Digital Interconnect Questions


I've always used inexpensive consumer grade digital cables of the $25 - $40 variety from Circus City, GoofGuys, etc. I'm talking about the 75ohm coaxial cable for attaching CD transport to DAC. Is there a significant difference in sound quality with higher-end digital interconnects? I've always been skeptical of over priced cables, especially the digital interconnect. I'm not seeking a debate but would like to know if anyone can actually hear a SIGNIFICANT difference. Thanks.
abecollins
In my very limited experience, yes, differences can be heard (in a good, highly resolving system, of course). I just recently bought my first outboard DAC, a Theta DSPro Basic IIIa, to feed from my Adcom player. I went to a dealer and picked up two interconnects, a $60 Vampire, and one made by a previously unheard-of (by me) local company (VA) called Empirical Design, at $150 (FYI, they are supposedly run by a guy who used work for Goldmund, and the story is that this IC is basically the same as one they used to market for about $450). Both are coaxially shielded, 75ohm cables at 1m, the Vampire being silver-plated OFC copper with PE insulation in an average-diameter soft PVC jacket, and of course using their own connectors; the Empirical Design employs "pure" copper conductor and shield in foamed Teflon insulation with a narrow-diameter Teflon jacket, and what appear to be Tiff RCA's. If I was hoping to be able to return the cable that would save me $90, I was disabused of that notion within one hour's burn-in and auditioning. The primary areas of sonic improvement I can point to would have to be treble smoothness, followed by superior soundstage depth and transparency to low-level detail, but the truth is that the costlier wire just gave a presentation that clearly exceeded overall in its naturalness and "organic wholeness", leading to an increase in general believability. The cheaper stuff, while still sounding better with the DAC than the CD player run on its own, seemed more coarse, flat, and mechanical in comparision. (Digital IC performance is said to be highly dependent on the partnering transport and decoder in question, so this result is not to be taken as universal.) I intend to continue with further comparisions (within a reasonable budget) to see what more is possible, and have become curious to check out one of the outboard jitter-reduction devices such as a DIP as well, since my "tranport" isn't in the same league as the processor. In any case, it may not cost anything but your time to experiment (given a helpful dealer), so you should definitely try an upgrade and stop wondering. Good luck!
My Acoustic Zen MC2 comes the closest to my analogue cables after comparing at least 7 or 8 different brands. The clear, if not profound difference in cables has helped make my home theater listening "even better than the real thing". Don't just listen for the immediate differences, listen for 2 hours at a time for a few days. Harshness and listener fatigue reveal themselves over time.
I have to agree with zugswang. I have tried various links(jenalabs,stealth,tributaries)and the canare cable is great and inexpensive(LV77S) Good listening.
Can I hear "significant" differences in digital cables? Short answer: yes, with certain cables, on certain equipment, in certain configurations, for certain purposes, with certain musical material, after a certain break-in time. You should keep in mind that, unlike its counterpart, the transmitted bandwidth of digital audio signals occurs in the megaherz range, and has more in common with video signals than with lower-bandwidth analog audio range. This means that cable impedance must be more closely matched and that deviations from 75 Ohm (for S/PDIF) and 110 Ohm (for AES/EBU) will seriously deform digital waveforms. If you have no idea what a deformed digital wave sounds like, use a Y-cord to split a digital signal between two recorders and listen to the result.
In addition, the best cable manufacturers design digital cables to avoid another common cause of errors: reflections in the signal path. Along with impedance mismatch, reflections can cause a decrease in rise time, and a misinterpretation of the actual zero-crossing point of the waveform.
The sonic results of passing a digital signal through an inferior digital cable are as follows: 1.) increased "graininess" (the sound is no longer as smooth), 2.) loss of focus and sharp edges in instrument position; 3.) apparent loss of level, making the listener wanting to turn the level up during soft passages, even though high-level signals are reproduced at proper gain; 4.) spurious (phantom) tones; 5.) added noise and distortion; 6.) loss of low-level resolution. These effects should be audible at all listening volumes. Nevertheless, they are subtle, and some say that they require high-quality digital equipment with audiophile musical material to be audible at all. Other audiophiles go so far as to say that the effects are not audible at all with most recorded music today and that expensive digital cables are a waste of money.
Nevertheless, others claim to hear the differences. To satisfy their qualms, cable manufacturers have started to produce better and/or more expensive digital cables. In the process, some manufacturers have discovered that a superior digital cable is just as difficult to design as a superior analog cable. Careful tests, that should accompany the development of a digital cable, are expensive to carry out, and the exact causes of differences in digital cables has not yet been fully uncovered. Besides the points about impedance and reflection that I have already mentioned, there are some theories that the power supplies of digital components carry a small residual of errors to different stages in digital components due to high-frequency energy dissipation giving rise to logic-induced modulation. These errors can be carried by both digital interconnects and power cables hooked up to digital components. But this is a topic for another day...
If you use several digital devices in a daisy-chain fashion (A/D - digital preamp - digital EQ - D/A - Digital recorder, in whatever configuration), the possible side-effects of poor digital cables become more possible. If you do not use a digital distribution system, then you should probably think about testing different digital cables. No reliable listening test of a S/PDIF cable can be conducted over the weekend, because burn-in time is long. Because of their lower peak-to-peak voltage levels, some S/PDIF cables can take over 1,000 hours playing time before they reveal their true nature; AES/EBU takes less time because of a different configuration. Contrary to the advisability of short analog signal paths, short digital interconnects can give rise to more errors than longer ones. A cable length of 1.5 meters is thought to be the minimum recommendable length by some people, with improvements sometimes achievable with even longer runs, as long as these are not too long (over 100 meters).