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The Carver SD/A-390t five-disc carousel-type CD changer offers an exceptionally large complement of operating features, including such unusual items as vacuum-tube output stages and a Soft EQ circuit that is said to make some discs sound much like top-quality vinyl LP records played with an audiophile-grade turntable/arm/cartridge combination.
DIMENSIONS: 17 INCHES WIDE, 4 3/4 INCHES HIGH, 16 INCHES DEEP
Basically, however, the SD/A-390t resembles and operates like a number of other carousel CD changers. It has a relatively deep chassis, necessary to accommodate the large drawer with its five shallow disc wells. When the drawer is opened by a touch of a button on the panel (or on the supplied remote control), three of the disc wells are readily accessible, but the two rearmost ones (Nos. 1 and 5) are partly blocked by the front edge of the cabinet. Some care may be needed when loading or unloading discs from the rearmost positions to avoid scratching them.
Conveniently, the drawer can be opened during operation without disturbing playback of the currently selected disc (which is effectively removed from contact with the carousel). That makes it possible to change up to four of the discs while still playing the fifth.
The changer can be programmed to play as many as twenty tracks, in any order, from any of the five discs. It can also be set to repeat indefinitely any single track, any disc, or all of the discs. Its random-play mode can be applied to all the tracks on a disc, to all the discs, or to a group of programmed selections on any or all discs.
For all its versatility, the SD/A-390t presents a relatively uncluttered appearance. The disc drawer occupies most of the upper part of the front panel (not unlike that of a videodisc player). Below it is the display window and a row of small buttons used for track selection and programming. The right end of the panel contains five more small buttons, for disc selection, and larger ones for opening and closing the drawer, advancing the disc-tray position in either direction, and the conventional stop, pause, and play functions: This area also contains the Soft EQ button and the receiving sensor for the infrared remote control. At the left side of the panel are a stereo headphone jack, its volume control, and a large, square power button.
The display window’s dominant feature is a row of seven numerals. Except for the leftmost, which is slightly larger, they are the same size (about ¼ inch high) and very close together. To their right, five smaller numerals enclosed in circles indicate the presence of discs in the carousel’s wells. Other words and symbols appear in the window as required to show the changer’s current operating mode.
The program level at one pair of rear-apron analog output jacks is fixed, but another pair carries a vari able-level signal. There is also a standard coaxial digital output that is unaffected by any of the user controls.
The remote control’s thirty-six but tons duplicate the front-panel controls and add quite a few more. Among these are buttons for the programming, repeat, and random-play functions, plus one that switches the time display to show the time remaining on the current track or on the disc (the default display is the elapsed time on the current track). Besides up and down buttons to control the level at the player’s variable output, the remote has a Level File button that can be used to store volume settings for as many as a hundred discs. When any of these discs is subsequently played, the changer automatically adjusts the variable output level to the stored value (any stored level can easily be erased). Operating the level controls or pressing the Level File button temporarily replaces the normal elapsed-time indication with a volume display.
With Soft EQ off, the SD/A-390t’s frequency response was quite flat, with just a small (0.2-dB) bump centered at 14 kHz. Switching on the Soft EQ boosted the output below 2 kHz, with a broad maximum of + 1.8 dB (relative to the 1-kHz level) in the range below 100 Hz. Although that response variation appears large relative to the normal deviations of this and other CD players, it is actually rather small in the context of overall system response. All other measurements were made with Soft EQ off.
Distortion across the audio frequency range was higher than for most CD players we have tested, but not by what we would consider a significant amount. Below a —20-dB recorded level, the 1-kHz total harmonic distortion plus noise (THD + N) was a constant (and negligible) —93 dB, but it rose rapidly at higher levels, to a maxi mum of —66 dB (0.05 percent) at or near the 0-dB (maximum) level. Although that reading is markedly higher than average for a CD player, it is still well below the threshold of audibility. Noise was typical for a good CD player and thus also completely inaudible.
