13 1/4 pounds. Dimensions of all four new models are 17 1/4 x 4 3/8 x 14 7/8 inches. Prices: P-200, $150; P-300, $190; P-500, $220; P 700, $270.
Computer Controls JVC's Top Tuner
The T-X55 quartz-locked digital-synthesis AM/FM stereo tuner from JVC features automatic computer-controlled optimization of reception and newly developed circuitry for improved performance. When tuning in a station, the built-in microcomputer measures the signal strengths of the desired station and of adjacent stations that might interfere with reception. It then adjusts antenna attenuators, i.f. bandwidth, and stereo blend for best reception. The circuitry includes a gallium-arsenide field effect-transistor (FET) mixer for reduced station cross-modulation, a high-Q varicap in the front end for improved selectivity, a non-multiplexed drive of the front-panel display for lower noise, and a new quadrature detector and balanced AM mixer.
Other features of the T-X55 include eight FM and eight AM station presets, an AM sensitivity switch for improved AM reception, a recording calibration-tone switch, manual override of the computer-set parameters, a digital r.f. field-strength display (which doubles as the station-frequency indicator), a six-broadcast programmable-timer recording function that makes possible the sequential recording of different stations, and a detachable AM loop antenna. FM specifications include a mono usable sensitivity of 10.3 dBf (0.9 microvolt, or µV) and a 50-dB-quieting sensitivity of 31 dBf (9.8 µV) in stereo. The A-weighted stereo signal-to-noise ratio with short-circuited antenna terminals is 80 dB. At 1,000 Hz, total harmonic distortion in stereo is 0.07 percent. Alternate-channel selectivity and image-response ratio are both 80 dB.
Capture ratio is 1 dB and stereo separation at 1,000 Hz is 50 dB. Frequency response is given as 30 to 15,000 Hz +0.3,-0.8 dB. In AM, usable sensitivity is 20 µV with an external antenna, total harmonic distortion is 0.3 percent, and signal-to-noise ratio is 50 dB. Dimensions are 17 1/8 x 3 x 12 1/2 inches; weight is 7 pounds. Price: $350.
Bass-reflex Speakers From Denmark's Jamo
Jamo Hi-Fi's CBR (Center Bass Reflex) speaker systems incorporate special features intended to eliminate secondary resonances transferred to the speaker's front plate by drivers and enclosure components. A claimed 10-dB reduction of these resonances is achieved in CBR speakers by a combination of compliant woofer mounting and a port that loads the woofer sym metrically to minimize distortion. The bowed fronts are said to insure correct phase relationships of the drivers.
There are five models in the series. The top-of-the-line CBR 1702 (shown without grille cloth) is a four-way system with a 13-inch woofer, 7- and 2-inch polypropylene-dome midrange drivers, and a 1-inch dome tweeter. A 12-watt input will produce a 96-dB sound-pressure level at 1 meter. Frequency response is given as 22 to 22,000 Hz; impedance ranges down to 4 ohms.
There are level controls for the midranges and tweeter. Enclosure dimensions are 32 x 17 x 14 inches, and a pedestal support is supplied. Price: $649.95. Jamo Hi-Fi U.S.A., Inc., Dept. SR, 916 Ash Street, Winnetka, Ill. 60093.
Audiosource's Budget-priced Equalizer / Analyzer
The EQ-One combination real-time analyzer, ten-band graphic equalizer, and pink-noise generator from Audiosource combines three useful components in a single rack-mountable chassis. The ninety two-LED analyzer display can be used along with the pink-noise generator and equalizer to perform speaker/listening room equalization and optimization of speaker placement besides showing the frequency content of audio signals. The analyzer can be switched to either a 16- or 32-dB display range. The equalizer has center frequencies of 31.5, 63, 125, 250, 500, 1,000, 2,000, 4,000, 8,000, and 16,000 Hz for each channel. The control range is ±12 dB, the control bandwidth ("Q") 2.5. The unit can be switched to equalize tape recordings during recording or playback.
A switchable infrasonic filter provides an 18-dB-per-octave rolloff starting at 20 Hz.
