The Sensible Audiophile's Receiver
Nikko NR-819 amplifier section
Nikko NR-819 tuner section
MONO FM FREQUENCY RESPONSE
Nikko NR-819 stereo FM/AM receiver in metal case with wood end panels.
Dimensions: 19 18 by 6 3/16 inches (front panel), 11 inches deep plus clearance for controls and connections. AC convenience outlets: 1 switched (100 watts max.), 1 unswitched (200 watts max.). Price: $369.95.
Warranty: "limited," three years parts and labor; repair-estimate service on non-warranty repairs. Manufacturer: Nikko Electric, Japan; U.S. distributor: Nikko Electric Corp. of America, 16270 Raymer St., Van Nuys, Ca. 91406.
The American audiophile thinks of Nikko as a high fidelity manufacturer with a reputation for lots of features at a modest price. That reputation has been somewhat obscured in the last few years by Nikko's forays into high-performance separates, but the NR-819 receiver returns to tradition with 45 watts (16 1/2 dBw) per channel and T-Locked tuning.
The last is yet another name for the modern version of automatic frequency control: The receiver senses the frequency of the station it is receiving and aligns itself for (presumably) best reception. As exemplified in this model, the system works well; distortion--the best indicator of proper tuning-is low in both the stereo and mono modes. This is fortunate, since the T-Lock cannot be defeated on the NR-8 19. As soon as your hand moves away from the tuning knob, T-Lock takes control.
Midband quieting sensitivity is good and proves even better at the low end of the dial; at the upper end, however, sensitivity drops off noticeably both on the DSL bench and in the listening room. Tne very respectable ultimate (65-dBf signal-to-noise ratios differ by only 3 dB between the two modes. Calibration of the tuning dial is sufficiently accurate (closer than 0. 1 MHz) to allow you to identify the station you're hearing, not all that common an attribute in moderate-priced receivers. Adjacent-channel selectivity is good (5 1/2 dB, measured for stations 200 kHz apart), but the more common alternate-channel measurement (for stations 400 kHz apart) does not compare as favorably with other tuners. In our fairly crowded listening area, however, we find few signs of alternate-channel interference. Capture ratio is about average. At an input of 45 dBf-the standard test level-AM suppression is excellent, but DSL noted that the suppression was less (by 10 or 11 dB) at 35 and 65 dBf. Though the stereo subcarrier is well suppressed, a relatively substantial amount of 19-kHz pilot appears in the output; use of a multiplex filter when taping off the Nikko's FM section would be a hedge against Dolby mistracking. Frequency response is almost as flat in stereo as in mono; channel separation is entirely adequate.
The muting and stereo thresholds are identical, and each exhibits a healthy amount of "hysteresis"--the difference in signal level between the point at which the receiver un-mutes (or switches to stereo) and the point at which it mutes (or reverts to mono). The NR-819 does not come out of mute until input reaches 29 1/2 dBf-and mono S/N ratio is better than 64 dB. Once active, however, it stays with the station down to 20 1/2 dBf (for a S/N of about 56 dB). Thus the receiver is unusually free of sonic "flicker" in the presence of a fading signal, including multipath caused by passing airplanes. We consider this an excellent idea; in the listening room, we never experienced instability on fading stations. (In the data, we report the muting and stereo thresholds as the average of the "on" and "off" levels.) The Nikko NR-819 easily meets its power rating, and the dynamic headroom of 1 1/2 dB suggests a music capability of about 62 watts per channel. As usual, extra power is available with 4-ohm loads. The generally negligible harmonic distortion consists predominantly of the "soft" second-order type with traces of fourth near the band edges. At rated output, the measurements generally fall below an insignificant 0.02%; at 0 dBW (1 watt), they inch past 0.05% only at 20 kHz and remain near 0.01 % throughout most of the frequency range. With the tone controls set at their center detents, response droops a bit at both ends of the audio band, but the important frequencies are within a'/-dB tolerance. The fixed-turnover controls themselves shelve at ± 10 dB, with relatively modest boost or cut at the first two positions on either side of center, for somewhat finer resolution than is typical. The LOUDNESS boosts both bass and treble with a 1 3-dB low-frequency shelf and continually rising highs to about +9 dB at 20 kHz. Beyond the one o'clock position of the volume control-which has forty-one detents-"flat" response is restored.
Phono equalization-which is measured through. and therefore reflects the response of, the amplifier section-is down I y. dB at 20 Hz. By the time the 5-Hz warp region is reached, the phono preamp offers a 91/2rdB rejection. This can be improved further with the infrasonic filter. The high-cut filter affords the same (6 dB per octave) gentle slope and an 1 1-kHz cutoff frequency, making its effect on both signal and noise minor. The phone) preamp combines low residual noise with more than adequate headroom and provides a good load for a fixed-coil cartridge. Tape-output levels are appropriate from all sources, and isolation resistors reduce the probability that a deck may introduce distortion into the main signal path. The tape-output impedance is reasonably low when dubbing from a disc but considerably higher from the tuner, which still should present no problem provided that the interconnecting cables to the recorder are no more than 10 feet long.
All in all, Nikko has balanced performance, features, and price quite nicely in the NR-8 19. Provision for only one tape deck is quite common in this price range; those with a penchant for dubbing or multiple tape formats can add an outboard deck-switching box at moderate cost. We're impressed that Nikko has forsworn glitter for its own sake and has put the design costs where they belong-into performance and sensible features. Specifically, though there are no output-power meters or flashing LED displays, there are conventional signal-strength and tuning meters and an accurate, useful tuning lock. While we would prefer better low-signal sensitivity from the signal-strength meter (it requires about 30 dBf of antenna input for a visible deflection), it is nonetheless more useful than most of the five-LED indicators now in vogue. The FM mute and stereo threshold are especially stable, and sensitivity is adequate for most areas over most of the band. The reception is notably clean and quiet and quite free of interference. The phono preamp elicits excellent response from the cartridge we used, with a bright, almost bell-like clarity, and is as quiet as one could ask. The Nikko NR-819 is a receiver for sensible audiophiles.
(High Fidelity, Oct. 1979)
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