The low-level linearity of the SD/A 390t’s dual MASH digital-to-analog (D/A) converters was as good as we have come to expect from CD players using this and other single-bit converters. The linearity error at levels between —60 and —90 dB did not exceed a fraction of a decibel.
=== == MEASUREMENTS == ====
Maximum output level 1.75 volts
Frequency response (Soft EQ off/on)
off 20Hz to 20kHz +0,2. —0.1 dB
on 20 Hz to 20 kHz +1.8, —0.6dB
100Hz -- 106dB
1kHz -- 95dB
20kHz -- 69dB
Signal-to-noise ratio (A-wtd.) 103 dB
Dynamic range 98.4 dB
Quantization noise -91.0dB
1 kHz (—80 to 0 dB) 0.0023 to 0.05%
20Hz to 20kHz (0 dB) 0.006 to 0.05%
Linearity error (at —90dB) +0.6dB
Maximum interchannel phase shift (at 20k Hz) 1.5 degrees
Defect tracking (Pierre Verany #2 test disc) 1,500 um
Slowing time: 2.5 seconds
Disc-change time 8 to 9 seconds
Impact resistance top and sides, B +
=== == == ===
Channel separation was identical in both directions (left to right and right to left) and much more than adequate. The output level was slightly (negligibly) lower than the 2-volt standard for CD players.
The SD/A-390t performed flawlessly in our listening tests. It was relatively insensitive to physical shock, requiring a rather hard slap on either the top or side to induce skipping while playing a disc. It was able to track through disc defects of 1,500 micro meters without audible errors, al though a 2,000-micrometer flaw produced audible mistracking ticks. Stewing between tracks was reason ably fast (2.5 seconds from Track 1 to Track 15 of the Philips TS4 test disc), and a disc change required 8 to 9 seconds. As with most other CD changers we have used, a disc change is accompanied by quite audible mechanical noise. The headphone volume was good.
Although the SD/A-390t is one of the most versatile CD players we have tested, it has its idiosyncrasies. Probably its most annoying characteristic was the close spacing of the identical- size numerals in its display. From a distance of more than a few feet, it was difficult to interpret the string of six numbers all jammed together. Another annoyance concerned the use of the remote control, which is essential for operating many of the changer’s features. The infrared receiving window on the player’s front panel is at the extreme right end, and we found that simply pointing the remote at the panel in general (especially when close to the player) was not always effective; it was sometimes necessary to carefully aim the handset at the window.
On the plus side, despite the SD/A 390t’s exceptional (and not always conventional) versatility, its instruction manual was a model of clarity, explaining in plain English the effect of each control and how to use the player’s numerous special functions. With its aid, we confirmed that everything worked as claimed.
What about the Soft EQ? Its purpose is to compensate for poor mastering practices that have left some CD’s sounding harsher and less ambient than their analog counterparts, especially old CD’s based on masters originally intended for LP’s. While allowing that with some speakers Soft EQ produces almost no audible effect and that not all CD’s will benefit from the processing, the manual does claim that with the right (or wrong, depending on your point of view) CD and speakers, a “discriminating listener will immediately notice a significant improvement.” The most I ever heard from it was a minute increase in the lower midrange and bass—hardly what I would call a significant change. But evaluating this feature is a totally subjective judgment that each listener must make for himself.
The matter of the vacuum-tube out puts falls in much the same category; if you believe in the special qualities of “tube sound,” you may well find them present in this case. The only tube-like characteristics I was able to positively identify were the warm-up time of 30 seconds or so and the slightly higher distortion readings (by no means a monopoly of tubes). Carver says the tubes are run well below their capacity and therefore should not deteriorate or need replacement over the life of the changer.
Overall, though, the Carver SD/A 390t is certainly a versatile CD changer that manages to do more with fewer controls than one would think possible prior to hands-on experience with it. Apart from the previous criticisms of its display and remote-control characteristics, I could not find anything about its operation and performance that was less than tops.
From: Stereo Review (June 1993)/ JULIAN HIRSCH -- HIRSCH-HOUCK LABORATORIES
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