Mitsubishi DP-311R CD-player Review

The DP-311R, the top of Mitsubishi’s line of CD players, features an unusual physical construction as well as advanced circuit design. It is probably the most compact CD player designed for home rather than portable use, yet it offers virtually all of the operating conveniences found in any current model as well as some unique features.

The DP-311R gives new meaning to the term “low profile.” Its height of less than 2-3/8 inches, including the 3/8-inch protrusion of its massive supporting feet, is close to the minimum possible for a front-loading player with a motor-driven drawer. It is 16-3/4 inches wide and 13 inches deep and it weighs 14 pounds. The main operating controls are conventional soft-touch pushbuttons for two-speed fast search in both directions with audible sound, track skip in both directions, stop/clear, play/ pause, and disc-drawer open/close. Above them are smaller buttons for programming a selected playback sequence and for repeating a disc, track, programmed sequence, or defined phrase. There is also a button marked phase. According to Mitsubishi, some CD’s are mastered with the channels out of phase, and pressing the phase button on the DP-311R player reverses the phase of one channel, restoring the correct phase relation (as determined by listening).

Small buttons at the top of the panel provide direct access to any track on a disc and are used to program playback of up to thirty-six selections in any order. The fluorescent display window contains the now-standard “music calendar” matrix, which shows all the track numbers (up to a maximum of twenty) when a disc is loaded, extinguishing them one by one as the tracks are played. In programmed operation, only the numbers of the selected tracks appear in this display. Other indications include the current track and index number, total number of tracks programmed, and elapsed time of the current track. A button above the window switches the display to show the remaining time on the disc and the position of the current track in the programmed sequence. Pressing the button again extinguishes the entire display, and a third press restores the initial display information. According to Mitsubishi, the option of switching off the display is provided to eliminate even the minute amount of noise contributed by its operation.

The circuit configuration of the DP-311R includes quadruple-over-sampling digital filters, analog filters, and a separate digital-to-analog (d/a) converter for each channel. Separate power supplies are used for the digital, analog, and servo circuits. To minimize interference between the three-spot laser pickup’s output and the digital-preamplifier stages, the preamplifier circuits are built into the pickup itself. The disc-drive’s tracking mechanism uses a linear motor and a floating suspension to minimize the effects of external vibrations.

Mechanical rigidity and immunity to vibration effects were key goals in the design of the DP-311R. It is constructed on a die-cast base, and thick metal partitions separate the four basic sections: the drive mechanism, digital circuits, analog circuits, and power supplies. The player is supported at each corner by an antivibration column that measures 1-1/2 inches in diameter. In addition, the top of the player is stiffened (and possibly damped) by two large plastic panels that are rigidly screwed to its metal cover.

The wireless remote control supplied with the DP-311R duplicates all of its front-panel controls except the power switch. It also provides buttons for index selection and for checking or clearing a programmed sequence.

The performance specifications of most CD players are very much alike, but a few of the DP-311R’s specs surpass those of many other machines. Specifically, its frequency response is rated as 4 to 20,000 Hz ±0.3 dB, dynamic range as better than 96 dB, signal-to-noise ratio (S/N) as greater than 105 dB, and 1.000-Hz channel separation as better than 100 dB. Price: $740.

Lab Tests

The output into a standard EIA load (10,000 ohms in parallel with a 1.000-picofarad capacitance) from the 0-dB level of a test disc was 2.08 volts, with a channel imbalance of 0.25 dB. The A-weighted S/N was a very good 106 dB, and the dynamic range was 96 dB, both confirming the manufacturer’s ratings. The channel separation of 125 dB at 100 Hz decreased to 110 dB at 1,000 Hz and 83 dB at 20,000 Hz. The low-level nonlinearity of the d/a converters was not significant, measuring — 0.7 dB at a —80-dB level, — 3.3 dB at —90 dB, and —4.4 dB at — 100 dB. The interchannel phase shift was the lowest we have ever measured from a CD player, 0 degrees from 1,000 to 20,000 Hz and a mere 4 degrees at 100 Hz. The extremely flat frequency response required the most expanded scale of our plotter to show its variations, which were within +0.05, — 0 dB from 20 to 20,000 Hz.

The linear servomotor of the DP-311R slewed the pickup from Track 1 to Track 15 of the Philips TS4 test disc in about 1 second, matching the fastest players we have used in the past. Its cueing was exact even when there was no silent interval between the tracks, and it had no difficulty tracking the largest defects on the Philips TS5A test disc. Finally, the player withstood hard raps and slaps on almost any part of its exterior without mistracking, earning an A grade overall and a B+ directly over the disc mechanism, where hard blows did cause some mistracking. No amount of shock administered to the thin metal shelf on which it rested had the slightest effect on its performance.

Comments

It is not easy to maintain a high pitch of enthusiasm after testing dozens of largely excellent CD players, most of which look and sound like clones of some master player. This is not to denigrate today’s CD players, which are superb performers and certainly among the best values in component hi-fi. But even the players that depart from the norm seem to provide few surprises these days.

The Mitsubishi DP-311R was one of those rare examples of a different approach to design and packaging that really makes sense and produces verifiable performance advantages. Upon opening its carton, I thought it was just another small, inexpensive player, but picking it up disabused me of that notion (as did its price tag). It is one of the most solid-feeling audio components I have examined, with none of the hollowness or flimsiness typical of similar products. In fact, it feels as though it were machined out of a solid block of metal, and its weight seems out of proportion to its size.

Some other CD players also feature rugged mechanical construction, but they tend to be quite large and are not always as rigid and resonance-free as might be expected. The DP-311R is rigid and free of resonance, qualities that contribute to the way it ignores severe mechanical impacts, to say nothing of vibration. I suspect that its low profile (you could lose it under a newspaper) also has a lot to do with this characteristic.

Otherwise, the player matched or surpassed all but one of its rather impressive specifications. The only exception was its distortion level, 0.0045 percent thd + noise instead of 0.002 percent—a totally trivial difference. The display did not give us that “Ginza at night” feeling, nor did it contribute detectably to the player’s noise level, which was lower than that of most others. Although the phase switch did not disclose any case of recorded phase reversal on the discs we played, it might come in handy if you have a large collection of CD’s.

Did the DP-311R sound any different from other CD players? Not in any tests we were able to make. Was it different in any genuine, substantive respect? Definitely! Opening and closing the disc drawer and cueing up any part of a disc took place in total silence, and so rapidly that we were rarely aware of any delay. The DP-311R was as unobtrusive mechanically as it was visually and physically.

The combination of external simplicity and internal integrity that this CD player offers is rare but fortunately not extinct among consumer products that sell for less than stratospheric prices. There is little of value that could have been added to the DP-311R, and unless you need some feature it lacks, it would be hard to find a better CD player.

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