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.