Sansui RZ-9500AV A/V receiver Review

The Sansui RZ-9500AV is a versatile, powerful, yet affordably priced audio/video (A/V) receiver. Its main (stereo) power amplifier is conservatively rated at 100 watts per channel into 8-ohm loads from 20 to 20,000 Hz with no more than 0.02 percent total harmonic distortion (THD). In addition, the RZ-9500AV has a pair of 30-watt surround-channel (rear) amplifiers and a 40-watt center-channel (front) amplifier for use with its Dolby Pro Logic decoder.

Surround-sound capabilities aside, the RZ-9500AV is a stereo am/FM receiver with a digital frequency-synthesis tuner driving its power amplifiers through a versatile digitally controlled preamplifier. Except for a large volume knob, the operating controls are all pushbuttons, and almost all of them are duplicated on the infrared remote control supplied with the receiver (the volume knob is turned by a small motor in remote operation).

In addition to its tuner, the RZ-9500AV has inputs for CD and Phono sources and two audio tape recorders (Tape 1 is also labeled DAT but is equally suitable for an analog recorder). Other inputs provide for two VCR’s and a videodisc player.

The input-selector buttons form a row across the panel below the large display window. In another group are buttons that control the receiver’s signal-processing functions, including Dolby Pro Logic and three other surround modes—Natural, Hall, and Stadium. A SPACIAL button selects the degree of space enhancement, Normal or Wide, in any of the latter three modes. The source direct button completely bypasses all tone-control and surround circuits.

As many as four additional sets of surround parameters can be programmed by the user into the receiver’s memory and recalled at the touch of a button. The stored information can include relative channel levels, delay time, and tone-control settings. In the Dolby Surround mode, a center mode button toggles through Normal, Wide, Phantom, and off settings for reproduction of information encoded into the front center channel. A test tone button activates a pink-noise signal to simplify setting channel levels in Dolby Pro Logic playback. The test signal, in 2-second bursts, appears sequentially in the left, center, right, and rear channels. Three buttons near the headphone jack are used to connect either or both of the two pairs of main speaker outputs and the rear and center speakers.

The tuner control buttons select either normal am and fm reception or cable fm via a separate RF input connector. An auto/manual button selects automatic scan tuning or single-channel stepping with the up and down buttons above these controls. Inter-station-noise muting and automatic stereo/mono switching operate only in the auto-scan mode.

At the right of the panel are controls affecting the frequency response and gain of the amplifiers. The buttons marked TREBLE, BASS, and SUPER BASS alter the frequency response. Pressing any one of them triggers a numerical readout in the display window that shows its setting in 2-dB steps from +10 to -10 dB. The settings are adjusted with a pair of up/down buttons identical in size to the tuning controls. The Super Bass control operates principally below 100 Hz; the others have more conventional characteristics. There are also adjustments for the center and rear levels relative to the (main) front level. Pressing the small round balance button displays a bar graph of the relative levels in the left and right channels. Above these controls, near the volume knob, is a loudness-compensation button.

The display window, occupying much of the upper half of the panel, presents the receiver’s full operating status in legible orange or red fluorescent characters. The frequency of the tuned station, its preset channel number, and its call letters (if the user has programmed them into the preset memory) appear in large characters, and smaller characters are used for status indicators. To the right of the window is a keypad and other buttons used for storing up to thirty station frequencies in memory. The keypad also enables direct tuning to any station by frequency.

The RZ-9500AV’s rear apron holds an imposing array of input and output connectors and jacks. These include record and play jacks for two audio tape decks and the audio sections of two video recorders as well as video connectors for two VCR’s (both composite-video RCA jacks and S-video DIN sockets are provided). Similar connections are provided for a videodisc player, as are composite and S-video monitor outputs.

There are separate stereo preamplifier outputs and main-amplifier inputs for the front and rear channels and single-channel connectors for the mono center channel. A small knob adjusts the channel balance for the surround modes.

In addition to the signal inputs for phono and CD, there are separate 75-ohm coaxial fm inputs for an antenna and a cable feed and spring-loaded connectors for the supplied am loop antenna. The speaker outputs are all spring-loaded clips that accept the stripped ends of speaker wires. There are two switched AC outlets.

The remote control is designed to operate more than just this receiver, and it has a correspondingly large number of buttons. It is preprogrammed for Sansui CD players and cassette decks and can “learn” the commands needed for most other remote-controlled components.

The RZ-9500AV, like most other A/V receivers, is fairly large and heavy. It measures 17 inches wide, 16-1/8 inches deep, and 5-7/8 inches high, and it weighs about 30-1/2 pounds. Price: $770.

Lab Tests

We tested the RZ-9500AV’s amplifiers with both front channels driving 8-ohm loads. (Although we used the receiver in a surround-sound system with both audio and video programs, we did not measure the performance of the surround and center channels.) The amplifiers were preconditioned by operating for 1 hour with each channel delivering 33 watts into 8 ohms.

