Luxman RV-371 AV-receiver
As Luxman's newest and most advanced audio/video (A/V) receiver, the RV-371 contains, among other things, a high-quality AM/FM tuner, signal switching for a number of audio and video sources, Dolby Pro Logic surround decoder circuitry, four simuiated-hall ambience-enhancement modes with adjustable surround-channel delay, and five power-amplifier channels.
The RV-371 can also serve as the master control station for a number of multiroom remote-control facilities. Through its System Bus, Deck Control, and Serial Out jacks, the receiver can control various compatible Luxman tape decks and CD players. Via a Luxman RC-505 in-wall keypad, the RV-371 and its associated signal sources can also be operated from other rooms, with full remote access to their major operating controls and functions. In addition, remote-control sensor inputs enable the receiver to be fully operated using its own wireless remote control, even from another room.
The RV-371's front panel, though well populated with buttons and knobs, is not as daunting or confusing as those of most A/V receivers we have seen. Large rectangular buttons switch the receiver between standby and operating modes and select its input sources, which include tuner, auxiliary, CD, phono, TV, laserdisc (LD), two VCR's, and two other audio/video sources designated AV-1 and AV-2. Although all signal connectors are accessible on the rear apron, a second set of AV-2 inputs on the front panel, selected by a nearby button, simplifies operation with a VCR or camcorder that is not regularly part of the system. All video inputs as well as the video-monitor output accommodate both S-video and composite-video signals.
Signal connections for two audio tape decks, designated Tape/DAT 1 and Tape/DAT 2, are selected by smaller buttons below the main input selectors. Recording sources are selected separately for the audio and video portions of the signal by means of two knobs in a row of infrequently used controls along the bottom of the panel. The audio record-out knob connects the audio signal from any input source to the recording jacks on the rear apron of the receiver. Another knob channels any of the video sources to the VCR record-out jacks. A Synchro button between the recording selectors can start a compatible Luxman CD player and tape deck simultaneously for convenient dubbing.
Also along the lower portion of the panel are a stereo headphone jack, the AV-2 input jacks, center-detented bass and treble tone-control knobs with a pushbutton tone-bypass switch, and a center-detented balance control. Small buttons activate the "subsonic" (infrasonic) filter and loudness-compensation circuits.
The display window on the panel shows the tuner frequency and operating mode, preset-station channel number, and relative signal strength. A two-digit display in the window shows the surround-channel delay in milliseconds or the relative level in decibels of the surround-channel outputs. Small red LED's show the selected input source and the signal level applied to the surround circuits. The large volume knob, motor-driven when operated from the remote control, also carries a red LED index light so that you can see its setting from across the room.
A group of small buttons below the display window controls the tuner section's operation, including band selection (AM or FM), stereo/mono switching, auto-seek mode, and manual up/down tuning. The FM tuning intervals can be set by a switch on the back of the receiver, either to the normal 200-kHz channel steps or to the 25-kHz steps required by some cable-distribution systems. Above the tuning controls are eleven small buttons for storing and recalling up to twenty preset tuner channels (AM or FM).
There are other inconspicuous controls across the width of the panel that adjust the receiver's audio characteristics. The Dolby Pro Logic Center Mode button selects the Normal (center-channel bass split to the left and right front speakers), Phantom (no separate center channel), or Wide (full-bandwidth signal to the center speaker) setting for front center sound sources, and a bypass button disables the Dolby system. The Simulated Surround button toggles between simulated stereo from a mono source and three different simulated acoustic environments called Hall-1, Hall-2, and Stadium. The two Hall modes simulate the sonic properties of small and large concert halls, and Stadium provides the longer delays and more reverberant sound of a large stadium. The Front Straight button, effective with any of the simulated environments, removes all signal processing from the front channels, which receive unmodified left and right stereo signals, while continuing to send delayed signals to the surround channels.
A pair of narrow pushbuttons adjusts the surround-channel delay from 5 to 80 milliseconds (ms) in 5-ms steps (except in the Dolby Pro Logic mode, where the range is 15 to 30 ms). Similar controls adjust the center and surround volume in 2-dB steps. Finally, below the volume knob is a horizontal slider control that adjusts the level into the signal-processing circuits. Lights in the display window indicate the correct range of signal levels.
As might be expected, the rear apron of the RV-371 is well supplied with signal connectors, although the receiver's size keeps it from seeming unduly crowded. The tuner has inputs for a 75-ohm FM antenna and an AM loop antenna (supplied). A novel, and useful, feature is a small slide switch next to the phono-input jacks that converts them to an additional high-level input (Aux 2) for use in a system having no record-playing equipment.
The front, surround, and center preamplifier outputs and the corresponding power-amplifier inputs are joined by removable jumpers, providing added flexibility for using external power amplifiers or inserting other signal processors in the signal path. Similar jumpered in/out jacks are provided for connecting an external signal-processing accessory into the signal path between the input selectors and the remainder of the receiver's circuitry. There are also fixed-level output jacks for the front, surround, and center channels for use in multiroom installations, in which programs originating from the RV-371 might be amplified and controlled at a remote location independently of the receiver's own control settings.
The speaker outputs are five-way binding posts on 3/4-inch centers. Outputs are provided for two pairs of front speakers, selected by buttons on the front panel. Two of the four AC outlets are switched.
