Despite the axiom of “bits is bits”, does various brands and makes of digital interconnect cables have their own “distinctive” sound when subjected to empirical listening tests?
By: Ringo Bones
Even though “civilians” might balk at us audiophiles for
what we have known first hand since being fortunate enough to afford our very
own two-box CD player / DAC combo that we can toy around with various makes and
models of digital interconnect cables, each of our very own empirical testing
experiences had revealed that digital interconnect cables don’t sound the same
– at least to most of us hardened audiophiles. Compared to vinyl LP playback
cartridges of old, the differences between various make s and models – and
especially price ranges – of various digital interconnect cables may be subtle,
but nonetheless, a difference between them do exist. But why is it so, after
all, digital ones and zeroes as in bits is bits, right?
If only digital telecommunications engineering were as
simple as bits is bits in actual practice, but its not. Let’s start at the
digital data read optic assembly of a typical CD / DVD or universal digital
disc player when it reads a typical CD or other digital audio playback disc, in
truth the optical assembly doesn’t output a digital data signal that can
readily be deciphered by the player’s digital to analog converter – or the
outboard DAC – as streams of ones and zeroes. In reality, it is composed of a
rather roughly square wave shaped but actually complex radio-frequency analog
waveform that had to be deciphered into digital code that would later be
converted into an analog music signal. The fidelity of this RF signal is very
dependent not just on the transport and its support, but also – in the case of
two box player/outboard DAC systems – the shielding and electrical characteristics
of the digital interconnect cable in use.
During the 1990s, I was fortunate enough to buy second hand
bargain samples of Kimber’s Illuminati D-30 digital interconnect cable which I
readily compared head-to-head with the cable, I was using on my system back
then (even now!) the Monster Cable Interlink Datalink 100. In short, the sound
of the two is quite different from each other – the Illuminati DV-30 is rhythmically
fast yet tonally threadbare when auditioned in my Audio Alchemy based two box
CD rig. While the Monster Cable is tonally full yet somewhat plodding in the
rhythm and pace department compared to the Illuminati at almost twice the
price.
Sadly, the only digital interconnect cable that allows me to
have my cake and eat it two as a perfect blend of both Kimber Illuminati DV-30
and the Monster Cable Interlink Datalink 100’s strengths was the XLO Limited
Edition The Digital Interconnect which I managed to borrow from a well-off
fellow audiophile. But with the 0.5 meter RCA terminated set at 750 US dollars
when new, it was too rich for my blood. Fortunately a few days ago, my
audio-buddy lent it to me in a more or less permanent basis cause he was “too
busy” to listen to his hi-fi rig for more than three weekends a month.
Though Stereophile magazine reviewer Jonathan Scull was spot
on – journalism wise – in praising it when he reviewed the XLO Limited Edition
The Digital Interconnect back in the August 1998 issue of Stereophile magazine.
Cable guru Roger Skoff’s iconic late 1990s creation just can’t be beat that
uses proprietary Teflon AF insulation – a licensed product for special military
and aerospace applications that sells for more than 7,000 US dollars per
kilogram – virtually as expensive as pure gold.
In real world telecommunications engineering terms, the
impact of different cables on the transmission of digital data might seem
minimal in practice but they can be quite audible. The digital data representing
the music signal need not be directly corrupted in a manner that would have a
typical personal computer program to crash, for example, because the analogy
between personal computer operating system data integrity and transmission
rates only holds so far for digital audio.
For example, differences in the construction of a digital
audio cable will affect both screening and characteristic impedance which, in
turn, influence both the interference and the “shape” of the recovered data
waveform, respectively. In all this respects, it is important to appreciate
that digital data will eventually be converted into analog signals and that any
modification – in the form of jitter – or RF noise interference will have an
impact on the player’s analog circuitry and the music that flows. Remember,
data integrity of the operating system’s ones and zeros may be everything to a
typical personal computer, but in digital audio – especially the jitter
infested Redbook spec 16-Bit 44.1-KHz sampled digital audio – data integrity of
the bitstream is just the beginning.
