Sansui CD-X901 CD-player Review

Sansui’s CD-X901 compact disc player is part of its high-end Vintage series, which features premium-quality circuit components and mechanical construction intended to achieve the highest practical level of sonic performance.

The copper-clad steel chassis of the CD-X901 and separate copper-clad player mechanism, suspended from the main chassis on vibration isolators, are said to minimize mechanical resonances. A brushless and slotless motor and a new disc-centering system are claimed to provide additional vibration damping and an improved signal-to-noise ratio (S/N). The disc tray itself is made of a hard, precision-finished bulk molding compound. Even the two power transformers, one for the digital circuits and one for the analog circuits, are mounted on a separate, vibration-isolated copper-plated chassis. Additional noise reduction is provided by the use of three separate power supplies and optical-cou-pler isolation of the digital circuits from the analog sections.

The CD-X901 uses a single master clock system for the timing of its digital, servo, and control circuits, minimizing leakage of spurious signals into the outputs. Quadruple-oversampling (176.4-kHz) digital filters provide a smooth, ripple-free frequency response, and separate 16-bit digital-to-analog (D/A) converters maximize channel separation and eliminate phase shifts that would be caused by interchannel time delays.

The audio circuits use discrete components, rather than ic’s, for maximum performance. In addition to regular stereo audio outputs through gold-plated phono jacks, balanced audio outputs are provided through three-pin cannon connectors. The digital playback signal is also available, before conversion to analog form, through a standard phono jack. When this signal is fed to a digital processor or to an amplifier containing d/a converters, the analog section of the CD-X901 is bypassed.

Most of the controls of the Sansui CD-X901, all pushbuttons except a small headphone volume knob and a slide switch for external-timer operation, will be familiar to anyone who has used a CD player. They include fast search with audible sound, track skipping, and index-se-lection functions. A numerical keypad provides direct access to any numbered track. The player can be set to repeat one track, an entire disc, or any desired portion of a disc (“phrase repeat”). A spacing function automatically inserts a 4-second silent interval between tracks, and the music scan button plays the beginning of each track for 10 seconds before proceeding to the next track.

The player’s operating status is displayed in a large front-panel window in clear, easy-to-see amber numerals and words. When a disc is loaded, the display first shows the total number of tracks and playing time on the disc, then changes to the current track number and elapsed time. The window also contains a music calendar display, a matrix of twenty squares in which the track numbers on a disc appear like the dates on a calendar. As each is played, its number disappears.

The CD-X901 can be programmed to play up to twenty tracks (but not indexed portions) in any order. The program sequence can be checked (using the check key) while the machine is in stop mode, but not during operation. The checking function shows the playing time of each selected track, but not the time required for the transition between tracks; the selected track numbers appear on the MUSIC CALENDAR display.

The Sansui CD-X901 is a relatively large and heavy machine. It measures 17-3/4 inches wide, 16 inches deep, and 3-7/8 inches high. Supported on four large feet, it weighs 23 pounds. A wireless remote control is supplied that duplicates virtually all of the player’s front-panel controls, including the power switch and the track-selector keypad. Price: $1,400.

Lab Tests

The output voltage of the Sansui CD-X901, playing a 0-dB, 1,000-Hz track on a test CD, was 1.97 volts, with a channel imbalance of 0.18 dB. The player’s frequency response was +0.3, — 0 dB from 20 to 20,000 Hz. Its 1,000-Hz distortion (consisting only of third or fifth harmonics) was 0.0032 percent at 0 and —10 dB, but at — 20 dB a number of low-level spurious signals surrounded each harmonic component and prevented an accurate measurement with the spectrum analyzer. The total harmonic distortion (THD) plus noise at — 20 dB, however, was 0.021 percent.

The A-weighted noise level was — 106 dB, and the dynamic range was 101 dB, both excellent readings. The low-level linearity of the D/A converters was good, with errors of + 1 dB at — 80- and — 100-dB levels and a +2.3-dB error at —90 dB. The square-wave response was typical of CD players with digital filters but with low-amplitude ripples on a 1,000-Hz square wave. Channel separation was excellent, measuring 99 dB at 1,000 Hz and 95 dB at 10,000 Hz. The interchannel phase shift was undetectable (zero) from 1,000 to 10,000 Hz and a barely measurable 0.7 degree at 20,000 Hz. As with most CD players, there was a slight phase shift of 4 degrees between channels at 100 Hz.

The slew time between Tracks 1 and 15 of the Philips TS4 test disc was 3 seconds, an average figure for today’s CD players. The cueing accuracy was excellent, and the CD-X901 had no difficulty tracking the largest calibrated defects on the Philips TS5A test disc. The headphone volume with medium-impedance AKG K340 phones was excellent.

To our surprise, the Sansui CD-X901 was quite sensitive to impacts on its top cover. Even light finger tapping was sufficient to interrupt its playing, but relatively strong blows on the sides did not disturb its operation. Although our tests did not check the sensitivity of the player to vibration conducted through its mounting feet, we suspect that its isolation from that source of vibration would be much better than its isolation from top-plate excitation.

Comments

When we removed the top cover, we were most impressed by the complexity and ruggedness of the CD-X901’s internal metalwork as well as by the large number of electronic components that could be seen (many more were out of sight). At a time when many low-priced CD players consist of little more than a handful of circuit chips, Sansui’s all-out approach to the design of this product is notable. And for installations using the Sansui Vintage AU-X901 integrated amplifier, the CD-X901 offers the option of a fully balanced signal connection, from its audio outputs to the loudspeakers, that should make noise and interference from that source a thing of the past.

The CD-X901 lived up to its specifications in every important respect—when it fell a little short of meeting one figure, it surpassed another. Of course, it should be obvious to anyone who follows developments in the hi-fi world that small differences in measured performance rarely, if ever, have any effect on subjective qualities. To the extent that measurements can establish the worth of a product such as this, the CD-X901 is clearly one of the better CD players on the market. Its sound was as good as that of any other CD player we have heard, while its solid construction and smooth operating “feel” set it apart from lesser products.

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