NEC AVR-1000 A/V receiver Review

The NEC AVR-1000 surround-sound receiver is the first stereo receiver to carry the NEC brand name. It is also one of the most versatile audio/video (a/v) receivers we have seen to date, containing a high-quality am/fm stereo tuner, built-in surround-sound processing for both Dolby Surround and matrix systems, extensive audio and video program-selection capability, and four channels of amplification with a rated combined output of 300 watts. In addition, the AVR-1000 is furnished with a unified remote control that can be used to operate nearly every function of the receiver as well as a full system of compatible NEC components.

From the front, the AVR-1000 normally presents a knobless, uncomplicated appearance. A row of flat pushbuttons extends across the full width of the front panel. The buttons on the left switch the power on and off, select the AM or fm band and any of eighteen station frequencies (in two banks of nine), and tune in either direction. The ones on the right select the program source (phono, tuner, CD, tape, auxiliary, TV, or VCR), the surround-sound mode, one of three memorized volume/balance settings, and audio muting. A volume-reset button restores an initial comfortable listening level and center balance—a necessity because there is no visual indication of these settings.

The volume control is a flat rectangular plate in the lower right corner of the front panel. Next to it is the four-channel balance control, a square plate that shifts the balance in the direction corresponding to the side or corner of the plate that is pressed. The eight control axes are at 45-degree intervals. The balance adjustment is achieved by reducing the level from the direction opposite the one selected.

The upper portion of the front panel contains a number of displays showing the selected input source, the surround-system status, the tuned station frequency (including band and preset number), stereo reception, and correct tuning. In the center of the display panel is a multicolored SURROUND INDICATOR that shows the relative degree of activity in each of the four amplifier channels.

Pressing the upper right corner of a hinged door below the pushbutton controls reveals a number of less frequently used adjustments. Small knobs adjust the bass and treble— separately for the front and rear channels—and the individual gains of the left and right channels. Most of these controls affect the fm tuner’s operation, including automatic and manual scan tuning, preset memory storage, fm muting, and selection of mono or (automatic) stereo mode and wide or narrow if bandwidth.

A cryptically marked yellow vacation switch behind the hinged door is actually the main power switch for the receiver. It is normally left on at all times in order to keep the receiver’s memories “alive” and enable it to respond to a turn-on signal from the remote control. A small green led on the front panel glows to indicate that standby power is on.

The front channels of the NEC AVR-1000 are rated to deliver 100 watts per channel into 8-ohm loads, from 20 to 20,000 Hz, with no more than 0.02 percent total harmonic distortion. Unlike most receivers, it is also rated for driving 4-ohm loads, at 150 watts per channel, but with a distortion specification of 0.05 percent that applies only at 1,000 Hz. While it has a four-channel amplifier section, the rear (surround-sound) channels do not require as much power as the front channels, so the rear amplifier is rated at 50 watts per channel into 8 ohms, with no distortion or frequency range specified.

The rear apron of the receiver contains output connectors for the front and rear speaker pairs (there is no provision for driving additional speakers in other rooms) and two switched AC outlets. There are binding-post inputs for a 300-ohm fm antenna and the supplied am loop antenna, which clips onto the receiver. An F-type coaxial connector is furnished for a 75-ohm fm antenna. There is also a jack for connecting the AVR-1000 to an NEC K-700E cassette deck so that it can be controlled from the receiver’s remote unit.

The NEC AVR-1000, which is finished in black with white markings, measures 17 inches wide, 17 inches deep, and 5-1/2 inches high, and it weighs 35-1/2 pounds. Price: $869.

Lab Tests

Preconditioning the AVR-1000 by driving its front channels at one-third rated power for 1 hour (we did not drive the rear channels for the warm-up period) made the top of the cabinet only slightly warm, and it never became any hotter during our subsequent tests. The receiver showed its true mettle from the beginning, delivering 124 watts per channel at the clipping point into 8-ohm loads at 1,000 Hz. With 4-ohm loads, the clipping power was an impressive 190 watts per channel. Although the receiver is specifically not recommended for use with 2-ohm loads, we did try to drive 2 ohms (on one channel). Its protective relay shut it down at 68 watts, before any significant distortion was detected and, fortunately, before it suffered any damage.

Dynamic power measurements further underscored the power of this receiver. During a 20-millisecond tone burst, the front-channel output reached 156 watts into 8 ohms and 265 watts into 4 ohms. Even 2 ohms could be driven successfully with short program bursts, to a clipping level of 380 watts!

