Product Review - Musical Fidelity X-DAC
Outboard Digital-to-Analog Converter - July, 1997
Daniel Long
Click here for larger image
Musical Fidelity X-DAC HDCD Digital-to-Analogue Converter THD: <0.02% 20Hz-20kHz Unweighted, <0.008% 20Hz-20kHz "A" weighted; Frequency Response: �0.2dB 20Hz-20kHz; S/N ratio: better than 90dB Unweighted, better than 100dB "A" weighted; Conversion type: 18-bit Co-phase 8x oversampled; Power Requirement: 12V AC 500mA (via mains adapter supplied); Dimensions (mm): 110 x 110 x 220 (W x H x D), width and height include feet; S$799, US$499.
Introduction
Are you happy with your CD player? Chances are you are but you keep hearing about this new
HDCD thing. High Density Compact Disk? Don't laugh! In our corner of the woods, that's the
translation that comes to mind when you mention HDCD, not High Definition Compatible
Digital. What a mouth-full! It's a wonder it's caught on, much less taken off.
So that is the question, isn't it. Has it taken off? Well, when you can find HDCD
processing in players anyone can just pick up off the shelf at an audio store without
having to stop by and rob a bank on the way, then I guess it has.
X-DAC
The X-DAC is another of Musical Fidelity's X-Series of budget performance components to be
introduced. The first was the (insert drum-roll here) X-10D Tube Line Stage. I first saw
the X-DAC at one of my usual Friday evening hangouts, Margil Hi-Fi (you see them in a
photo accompanying Robert Harley's coverage of the Singapore HEX show an issue of
Stereophile last year). Just sitting there. Couldn't believe my eyes when I saw HDCD on
the round front face. I had to take it home.
The X-DAC is a DAC (Duh), designed to be added to existing CD players with digital outputs
(if you have a dedicated transport, you probably haven't considered a DAC that costs less
to build than your transport's front panel). It sports two digital inputs, a coax on RCA
and Toslink. Output is via two sets of RCA. Unfortunately, because of how much it costs
(or, rather, how much it doesn't cost), it won't pass digital signals on (to drive
DAT/MD/CD-R decks etc.)
If you read other audio magazines, you probably know how the X-DAC looks (other than like
the X-10D). It's certainly not like a conventional audio component. The cylinder is black,
and the front panels are brushed aluminum, with 6 LEDs mounted on the latter. The X-DAC
will lock on to 48kHz, 44.1kHz and 32kHz, so there's one LED for each of these as well as
"lock", plus one each for "power" and "HDCD". The LEDs are
BIG and BRIGHT! So BIG and BRIGHT that if I turned off all the lights in my living room in
the evenings, I can read CD labels from about 2' away! By the way, the LEDs are not the
same colour; one's green, four are red, and the last one's yellow. First time I powered it
up, Bernadette (my 2.5 year-old) immediately went round wishing everyone "Merry
Chhhhhhristmas!".
Innards
Since I actually paid money for the X-DAC, I really didn't want to open the cylinder up
for a look inside. This nice person at Margil's actually offered to show me what the X-DAC
looked like inside and he opened a showroom piece.
The input receiver is a Yamaha, then the input (whether through the coax or the Toslink
via an opto-coupler) is cleaned up some before processing by the PMD-100 HDCD chip. What
this does is dig out the information hidden in the LSB (least significant bit) of the
16-bit PCM sampled word and use it to precisely decode the high-resolution signal, and
output this in a form appropriate to the DAC used. In this case, an 18-bit Burr-Brown
Co-phase DAC, which uses bitstream conversion for the lower bits and R-2R multibit
conversion for the higher bits. This is to take advantage of both the low-level detail and
resolution of bitstream and the solid bass response and timing of multibit.
How it sounds
I connected the X-DAC to both my LD players (a Pioneer CLD-D770 and CLD-D780; the 770 is
the same model as the US Pioneer CLD-703D) using the coax and the Toslink connections
respectively. It in turn fed my Audio Alchemy DLC which drives a NAD 218THX. Speakers are
the trusty Mirage M1090Is, driven full range.