Frequency response is 3 to 100,000 Hz ± 0.75 dB with all controls centered. Distortion is 0.2 percent or better from 20 to 50,000 Hz. An electret-condenser micro phone with a frequency response of 30 to 16,000 Hz is supplied for room and speaker equalization. Dimensions of the EQ-One are 19 x 5 1/4 x 8 3/8 inches; weight is about 8 1/2 pounds. Price: $399.95. Audiosource, Dept. SR, 1185 Chess Drive, Foster City, Calif. 94404.
JBL's Four-way, Floor-standing Speaker System
The enclosure of the JBL L250 is an asymmetrical pyramid, a shape chosen for its acoustical properties. The front-panel width varies according to each driver's size, all edges are rounded to minimize diffraction effects, the dome tweeter is positioned at the best height for average listeners, and the front baffle is slanted so as to align the drivers' acoustical centers. All units are sold in mirror-image pairs for better imaging.
The L250's crossover frequencies are 400, 1,600, and 4,500 Hz, and there are shelving controls for the lower and upper midrange drivers (three settings) and a roll-off control for the high-frequency driver (four settings). Adjustments are made with high-current stepped attenuators; the cross over network's components were selected to meet the demands of high-power operation.
The widths and crossover points of the drivers-a vented 14-inch low-frequency, an 8-inch lower-midrange, a 5-inch upper-mid range, and a 1-inch soft-dome high-frequency-were chosen for consistent, wide dispersion and smooth, wide-range response. The midrange units are housed in isolated sub-chambers to prevent acoustical interactions with the other drivers. Sensitivity is 90 dB sound-pressure level at 1 meter with a 1-watt input. Nominal impedance is 8 ohms; maximum power-handling capability is 400 watts.
Dimensions are 52 x 22 1/2 x 14 1/4 inches; weight is 135 pounds. Standard finish is oiled American black walnut, but black painted birch, Makassar ebony, Indian rosewood, and white-oak finishes are avail able by special order. Choices for grille-cloth color include black, blue, brown, maroon, rust, and tan. Price: $1,200 to $1,800 per unit depending on finish.
Akai's Top-of-the-line Cassette Deck
The microcomputer-controlled Akai GX-F9 1 cassette deck is a three-head, two-motor unit with a quartz-locked direct-drive dual-capstan closed-loop tape transport.
The microcomputer automatically sets optimal equalization, sensitivity, and bias levels for any tape type, with fine-tuning in a series of sixty-four 0.26-dB steps. (There is also a manual fine-tuning bias control.) The system's memories will store up to four tape settings. The deck incorporates Akai's Su per GX crystal-ferrite heads, which are said to be guaranteed for more than seventeen years of use (150,000 hours). The fluorescent twenty-four-segment meters show peak or VU levels. The "Instant Program Location System" locates the beginnings of pro gram segments, and the "Intro Scan" function plays back the first 10 seconds of each selection.
Specifications include a frequency response of 20 to 21,000 Hz ±3 dB (metal tape,-20-VU recording level). Response with ferric tape extends to 18,000 Hz. Signal-to-noise ratio with metal tape is greater than 60 dB; this figure improves by 10 dB above 5 kHz with the Dolby-B circuits on and by 20 dB from 1 to 10 kHz with the Dolby-C circuits operating. Wow-and-flutter is less than 0.025 percent (wrms) or 0.08 percent (DIN). Tape-speed tolerance is ±1 percent. Dimensions are 17 1/4 x 14 1/4 inches. Price: $750.
Denon Preamp Has Class-A Circuitry
Denon's PRA-6000 preamplifier features class-A non-feedback circuitry throughout, which the manufacturer claims eliminates dynamic and transient intermodulation distortions. The phono-preamp section deviates from the RIAA standard by no more than ±0.2 dB from 10 to 100,000 Hz. The unit's passive tone controls include a five-position switch that varies the high- and low-frequency turnover frequencies simultaneously. Other features include three phono inputs (two of which can be set for either moving-magnet or moving-coil cartridges), a high-level input for digital audio discs, connections and switching for two tape recorders, and switchable infra sonic-filter frequency and rolloff rate. The signal-to-noise ratio (A-weighted) of the moving-magnet phono preamp is 87 dB. Distortion of the high-level circuitry is given as less than 0.002 percent from 20 to 20,000 Hz. High-level channel separation is 100 dB. Dimensions are 18 x 5 1/4 x 15 1/2 inches; weight is 31 1/2 pounds. Price: $3,000.