The front channels’ response was down 3 dB at 35,000 Hz, and they had a slew factor greater than 25. They were stable with reactive loads, and the protection system shut down the receiver when we drove it to high levels with 10,000-Hz square waves. We also measured the rear-channel amplifier, with equally satisfactory results. The 8-ohm output at clipping was 81 watts, rising to 121 watts with 4-ohm loads. The respective dynamic outputs were 100 and 180 watts. We tried 2-ohm operation in the dynamic tests too, obtaining a remarkable 264 watts from this nominally 50-watt amplifier section.

The distortion characteristics of the front and rear amplifiers were quite similar, both as a function of power and across the audio frequency spectrum. Our measurements slightly exceeded the specified values but were still entirely negligible, typically between 0.03 and 0.1 percent at 1,000 Hz for all power levels up to the rated maximum output. Similar results were obtained at rated power or less into 8- or 4-ohm loads from 20 to 20,000 Hz, with virtually no change in distortion from 20 to 5,000 Hz and a slight increase at 15,000 Hz.

The bass and treble tone controls had more than ample range, with little effect on the midrange level, and most of the effect took place near the adjustment limits of the small knobs. The basic response of the front channels, with the tone controls set at their center detents, was flat within 1.5 dB from 20 to 20.000 Hz. The rear channels were identical in the matrix mode, but, in accordance with Dolby specifications, in the Dolby Surround mode the highs were cut off sharply above 7.000 Hz and more gently at low frequencies, to — 6 dB at 20 Hz.

Through the CD input, the front channels required 15.5 millivolts for a reference output of 1 watt and had an A-weighted noise level of — 71.5 dB. Through the phono input, the sensitivity was 0.24 millivolt, and the noise level was —70.7 dB. The phono input overloaded at 135 to 150 millivolts from 20 to 1.000 Hz and at about 100 millivolts at 20,000 Hz. The RIAA equalization was very accurate, varying only +0.1, —0.6 dB from 20 to 20,000 Hz. The phono-input termination was 50,000 ohms in parallel with 165 picofarads of capacitance.

Like the amplifier section, the fm tuner of the AVR-1000 was better than we expected to find in a receiver. Its usable sensitivity and distortion were both good, though not unusual. The noise level, on the other hand, was unusually low, — 87 dB in mono and — 77 dB in stereo. The capture ratio of 1.25 dB, am rejection of 73 dB, and image rejection of 76 dB, while not record-setting, also set this receiver apart from most others we have tested.

All these measurements were made using the wide IF bandwidth, although spot checks showed that the narrow-band mode did not degrade the performance significantly. In the wide-band mode the alternate-channel selectivity was a very practical 41 dB, and in the narrowband mode it was a remarkable 85 dB. The fm stereo channel separation was among the most consistent we have seen. It measured 44.5 dB from 400 to 20,000 Hz and was still a very good 35 dB at 30 Hz. The frequency response of the am tuner section was +1, — 6 dB from 24 to 2,600 Hz.

Comments

We did not use the NEC AVR-1000 in an audio/video system, but we did use its matrix and Dolby Surround systems with various audio sources. Both did a fine job of enhancing the ambience of the reproduction, although their overall effects were somewhat different. The choice can be made on the basis of your personal preference with the particular program material.

Like any signal-processing system, surround sound can easily be used to excess. In our opinion, if the rear speakers can be heard as separate sources, they are too loud. But when the surround sound is scaled to the program material, the results can be very satisfying. Recordings of music from such films as Star Wars and its sequels, Star Trek, and others of similar character really benefit from surround-sound reproduction, and the AVR-1000 does at least as good a job in that respect as any receiver we have used.

The AVR-1000's performance as a two-channel receiver, however, is sufficient to justify its purchase for an audio-only system. The FM tuner section is truly excellent, and the amplifiers are, as our measurements show, genuine “powerhouses.” They are well protected, too, and suffered no ill effects from hard driving into clipping and other punishment. The AVR-1000 encouraged us to indulge in wall-rattling CD playback the likes of which we have rarely, if ever, enjoyed from a receiver.

The size and weight of the AVR-1000 are sufficient to keep it from becoming uncomfortably hot under any imaginable conditions of operation. Hours of high-level operation left the top cover, over the heat sinks, barely warmer than the ambient temperature. While we did not have the opportunity to use it with compatible NEC components, the remote control appears to pack every normal control function of all the possible components with which it might be used into a disarmingly simple and compact unit.

NEC has stepped off on the right foot with the introduction of its first stereo receiver. If the company extends the same design philosophy to more affordable receivers, it should have a clear impact on the audio market.

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