Onkyo DX-7555 CD player
By Robert Deutsch • January, 2008

I first heard a CD player in my own system in 1984 or 1985, several years before I began writing for Stereophile. I was curious about the Compact Disc medium—I’d read about it, had listened to CDs in stores, and was eager to hear what they sounded like in my own system. I’d even bought a CD: the original-cast recording of 42nd Street, which I
already had on LP. One evening, a friend who worked for Sony and knew that I was an audiophile brought over his latest acquisition: a CDP- 501ES, the second from the top of Sony’s line of CD players. He also brought along a bunch of CDs, including some solo-piano discs, and Erich Kunzel and the Cincinnati Symphony’s then-famous recording of Tchaikovsky’s 1812 Overture (Telarc CD-80041).

We connected the Sony player to my system. My friend was most enthusiastic: “Listen to how quiet the ackground is! No ticks and pops like you get on records!” We listened to one of the solo-piano CDs. The sound was sharper, crisper than I’d been used to hearing from my Lps (footnote 1). And, yes, the background was very quiet—no ticks or pops.Promising. Then I put on the 1812 Overture. The background was still quiet, but—oh dear, when the massed strings came in, everything fell apart: a jumble of sound and lost definition, as if the entire string section had been replaced by a synthesizer. The brass at first seemed to fare better, but then I noticed an edge, a harshness that was distinctly less plausibly realistic than recordings of brass on LPs. The bass was good, tighter and more extended than on LP. And 42nd Street? The solo voices were well focused, but sounded somehow less natural, more artificial, and the soundstage depth that was present on the LP had been curtailed. Was this what they called “perfect sound forever”?
Trying not to put a damper on my friend’s enthusiasm, I made vaguely positive comments about the clarity and the lack of noise, but I wasn’t even slightly tempted to ask him if he could get me one of these players at the employee’s-discount price. It was at least another year before I found a CD player (the Philips-based Mission DAD7000) I liked enough to buy. By then, it was becoming obvious that CD was the format of the future, and that resistance was futile.

I have a feeling that if the first CD player I heard in my system had been an Onkyo DX-7555, my impression of the format would have been much more positive.

Description and Design
The DX-7555 matches the size and styling of Onkyo’s A-9555 integrated amplifier, which I reviewed in the September 2007 Stereophile, and shares with it several design features. Like the A-9555, the DX-7555’s front panel is brushed aluminum; it has a fairly heavy, antiresonant chassis, a power transformer of substantial size and weight, and features Onkyo’s proprietary Vector Linear Shaping Circuitry (VLSC), which is claimed to remove digital noise from the analog signal by using a comparator/feedback method. The digital-to-analog conversion is handled by a Wolfson Microelectronics WMA8740 24-bit/192kHz DAC. The digital clock is said to be highly precise (±1.5ppm) and to produce very low jitter.

The DX-7555’s Setup mode permits selection of analog output polarity and digital filter slope: Sharp (flat to 20kHz, with a steep cutoff after that) or Slow (gradual high-frequency rolloff, to better maintain audioband phase accuracy). An unusual feature of the player is that the frequency of its digital clock can be adjusted by the user to match specific CDs. I assume that this feature is included for the type of audiophile who feels compelled to adjust the cartridge VTA for every LP
and writes down the optimal setting on the record jacket. After a bit of fiddling, with inconclusive results, I left the clock frequency alone. The DX-7555 has optical and coaxial digital outputs, the digital signal having a “direct” path to the output through shielded cables, to protect the signal from noise and interference.

The DX-7555 has a full set of convenience features: headphone output with volume control, 25-step memory playback, four repeat modes, fourmode display dimmer, and Remote Interactive (RI) input/output jacks for integration with other Onkyo RI-enabled devices. The remote control has the same sort of logical layout that I praised in the A-9555’s remote,
with a large, distinctively shaped Play button, but doesn’t include controls for polarity and filter slope, which would have made these features more convenient to use.

Oh, and it looks really nice, with fit and finish that suggest a product from a high-end specialist manufacturer rather than a medium-priced mass-market offering.

I’ve always thought that the principle of “first do no harm” should be applied to designers of audio products as well as to physicians, and the folks at Onkyo seem to have followed this principle in designing the DX-7555. Listened to on its own, without explicit comparison to any other digital source, the DX-7555 impressed me as sounding smooth, and lacking the annoying harshness that I remember from that firstgeneration Sony player of more than two decades ago. It had an easyon- the-ears quality that allowed me to listen for long periods with no symptoms of the dreaded “listening fatigue.”

I don’t have a copy of the Telarc 1812 Overture—which, whatever its sonic qualities, is possibly the most boring nterpretation of the work on record—but I do have a Telarc sampler featuring recordings from that period, and the DX-7555’s presentation of orchestral sound was very pleasing, the string sections of orchestras sounding much like . . . well, string sections, and avoiding the squeaky chalk-on-a-blackboard effect that bad digital sound can produce. Just for old times’ sake, I also played 42nd Street. That was fine, too, except for the tap-dancing bits, which came across more as sound effects than as real tap. (This is very likely the fault of the recording itself; microphones have a difficult time
capturing the sound of tap.) I played my usual reference CDs: the Chesky Records Jazz Sampler and Audiophile Test Compact Disc, Vol.1 (Chesky JD37); Mickey Hart’s Planet Drum (Rykodisc RCD-10206); and Sylvia McNair’s Sure Thing: The Jerome Kern Songbook (Philips 442 129-2). There were no surprises, and the aural fatigue factor was again kept
to a minimum, but there was somewhat less of a sense of detail and transparency than I’ve heard before with these recordings.