The ARIMS from Acoustic Research is a miniature two-way acoustic-suspension speaker housed in a rigid drawn-aluminum cabinet. Threaded inserts on the rear of the cabinet accommodate several mounting options (wall, ceiling, etc.). The driver complement includes a 4-inch woofer and a 3/4-inch liquid-cooled dome tweeter. Cross over frequency is 2,800 Hz; slopes are 12 dB per octave. Rated sensitivity is 88 dB sound-pressure level at 1 meter with a 2.83-volt input. Nominal impedance is 4 ohms with a 3.8-ohm minimum. Recommended amplifier power is 7 watts minimum; power-handling capability is 75 watts per channel with normal program material. The ARIMS's half-power (-3-dB) points are 95 and 25,000 Hz.
Dimensions are 7 1/4 x 4 3/4 x 4 3/4 inches; weight is 4 1/2 pounds. The finish is scratch-resistant textured grey aluminum with a black perforated aluminum grille. Price: $220 per pair.
Digital-synthesis Sony Receivers
Two of Sony's newest receivers, the STR-VX33 (shown) and STR-VX22, feature "Direct Access" tuning in which the user can enter the station frequency directly. If the exact station frequency is not known, the user can enter the approximate frequency and use the scanning controls to find the desired station. Up to eight AM or FM stations can be preset. The STR-VX33 also has a "Memory Scan" function that samples each preset station for about four seconds. New low-noise integrated circuits are used in the i.f. and multiplex stages of the tuner sections of both receiver models.
The units have bass, treble, and loudness controls as well as connections and switching for two pairs of speakers. The STR VX33 can handle two tape decks, the STR VX22 only one. The auxiliary inputs are also labeled DAD (for digital-audio discs).
The STR-VX33 is rated to deliver 40 watts per channel into 8-ohm loads with no more than 0.008 percent total harmonic distortion; the STR-VX22 at 30 W/ch has no more than 0.03 percent THD. Prices: STR VX33, $310; STR-VX22, $250.
Acoustic-isolation Products from Mission Electronics
Two new products from Mission Electronics, the Mission Sorbomat and the Isoplat, are designed to cut down on unwanted vibrations in a turntable system. Both are made with a polyurethane elastomer called Sorbothane that is described as a "quasi-liquid molecular spring" with both the dimensional stability of a solid and many of the hydraulic characteristics of a fluid. Sorbothane is claimed to absorb much of the energy impinging on it, thus making it suit able for turntable isolation.
The Mission Sorbomat is a 12-inch-diameter, 3-millimeter-thick pad that replaces the mat supplied with most turntables. It is designed to keep rumble, motor vibrations, bearing noise, and platter ringing from reaching the cartridge. Airborne acoustical vibrations are also said to be absorbed and damped by the mat.
The Isoplat (photo) is said to keep vibrations and resonances from reaching any equipment placed on it. The 17 1/4 x 14-inch platform is supported on feet made of Sorbothane. The manufacturer says that most components, but especially turntables, can benefit from the Isoplat's isolation from many complex and reinforcing vibrations transmitted through floors, shelves, and cabinetry. Prices: Sorbomat, $39; Isoplat, $59. Mission Electronics, Dept. SR, 310 Carlingview Drive, Rexdale, Ontario, Canada, M9W 5G1.
Fuji Cassettes Have Improved Tapes, New Shell Design
Improvements have been announced in the magnetic coatings, tape binders, and mechanical construction of Fuji's audio cassettes. New manufacturing processes applied to the tapes include "Mono Particle Dispersion" (preventing clusters of magnetic particles) and "Micro Integrated Orientation" (thoroughly aligning the particles parallel to the recording tracks), both of which are said to result in increased output level and lower bias-noise levels. The new binder formulation provides improved cohesiveness and resilience plus increased immunity to temperature and humidity effects. The new cassette shells have loop-prevention guides to eliminate tape snagging and tension-stabilizer guides to minimize irregularities in tape run. All the cassettes in the line have cleaning leader tape and extra cassette labels, and all except the DR cassettes have a Braille side indication.