The main amplifiers were considerably more powerful than rated, delivering a clipping output of 145 watts per channel into the 8-ohm loads at 1,000 Hz. Output into 4 ohms was an impressive 200 watts per channel, which encouraged us to try 2-ohm operation on one channel with the other driving 4 ohms. Output into the 2-ohm load, for which the unit definitely is not rated, was 218 watts. After those measurements, it was not too surprising to measure dynamic power outputs of 156, 253, and 306 watts into loads of 8, 4, and 2 ohms, respectively.

At no time during our tests or use did the receiver shut down or blow a fuse. The receiver’s power supply can be switched for safer operation into low-impedance loads, with some reduction in its output capability into higher impedances, but our tests suggest that this would be necessary only in unusual cases.

The distortion (into 8 ohms) was about 0.008 percent at most frequencies from 50 to 5,000 Hz and power outputs up to more than 50 watts. At the rated 100 watts, the distortion was less than 0.02 percent from 20 to 10.000 Hz, rising to 0.11 percent at 20.000 Hz. At 1,000 Hz, the distortion into an 8-ohm load was less than the rated 0.02 percent from a couple of watts up to well over the rated 100 watts. Readings were only slightly higher with 4-ohm loads: less than 0.03 percent up to more than 150 watts output. As with most amplifiers, the 2-ohm distortion figures were higher, but they were not at all excessive, reading about 0.04 percent up to 150 watts and 0.4 percent at 200 watts.

The CD input required a signal of 53 millivolts (mV) for a 1-watt reference output, with an A-weigh ted noise and hum level of -75.5 dB. Through the phono input the sensitivity was 0.29 mV, with a noise reading of -76.3 dB. The phono input overloaded at 1,000-Hz-equivalent levels between 150 and 185 mV from 20 to 20,000 Hz. The phono-input impedance was 50,000 ohms in parallel with 170 picofarads (pF), and phono frequency response was within +0.2, -0.7 dB of the RIAA curve from 20 to 20,000 Hz.

The bass and treble tone-control characteristics were conventional, with a sliding bass turnover frequency and treble curves hinged at about 1,500 Hz. The maximum range of the controls was somewhat less than average, however; they are rated at ±8 dB and sometimes measured slightly less. The Super Bass control’s effect was limited to frequencies below 200 Hz, and most of it was below 100 Hz.

Combining it with the normal bass control produced a 15- to 20-dB boost or cut at the lowest audio frequencies.

With all tone controls set to their flat-response points and no signal-processing circuits in operation, the preamplifier section’s audio frequency response was flat within ±0.02 dB from 20 to 2,000 Hz and down 1.5 dB at 20,000 Hz. In the Source Direct mode the response was within +0, -0.015 dB from 20 to 7,000 Hz and down 1 dB at 20,000 Hz. The loudness compensation boosted both low and high frequencies, with full effect at volume settings of - 20 dB or lower. The maximum boost was about 10 dB at 20 Hz and 8 dB at 20,000 Hz.

The fm tuner section had an excellent usable sensitivity (mono) of 9.8 dBf. The 50-dB quieting sensitivity was 13 dBf in mono and 35.5 dBf in stereo. The other tuner performance measurements were generally good, although the fm distortion was lowest at 65 dBf and increased slightly at higher signal levels. A similar effect was apparent in the AM-rejection measurement: It was a very good 71 dB at 45 dBf but fell to 56 dB at 65 dBf.

The FM frequency response was within +0, —1 dB from 30 to 15,000 Hz, and channel separation was better than 33 dB over the full range and better than 45 dB from 200 to 2,500 Hz. The am response was typically restricted, down 6 dB at 40 and 2,500 Hz.

Comments

Judged solely as a stereo receiver, the Sansui RZ-9500AV was an excellent performer overall, and its considerable power capability makes it a reasonable value at its price. Its FM tuner was one of the most sensitive we have encountered in a receiver and well above average in most of its other characteristics (the chief exception being its undistinguished image rejection, which would be of concern only in areas near busy airports). The AM tuner, despite its characteristically limited frequency response, sounded as good as any we have encountered in recent years.

In our use tests, the RZ-9500AV’s surround-sound capabilities were very satisfying. We used the Dolby Pro Logic mode with videodiscs and found the spatial effects to be as good as we have experienced in use tests of other A/v receivers. Although the RZ-9500AV does not have an independent adjustment of echo density, as some costlier surround systems do, it can vary the delay time from 10 to 150 milliseconds, more than enough for any reasonable need.

The RZ-9500AV is an impressively powerful receiver, and we were pleased to find that (unlike some other high-power models) it is not particularly vulnerable to abuse, which can sometimes result in expensive damage. Like all A/v receivers, it is a complex instrument and takes a bit of practice to use with full effectiveness. Fortunately, the instruction manual leaves little to the imagination, and the results are well worth the effort of mastering the receiver’s intricacies.

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