Before I discuss specific comparisons with other CD players, I should talk about the effect of changing the DX-7555’s digital filter characteristics.You’ll recall that the Onkyo’s Setup mode allows selection of filter slopes:Sharp (steep) or Slow (gradual). These appear to correspond to the Measuring and Listening options of the Ayre CX-7e CD player, and, as I
note in the sidebar, I prefer the sound of the Ayre with this switch in the Listening position. With the Onkyo, however, my preference was the opposite: the Slow setting (corresponding to the Ayre’s Listening setting) was very laid-back, with somewhat better spatial definition, but it was just too soft-sounding—at least in my system, and for my taste. I went
back and forth several times between the two settings, using different CDs, and preferred Sharp every time. All of my comments about the sound of the DX-7555 are based on its filter slope being set to Sharp.

Trying to determine the contribution to a system’s sound of only one of its components is no easy task, and although introducing a new component into a familiar system is a good start at getting a handle on that product’s sound, I think it’s important to make direct comparisons with other components. In this case, I had two other digital sources on hand: the Ayre CX-7e, my new reference for high-end CD players (see sidebar); and the Marantz DV8400, a DVD-Video/Audio/SACD/CD player that I’ve had in my home theater for the last few years, and which was described by Kal Rubinson, in his “Music in the Round” column of May 2004 (Vol.27 No.5), as “a capable performer offering balanced sound,extended frequency range, and good soundstage imaging and depth,” though he noted that it “lacked a little in dynamics.”

In making these comparisons, I tried to control potentially confounding variables: I used the same pair of interconnects for each player or,where the comparison involved balanced outputs/inputs, balanced interconnects of the same make, model, and length. I matched output levels to within ±0.1dB, measuring voltage at the amplifier output using the sinewave level signal on Stereophile’s first Test CD (Stereophile STPH002-2), and using the volume control of my PS Audio GCC-100
integrated amplifier. The outputs of the Onkyo and the single-ended Ayre were pretty close to begin with, but the Ayre’s balanced output was considerably higher, and the Marantz’s single-ended output was quite a bit lower without compensation.

Comparing the single-ended output of the Ayre with the Onkyo, with their levels matched, it didn’t require a great deal of intensive listening to conclude that, as good as the Onkyo was, the Ayre was in a different league. The CX-7e revealed more instrumental detail and a wider, deeper soundstage, with more precise spatial definition of instruments
and voices within the stage. Music reproduced by the Ayre was more engaging, with a dynamic thrust that made the Onkyo sound slow in comparison (and remember, this was not with the Onkyo’s digital filter set to Slow). The Ayre achieved this without its sound becoming too forward or clinical—a difficult balance for any audio component to
achieve. The Ayre’s treble was not more extended than the Onkyo’s in any obvious way, but the bells and other treble percussive instruments on track 3 of the Chesky test disc had a more pristine clarity through the Ayre. The bass was seemingly deeper in extension, and more clearly defined—an effect particularly evident when I played Mickey Hart’s Planet

These differences were even more obvious when the comparison was with the Ayre’s balanced output, this no doubt related to the fact that the PS Audio GCC-100’s circuitry is also fully balanced. Dynamics were more powerful still, a related effect being that, after listening to a CD on the Onkyo, and then to the same disc on the Ayre via its balanced outputs,
the sound actually seemed louder. I even checked my settings to make sure I hadn’t somehow failed to correctly match the levels, but the settings were correct. The Ayre CX-7e sells for $2950, almost five times the price of the Onkyo DX-7555, so it should sound better. It definitely
Comparing the Onkyo DX-7555 with the Marantz DV8400 was a different story. I seldom listen to CDs in my ome-theater system, but when I have, my impression of the Marantz has been much like Kal’s: “a capable performer,” indeed. This impression persisted when I listened to the Marantz in my two-channel system, but when I switched to the Onkyo, it
was apparent that the Onkyo had better dynamics, greater clarity, and more extended treble—call it a more-than-capable performer. Of course, the Onkyo plays only CDs—the Marantz also plays DVDs (with excellent video quality), DVD-As, and SACDs, and a good deal of its $1695 cost is to pay for these capabilities. Still, considering the DV8400 as only a CD
player, I felt the Onkyo was superior.

The end of the road
A few days before it was time to pack up the Onkyo DX-7555 and send it off to John Atkinson to be measured, I hooked it up to the Onkyo A-9555 integrated amplifier. The combination worked beautifully—not surprising, given that they have many of the same technical design features, and were launched at the same time. And both components seem cut from the same sonic cloth, sounding smooth, laid-back, and slightly soft (the A-9555 perhaps a bit more than the DX-7555), and neither is particularly strong in dynamics. The combo of the Ayre CX-7e CD player and the PS Audio GCC-100 integrated is capable of producing sound that’s more transparent to the source, and better at communicating the excitement of music. If you told me you had $6000 to spend on a CD player and integrated amplifier, I’d recommend the Ayre and the PSA. Still, the Onkyo pairing at just over one fifth the price produced a very comfortable sound that was simply very pleasant to listen to, and is likely to be more tolerant of excessive brightness and treble roughness in speakers. The DX-7555 at $599 and the A-9555 at $699 represent excellent value and are highly recommended.

Footnote 1: My system at the time consisted of a Linn turntable and tonearm and, I think, a Supex cartridge; a Conrad-Johnson PV-2ar tube preamp; a Luxman MQ-68c tube power amplifier for the top and a Bryston 3B solid-state amp for the bottom; and original Quad speakers paired with Cizek MG-27 subwoofers. The sound was uncommonly smooth, and not prone to exaggerating faults in the source.