There are five types of cassette in the new line: FM Metal (a metal-bias tape), FR-II (a premium CrO2 equivalent tape), FR-I (a super-premium ferric-bias tape), ER (a premium ferric tape), and DR (a low-noise, high-output ferric tape). All are available in C-46, C-60, and C-90 lengths; C-120 DR cassettes are also available. Prices for C-90s: FR Metal, $10.75; FR-II, $7.50; FR-I, $7.50; ER, $5.75; DR, $4.75.
Medium-power Integrated-amp Kit From Heath
The Heathkit AA-1205 integrated amplifier is rated at 30 watts per channel into 8-ohm loads with less than 0.009 percent total harmonic distortion. The power-amplifier section is a class-AB design with a dynamically biased output stage for low distortion. The preamplifier section has inputs for tuner, two phono cartridges, two tape decks, and two auxiliary sources. An adaptor loop allows insertion of an equalizer, audio processor, or other accessory into the system. A peak-reading, ten-LED bar-graph display for each channel indicates output levels over a 45-dB dynamic range.
The front panel also has switches to activate 20- or 50-Hz low-frequency filters and 6- or 12-kHz high-frequency filters, change the tone-control turnover points, and defeat the tone controls. The back panel has preamp-out and power-amp-in jacks to permit substituting other amplifiers or adding crossovers or equalizers. Size is 4 1/4 x 17 x 13 inches. Price: $289.95.
Pyramid Loudspeaker's Modular System
The three-part "Futuresonics" system from Pyramid Loudspeaker consists of the Metronome 7 full-range minispeaker, the Metronome 8W bass module, and the T-9 high-frequency ribbon speaker. The three modules can be combined in various ways, either physically separated or stacked as the photo shows, to form a customized sound system. Using one or two Met 8W units with a pair of Met 7s provides ex tended bass response, and the addition of a pair of T-9 modules is said to improve mid and high-frequency response and spatial imaging. An optional concealing grille cover (in black or wheat color) and bracket kit are available for installations combining the three modules into a single floor-standing system measuring 45 x 16 3/4 x 13 inches.
Frequency response of the Met 7 is given as 76 to 22,000 Hz ±3 dB. The Met 8W is rated at 30 to 150 or 30 to 250 Hz ±3 dB depending on the setting of the internal crossover. The bipolar-radiating T-9 has a rated response of 4,000 to 40,000 Hz ±3 dB and includes a sensitivity selector. The complete three-piece Futuresonics system is rated for a response of 30 to 40,000 Hz ± 3 dB. Available finishes for the bass module are oak or walnut; the Met 7 is finished in black or simulated-walnut vinyl, the T-9 in walnut veneer. Total system price: $1,718 (East Coast). Pyramid Loudspeaker Corp., Dept. SR, P.O. Box 192, Flushing, N.Y. 11352.
New Top-of-the-line Radio Shack Speaker---The Realistic Optimus T-300 floor-standing speaker from Radio Shack has a rated frequency response of 44 to 20,000 Hz, sensitivity of 91 dB sound-pressure level at 1 meter, and power-handling capability of 150 watts. The drivers are a 10-inch long-throw woofer, 10-inch passive radiator, 5-inch midrange, and 1-inch ferrofluid cooled soft-dome tweeter. Two L-pads ad just midrange and tweeters to suit room acoustics. System impedance is 8 ohms. The design of the front baffle and grille is said to minimize diffraction effects and to enhance dispersion at high frequencies. Finish is genuine oiled-walnut veneer. Dimensions are 34 x 12 5/8 x 14 inches. Price: $259.95.
Also see:
NEW AUDIO PRODUCTS AT CES '81, PART 2: A report on accessories and audio/video developments.
Source: Stereo Review (USA magazine)