Sansui AV-7000 Audio/Video Amplifier Review

Sansui’s AV-7000 is a full-featured surround-sound A/V integrated amplifier whose video functions consist largely of signal-switching features. It has two sets of rear-apron video and audio input and output connectors for components such as a TV set and VCR, plus two more sets of inputs for a videodisc player and another video source. One set of the input connections can be switched to duplicate jacks on the front panel to simplify playback from a camcorder.

There are also provisions for connecting an external video processor (used to modify the appearance of the picture) and an output for driving a video monitor. All video signal connections provide both phono-type composite-video jacks and S-video jacks.

The AV-7000’s audio facilities include five channels of amplification (for front, center, and rear speakers in a surround-sound system) and a choice of six surround modes as well as normal two-channel stereo operation. In addition to Dolby Pro Logic decoding circuits, there is a Dolby 3 Stereo mode that “folds over” the surround channels into the two regular stereo speakers while still feeding the center channel to one or two center speakers. If the center speaker has limited low-frequency capability, the system can be set to send center-channel frequencies below 100 Hz to the left and right front speakers.

The other surround modes are identified as Natural, Stadium, Hall, and Matrix. According to the instruction manual, the Natural mode is designed for use with sources containing a rich echo component, and Stadium provides the sense of space experienced at outdoor concerts and sports events. Stadium is also the only one of the surround modes that provides output to the rear speakers from monophonic sources. The Hall mode, as its name implies, is intended to simulate the effect of a typical concert-hall environment. Matrix provides an unmodified signal to the front speakers, with a delay of the same signal fed to the rear speakers.

The audio-only inputs are identified as phono, tuner, CD, Tape 1/DAT, and Tape 2/Monitor. The selected source can be recorded on either tape deck, and tapes can be dubbed from Tape 1 to Tape 2 (but not in the other direction).

The AV-7000’s amplifiers are all rated to drive 8-ohm loads, from 20 to 20,000 Hz, with less than 0.02 percent total harmonic distortion (THD). The left, right, and center front amplifiers are all rated at 70 watts output and the rear amplifiers at 35 watts per channel.

The AV-7000's three front-channel amplifiers have separate preamplifier outputs and main-amplifier inputs joined by removable jumpers on the back panel. This simplifies using external amplifiers for greater power capability or to drive multiple speaker systems. There is also a line-level mono output, controlled by a front-panel knob, for driving a powered subwoofer.

All the input selectors and surround-sound selectors are pushbuttons, but most of the other controls are full-size knobs, clearly marked and easy to use. Across the bottom of the panel are bass, midrange and treble tone controls, level controls for the mono output and the input to the surround circuits, and a channel-balance knob. A video recording selector switches the program source to be recorded on a VCR connected to Video 1 or Video 2. The large volume knob, with a red LED serving as its pointer, is at the right of the display window. It is motor driven in remote operation.

Other pushbuttons switch the front speakers off and on, engage the videoprocessor loop, and switch the Video 3 inputs to their front-panel jacks. The CD direct button, usable only with the CD input, bypasses all tone controls and signal-processing circuits, connecting a CD player through the volume control directly to the front-channel power amplifiers.

The display window in the upper center of the panel shows the selected source in large letters and numerals and the status of other controls in smaller letters. To its right, two pairs of buttons control the levels of the rear and center channels; the relative settings (from +15 to -50 dB in 1-dB steps) are displayed in the window while the adjustment is being made. Another pair of buttons performs a similar function for delay time, which is adjustable in 1-millisecond (ms) steps from 0 to 100 ms except in the Dolby Pro Logic mode, where the range is limited to 15 to 30 ms by Dolby licensing requirements. The specific delay set for each surround mode is retained in memory until changed. The remaining front-panel features are the headphone jack (carrying only the front-channel program) and the large power pushbutton. In its off setting, a small red LED shows that the amplifier is in a standby mode, from which it can be turned on or off by the supplied remote control.

In addition to the many line-level input and output jacks, the AV-7000’s rear apron has three pairs of speaker-output binding posts, which accept only stripped wire ends (banana plugs cannot be used). The center-channel amplifier’s output can be routed to one or two speakers, and an adjacent switch adapts it to the different load impedances presented in these two modes. A pair of jacks enables the AV-7000 to tie a compatible Sansui cassette deck and CD player to its remote control. There are three AC outlets, one switched.