I used a great number of CDs in my tests, including both HDCD-encoded and regular non-HDCD
good and bad sounding ones (I include a full list at the end of this review). My
particular reference is the Pioneer CLD-D770 which uses Pioneer's Legato Link. The Pioneer
is clean sounding and can be a little lean in the low to mid-bass. It is fairly extended
at the frequency extremes but not especially so; this is surprising given that Legato Link
actually tries to re-create frequencies above the audible spectrum, and therefore the
Pioneer should have sounded airier than it does.
The X-DAC was superior in every way to the Pioneer, save one. Let me start at the top.
While the Pioneer was fairly extended, the higher treble had a grainy texture much like
medium quality silk: on first inspection it impresses, but after some wearing, you start
to think about having something better.
The X-DAC, on the other hand, defines silky. I have never heard treble as I have after
inserting the X-DAC into the system. It wasn't up front and brash but rather smooth and
understated, always pleasing, never aggressive. Cymbals were shimmery in their quality,
never hissy unless it was so on the recording. There was, however, one particular
recording that gave the X-DAC a hard time: this was the Mapleshade recording of Clifford
Brown Live at Ethell's. The drum kit high-hats here were a little splashy and listening to
track after track here was a wearing. So maybe there is a little forwardness in the mid-
to extreme treble in the X-DAC. I didn't notice this on other CDs, however, if they were
well recorded.
Moving down to the upper-, middle- and lower- mids, again this is where the X-DAC
excelled. Vocals were presented with such presence, especially with female singers such as
Rebecca Pidgeon, Janis Ian, Jennifer Warnes, and Linda Ronstadt. Each of these ladies have
their very own particular style, and none was lost or obscured by the X-DAC.
So the only area where the Pioneer took the honours (and only just) was in the extreme low
end. The very deepest bass on recordings such as RR's Pomp & Pipes shuddered the room
to a greater extent with the Pioneer than with the X-DAC. This was really not apparent on
most music recordings anyway since my Mirages roll off at about 30Hz. The X-DAC was,
however, warmer sounding and fuller in the mid-bass, though only marginally so. This was
not a bad thing if you have a lean sounding setup.
If I had to describe the X-DAC as a whole, rather than a sum of parts, I think I would
call its presentation detailed and coherent across the entire spectrum. It sounds rather
laid back, and the music comes from deep within the soundstage. As a measure of how well
the X-DAC re-creates the recording venue, on CDs with ambience well recorded, the front
half of my listening space (of which my speakers occupy the front edge) disappears to be
replaced by wherever the CD takes me.
One last aspect of the X-DAC's performance is pace. I guess this is the least describable
of any audio component's qualities. With the X-DAC, however, whenever I played an upbeat
piece (would you call MJ's Black or White off his Dangerous CD upbeat?), we noticed my son
would start bobbing his head in time and shaking his booty (whatever that is!). And
frequently, we were worried he would get a sore neck! I guess that's pace.
Conclusion
Overall, I think the X-DAC represents an almost unbelievable bargain. I have not had the
opportunity of hearing superlative converters like the Mark Levinsons or the Spectrals and
though I am quite sure you get your money's worth with either of these state of the art
DACs, the X-DAC is the perfect upgrade for those who've been waiting for the entry cost of
HDCD to come down.
So, it is not recommended. It's mandatory.
CDs used:
HDCD
1997 CES Sampler, Stephen Stills - Manassas, Jimi Hendrix - The Ultimate Experience, Mark
Knopfler - Golden Heart, Mickey Hart - Mystery Box, Reference Recordings -HDCD SAMPLER VOL
II, RR-53 - MIKE GARSON: Oxnard Sessions Vol. II, RR-59 - DICK HYMAN: From the Age of
Swing, RR-61 - TURTLE CREEK CHORALE: Postcards, RR-62 - DALLAS WIND SYMPHONY / FREDERICK
FENNELL: Beachcomber, Arnold for Band, RR-63 - CLARK TERRY / FRANK WESS / DePAUL UNIV. BIG
BAND: Big Band Basie, RR-66 - DALLAS WIND SYMPHONY / JERRY JUNKIN: Arnold for Band
Non-HDCD:
Airto Moreira and the Gods of Jazz - Killer Bees, Pat Coil - Schemes and Dreams, Janis Ian
- Between the Lines, Rebecca Pidgeon - The New York Girls' Club, The Raven, Michael Ruff -
Speaking in Melodies, Neil Young - Landing on Water, Clifford Brown - Live at Ethell's
Daniel Long
� Copyright 1997 Secrets of Home Theater & High Fidelity
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