Aiwa DX-C100M CD-changer
Compact disc changers have established themselves strongly in the market by virtue of their excellent value, since they usually do not sacrifice any significant element of performance to achieve their automatic changing functions. Most multidisc CD players are designed to provide several hours of essentially uninterrupted playback. A few go well beyond that function, serving also as music libraries and providing swift access to as many as a hundred discs stored within the player.
At the same time, they typically offer the full range of programming modes and operating flexibility found in any good single-play model.
The new Aiwa DX-C100M is the latest hundred-disc changer to reach us for testing. Though relatively inexpensive, light, and compact, it provides all the operating features one could wish for. Its shape is suggestive of a rather compact tower-format personal computer, relatively high and deep, with a narrow front panel. A see-through vertical window on the panel provides a view of the colorfully illuminated disc stack and the mechanical action inside as discs are moved between the playing position and their storage slots.
The DX-C100M stores discs, stacked horizontally, in a vertical magazine about 10 inches high. To play a disc, a shuttling mechanism inside the player travels to the selected slot, removes the disc, and carries it to the playback mechanism near the bottom of the chassis. At the end of play, the process is reversed.
During actual playback, the DX-C100M behaves much like any conventional single-play CD player. It is programmable to play any sequence of tracks, to a maximum of ninety-nine selections, or to repeat any one disc or all the discs indefinitely. It can also play the tracks on a disc in random order or even discs and tracks in random order, selecting a disc at random and playing the tracks on it in random order, then selecting another disc at random, and so on. The DX-C100M's slide-out disc drawer, used for loading and unloading CD's, can also accept and play a single disc, independent of those loaded into the magazine.
On the back of the player are the standard audio output jacks as well as an optical digital output and two pairs of input jacks marked AUX 1 and AUX 2. The inputs can be used to augment those of an associated amplifier or receiver in need of more line-level input jacks (typically identified as auxiliary inputs). Additional signal sources attached to the DX-C100M's inputs can be switched through it to the amplifier's CD inputs, in effect adding two more auxiliary inputs to the system.
Another way the auxiliary inputs can be used is to daisy-chain multiple changers, connecting the outputs of one DX-C100M to the aux 1 or aux 2 input jacks on a second, and so on. Each changer in the chain can be assigned its own unit number, enabling you to operate all of the functions of each one from a single remote control. Not many of us will ever require playback programming of 200 or 300 CD's, but should the need arise, this is certainly the least expensive way to satisfy it!
Besides the usual power switch and transport controls, the DX-C100M's front panel has ten numbered track/ disc selector buttons and a small button that sequentially switches the output jacks between CD, aux 1, and aux 2 signals. The panel also has a small display window showing the numbers of the disc and track being played along with a twenty-track music calendar for the disc currently playing. The player's infrared remote control duplicates all its front-panel functions and adds power, volume, and "function" buttons for use with certain Aiwa audio systems.
The DX-C100M comes with a comprehensive instruction manual (in Spanish and French as well as English), which is fortunate, since it is not always obvious from the control markings how to go about using and programming the changer. The sequence of button entries required to program it differs from what we have encountered on other CD changers, but a bit of experience with the manual at hand should get you on the right track pretty quickly.
The action in the disc magazine is intriguing to watch (and hear - it is quite audible) as the shuttle mechanism goes to the selected slot (first returning the previous disc, if any, to its rightful place) and carries the disc down to the spindle before parking itself. One effect of all that activity is to give the player an unusually long disc-change time - about 22 seconds - whether one selects an adjacent disc or one at the other end of the magazine. We also noted that in its normal programmed mode, even track changes within the same disc could take several seconds. Unprogrammed operation was as rapid and uncomplicated as one could wish for, however.
The Aiwa DX-C100M was able to track through 1,000-micrometer information-layer gaps without difficulty. A gap of 1,250 micrometers occasionally resulted in a brief "tick," and larger gaps could interrupt the playback more seriously. This behavior is acceptable (no undamaged disc should present any tracking problems), although some CD players can cope with considerably larger interruptions.
The output voltage from a maxi-mum-level (0-dB) signal was about 1.3 volts, considerably (about 4 dB) below the nominally standard 2 volts, although this is unlikely to present any problem in normal operation. Channel separation, though not as great as with many other CD players, was more than sufficient for subjectively complete isolation between channels.
Distortion (total harmonic distortion plus noise) was typically well below the manufacturer's 0.03-percent rating. A spectrum analysis of the output from a 0-dB, 1-kHz recorded signal, excluding noise from the measurement, showed distortion components (principally third and fifth harmonics) whose total rms value was 0.006 percent. Aiwa says the DX-C100M uses 1-bit digital-to-analog (D/A) converters with four-times-oversampling digital filters, so we were not surprised to find very good low-level linearity. The output from a -80-dB recorded signal was within a fraction of a decibel of its nominal value, although the error increased to about 2 dB at the -90-dB level. Interchannel phase shift was negligible.
Immunity to external shock and vibration was outstanding. No nondestructive impact we could apply to the player's exterior by hand produced any audible effect on the program.
The Aiwa DX-C100M is a well-built, highly versatile CD changer with more features than most of us would ever be likely to need. Its price is attractive, and its compact dimensions could make it a logical choice in many installations where some other megachangers might not fit easily. Like many other products that offer unusual or exceptional capabilities, it requires some practice for most effective use. In this case, that effort will surely yield substantial dividends.