The basic power ratings of the Luxman RV-371's amplifiers are 70 watts each for the left and right front channels, 55 watts for the center channel, all into 8 ohms from 20 to 20,000 Hz at no more than 0.04 percent total harmonic distortion (THD). The surround channels are rated at 50 watts each with less than 0.05 percent distortion. The amplifiers are all rated for high dynamic power outputs into low-impedance loads (220 watts for the front channels into 2 ohms, for example).
The Luxman RV-371 weighs about 40 pounds and comes with an infrared remote control that not only duplicates virtually all of its front-panel functions but also incorporates the basic control functions of compatible Luxman CD and tape decks.
The FM tuner section was arguably the best we have seen as part of a complete receiver. Such important characteristics as capture ratio, image rejection, and alternate-channel selectivity were considerably better than average even compared with most separate tuners. Although the FM muting circuit silenced the receiver while it was being tuned, it would not engage once a station was acquired, no matter how low the signal strength dipped. And the tuner continued to operate in the stereo mode down to an unusually low signal level of 8 dBf (0.7 microvolt), though with increased noise. The FM frequency response was better than +/-1 dB from 25 to 15,000 Hz. Finally, there was absolutely no detectable leakage of the 19-kHz stereo pilot carrier or the internal 38-kHz stereo subcarrier in the audio outputs all the way down to the noise floor, which was below - 80 dB.
Besides these unusual measurable qualities (or perhaps because of them), the RV-371's FM tuner section sounded first-rate, providing some of the best FM reception we have heard in some time. The preamplifier section's frequency response was extremely flat, and the tone-control characteristics were good, hinged at about 1,000 Hz and having no effect on the response outside of their respective ranges.
The "subsonic" filter had a 6-dB-per-octave slope below about 20 Hz, which is adequate for reducing turntable rumble and similar noises, with no effect in the audible range. The loudness contours, which took effect at volume-control settings under -15 or -20 dB, boosted frequencies below about 200 Hz by 5 or 6 dB and those between 10,000 and 20,000 Hz by about 3 dB. The circuit's audible effect, like that of the tone controls, was relatively subtle. The phono preamplifier had very accurate RIAA equalization, and the phono-input stage overloaded at very safe levels.
As the specifications in the manual make clear, although the RV-371's amplifiers were specifically designed for driving 8-ohm loads, they also have considerable short-term current-delivering ability and can safely drive loads as low as 2 ohms to very high power levels with signal transients such as the standard EIA dynamic-headroom signal of 20 milliseconds (ms).
Our measurements confirmed Luxman's dynamic power specifications, which (like almost all of this receiver's ratings that we attempted to verify) are actually rather conservative. It is not usual to find a "70-watt" receiver or amplifier that can not only deliver 85 continuous watts into 8-ohm loads (and 144 watts into 4 ohms) but can also drive 2-ohm loads with 20-ms bursts of almost 300 watts!
Driving 8-ohm loads, the main front channels had a 1,000-Hz distortion level of only 0.015 percent in the range of 30 to 70 watts. The center channels distortion was about 0.1 percent from 3 to 80 watts into 8 ohms. The surround channels carry a multiple-echo delayed signal that prevents an accurate measurement of their distortion, but the amplifier was clearly able to deliver more than 70 watts from these channels before clipping occurred.
The Luxman RV-371, unlike some other deluxe A/V components, does not provide a large number of simulated acoustic environments or the means for the user to modify one extensively or to create entirely new ones. Wisely, its designers recognized the need for a top-quality A/V control and amplifier system that would deliver performance to meet the most critical listening standards without being unnecessarily complicated or difficult to use.
Although the receiver's front panel (to say nothing of its rear apron) might seem formidable at first glance, its major controls-the ones that would be used daily-are easily accessible and plainly marked. As a result, the RV-371 is not nearly as confusing as many other A/V receivers we have used. We found the limited number of preset acoustic environments to be more than adequate. They provide several distinctly different basic sound characteristics, and since the user has full control over the levels of all channels and the primary time delay in the surround channels, it is easy to adjust the final sound to taste.
We were also pleased to see that the several conventional response-modifying circuits (tone controls, loudness compensation, and infrasonic filter) were not designed with a heavy-handed approach. Each can do its intended job perfectly satisfactorily yet is unlikely to degrade the sound seriously even if misused.
A word to those who might look askance at double-digit power ratings in these days of triple-digit-rated amplifiers. The RV-371's ratings are conservative, and its amplifiers' tremendous dynamic power capability into low load impedances will enable the receiver to drive any speakers likely to be connected to it, with plenty of headroom to spare. There is a big plus to this design approach-the heat dissipation of the five amplifiers in the RV-371 is minimal in relation to its true music-playing capability. During our testing the top of the receiver never became more than slightly warm to the touch, in sharp contrast to the sizzling exterior temperatures we often encounter with power amplifiers.
Although we never used the RV-371 in a multiroom installation, the numerous available compatible Luxman accessories and components make this an intriguing possibility. We found the supplied remote control to be useful and convenient, although almost half of its sixty-four buttons are dedicated to other system components. It does control all the key functions of the receiver, and the functions of the color-coded buttons are clearly marked. Our only quibble is that the power and master volume buttons are too close together, making it too easy to shut the receiver off when you're trying to change the volume. Practice would minimize this annoyance, of course.
More significant is that in all important respects the RV-371's performance was good or better-and its outstanding FM tuner section sounded as good as it measured.