Untangling the cables of time...
It’s a good time to clean out, the summer break. I might have a go at my cables. The missus will laugh to hear that, of course. Once a year or so she finds me in the basement buried under one monumental tangle, surrounded by plastic storage containers. Some of the cables go back 20 years or more, to band days — guitar leads and mike extension cables which would probably crumble into piles of distressed rubber if actually excited by insertion into something. There are great lengths of cable with no plugs at all, which have long stood ready and eager for termination in the pluggery sense, but which may, I fear, be terminated in the Council Clean-up sense this time around.
And what’s this? A reverse-wired five-pin DIN cable with a paper label obviously written by my father. What could that be for? I’d better hang on to it.
One thing is interesting here (well, you know, if you like cables), and that’s the changing size of my different cable collections. You’re dying to know, I can tell. OK, so the video-cable bags (purple carriers, if I can get them) seem to have shrunk of late, perhaps because in today’s video world, a handful of HDMI connections have displaced the glory days when we’d have dozens of parallel composite, component, SCART and S-Video cables flowing gracefully in and out of our multichannel receivers. All those colours, it was beautiful. Here, look at the rainbow ribbons on these SCART-to-flying-RCA adaptors — always handy for plugging up old European kit brought over from the UK. Yes, better keep those as well.
The hi-fi cable collection is holding steady — lots of out-of-the-box phono-to-phono cheapies; very few high-quality ones spare these days. I never seem to have any digital or optical audio cables at all, except when they arrive temporarily with review equipment. (Reviewer’s Code of Honour Article 5: Put the cables back in the box for the next guy.)
In any case, digital audio in our home reaches the hi-fi via USB1. That container — the one for computer cables — is positively groaning with bulky display connectors, micro-USB and mini-USB cables. And masses of Ethernet cable. I can’t believe how much of the stuff I use. (I have Ethernet switches on two sides of the lounge now. My mind is running riot at the idea of specifying the electrics for a new attic room.)
So video cable stocks are down, computer cables definitely on the up. In a thoroughly modern replay system — from the internet, to the computer, to a media player, or Etherneted to the TV — it’s computer cables all the way.
Cable fans will be wondering why I have made no mention yet of mains cables, nor of the hilarious hyper-tangly world of telecom cables. Not to mention the anecdotes I had hoped to relate about a bag of generic power supplies I haven’t reconciled with products too lowly to brand-label their mains adaptors.
Another time, as sadly I seem to have run out of space for this issue, having degenerated into a tangle of footnotes2.
Cheers,
Jez Ford, Editor
www.twitter.com/jezford
Geare: Januaru/February 2010
1: With regard to computer audio via DAC, there’s debate brewing about USB vs the more hi-fi S/PDIF as used in optical or RCA electrical connections (it stands for Sony/Philips Digital Interconnect Format). Strange, really, because USB would seem obviously the easier choice for computers, with no obvious audio flaw — USB data transfer is a 100%-accurate process, as I understand it, and the data is reclocked on receipt, so it’s hard to see what issues might exist.
The most common issue raised is ‘timing’. The timing argument goes like this. We know that the data received is
100% accurate in that we get the correct value for each bit of information: 0 1 0 1 0 1 1 0. But if timing is somehow affected, perhaps by a long length of poor cable, some of those ‘1’s may be slightly shorter than others, or for a while they might ALL be shorter than they should, so that the density of the data is reduced, or raised, or whatever. If immediately translated to the analogue domain (to drive speakers), this would translate as small-scale power fluctuations — noise.
But USB is re-clocked, by definition and design; it gets the numbers and rebuilds them with shiny new ‘1’s and ‘0’s, as perfectly chopped as it can manage. Could you have a timing error so severe as to cause a data error, an actual transition from 0 to 1? Yes, but only in an appallingly designed system (a system that wouldn’t work, indeed).
S/PDIF transmits its own clock, so a master clock can be ‘synced’ between components.3 But if receiver chips simply lock on and output a signal based on this master clock, then, yes, timing errors could indeed appear. In fact I gather “any decent DAC design” re-clocks S/PDIF as well.4
So I think we’ll go USB on this one, or at least agnostic in audiophile terms. Chris Connaker of Computer Audiophile researched and, more importantly, listened extensively to USB vs SPDIF and (on his system) he couldn’t express a preference either way.
2: Nothing wrong with footnotes.
3: This idea of ‘passing the clock’ down the digital chain makes sense only if no reclocking occurs; it prevents a build-up of jitter by relying on a master clock used through the chain, although this synchronous transmission could make the signal prone to timing errors. The master clock can be tuned with great accuracy. Nevertheless the only ideal master clock would precisely follow that of the original mastering equipment at the time of recording — something never attempted, as far as I know.
4: I await correction on this. But if true, then only two points in the chain require high attention to clock accuracy — the recording/mastering, and the final pre-analogue link in the reproduction chain.
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