The AV-7000’s remote controller duplicates virtually all the operating functions of the amplifier and has buttons dedicated to compatible Sansui components. In addition, it can learn the commands for components from other manufacturers, making it an effective system remote control. The Sansui AV-7000 measures 17 inches wide, 17-3/8 inches deep, and 6-1/4 inches high, and it weighs 32 pounds. Price: $1,000.

Lab Tests

Our measurements were limited to the AV-7000’s audio functions, and then to only the main front channels except for clipping-level power measurements of the center channel. All three front channels clipped at about 88 watts into 8 ohms, corresponding to a clipping headroom of 1 dB. We also drove 4-ohm loads briefly, measuring a clipping level of 106 watts. Dynamic power output into 8 ohms was 120 watts, indicating a dynamic headroom of 2.34 dB. Into 4 and 2 ohms, respectively, dynamic power was 200 and 255 watts.

The 8-ohm power output versus frequency at a constant distortion of 0.1 percent was 88 watts from 400 to 10.000 Hz, decreasing to 84 watts at 20.000 Hz and 68 watts at 20 Hz. Into 4 ohms, the output was 106 watts from 2.000 to 3,000 Hz, dropping to 100 watts at 20,000 and 60 Hz and to 82 watts at 20 Hz.

The total harmonic distortion plus noise (THD + N) of one front channel into 8 ohms at the rated 70 watts was 0.044 percent over virtually the full audio range. The distortion at 1,000 Hz reached its minimum of 0.01 percent at 85 watts, just before clipping occurred. A spectrum analysis of the 1,000-Hz output distortion showed about 0.006 percent (excluding noise) at 1 watt and 70 watts output.

Frequency response through the CD Direct input was very flat (within 0.1 dB) from 10 to 10,000 Hz, falling to -0.5 dB at 30,000 Hz and -3.5 dB at 100.000 Hz. Even through the normal CD input, which included the tone controls and considerable internal circuitry in the signal path, the response was +0, - 0.2 dB from 70 to 20,000 Hz and -1 dB at 20 Hz.

The bass and treble tone controls affected only the frequency ranges below 200 Hz and above 2,000 Hz, and the midrange control affected most of the range between 100 and 10,000 Hz, though its maximum effect was much less than that of the other controls.

The RIAA phono equalization was also very accurate, varying +0.04, -0.4 dB from the standard response over a range of 26 to 20,000 Hz. Phono-input impedance was 48,000 ohms in parallel with 170 picofarads. The phono stage overloaded at about 150 millivolts (referred to 1,000 Hz) over the range of 20 to 20,000 Hz.

The amplifier’s input sensitivity for a 1-watt reference output was 18 millivolts (mV) through the CD inputs and 0.35 mV through the phono input. Its corresponding A-weighted noise levels, referred to 1 watt, were - 79.5 and -75.6 dB.

Comments

Despite its apparent complexity, the Sansui AV-7000 was very easy to install and operate (we used it in a four-speaker surround-sound system). Its controls proved to be logically placed, and their operation quickly became intuitive.

All we had to do to appreciate the signal-processing features was to push the buttons and listen. The differences between the several modes were plainly audible, and—as with most digital signal processing (DSP) components —one can get almost as much fun out of varying their parameters as from the subsequent listening.

The instruction manual was quite complete, and some time reading it would be well spent. All DSP components we have used call for some experimentation to achieve the best results, but almost any of their simulated environments is likely to be an improvement over ordinary two-channel stereo. The AV-7000 was no exception to this rule.

Using the AV-7000’s programmable remote control proved an unexpected pleasure. Most devices intended to provide complete system control are impossibly cluttered and illogically laid out. The remote control supplied with the AV-7000 was easily the best we have used so far. About half of its buttons are duplicates of the amplifier’s controls, identical in marking as well as function. The other buttons, in several logical groupings, are designed to operate a compatible Sansui tape deck, CD player, tuner, and equalizer, and no doubt they would be easy to control with this handset.

The real surprise came when we tried to program the controller for a totally different CD player, several years old and not of Sansui manufacture. The process was so quick and foolproof that within a few minutes we had the CD player at the beck and call of the AV-7000’s remote control, which was even easier to use for this purpose than the one that came with the player. Memorizing commands from the CD player’s remote took no more than a couple of seconds each and never required a second try (in sharp contrast to most “learning” remotes we have used in the past). Overall, using the AV-7000 was an unalloyed pleasure. Its straightforward operation, strong performance, and versatility make it a fine value among today’s A/V amplifiers.

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