I’m currently looking to run a stereo audio line from my PC’s sound card to my TV. At the PC end I’ve got a female 1/8" stereo connector, at the TV end I’ve got dual RCA jacks. The run will be about 50’, as it has to run along the edge of the wall to keep reasonably presentable.
Any suggestions on what I should use? I’ve been told to avoid using a 50’ RCA cable, as the noise on it could be a problem. I’ve considered possibly using two lengths of coaxial cable, but finding connectors for it could be a problem, especially going from two coax cables to a single 1/8" stereo connector.
Also, while we’re at it, I’ve got a 50’ length of S-Video cable that I intend to use for the same setup. It seems to give me a pretty decent picture, but are there any suggestions of something that may be better?
Please note that price is of paramount concern in this little project.
The main thing with the audio wires is to use thick wire–particularly if the wire won’t ever be moved around much. Wire resistance goes up as the wire gets thinner, so use really thick wire. Like, 10-12-14 gauge wire–get the thickest 2-conductor wire you can easily find that is meant for replacing appliance cords. (wire size “thickens” as the number goes down, and most single-bulb lights/small appliances use 18 gauge wire. Most cheap speaker wire is 24 gauge) The main difference between “cheap” and “more expensive” regular appliance cord wires is that the cheaper stuff will discolor and the insulation will crack off sooner then the expensive will. Direct exposure to sunlight also increases this problem–but you can go to any large hardware store and buy whatever they got.
If the S-video cable works as-is, just use it. With video there are additional RF concerns and it is wisest to simply use real,actual TV-signal cable rather than try to make something yourself (and wonder why the TV picture looks so lousy!).
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DougC: I would agree with you if speaker cables were being run. But I believe the OP is running line-level audio cables.
Melraidin: Assuming you want to run line-level cables, resistance is not an issue. This is because the input impedance on your TV is fairly high. My advice is to run cables that minimize noise and capacitance. I would not suggest coax, as it comes up short in both departments. Instead, I would run “twisted pair in a shield.” For the frequencies you’re dealing with, cable impedance would not be much of an issue, so just buy the cheapest stuff you can find. (Also keep in mind that “twisted pair in a shield” cable is especially beneficial in “balanced” systems. I’m not sure if your setup is balanced. Even if it isn’t, you can still benefit from its low capacitance.) As far as the S-video cable goes, I believe it is already balanced. So just make sure the cable is shielded.
Crafterman, I tried this once with my sound card. I couldn`t even get a good signal to my reciever about 30 feet away. Some guy at the local electronics store told me that with a LL output from my soundcard, that I could only, realistically, go about six feet. The reciever had to be very close to the machine. I did get a signal at the thirty feet, it was just very quiet and hissy.
I don’t think what you’re suggesting is a good idea, Crafter_Man. The source and the sink of the audio are both unbalanced, i.e., one side is grounded. Running a shielded twisted pair without transformers at both ends doesn’t net you any gain over just using a single shielded cable (which of course, is what coax is). The S-video is also unbalanced, and runs in coax.
I’m using a 15 m length of ordinary cheap cable (single shielded x 2, with RCA plugs at either end) for one particular run at my place. Works fine.
You’re correct, Desmostylus. And I made a mistake in my first post: Coax typically has less distributed capacitance when compared to twisted pair.
But even at 50 feet, I kinda wonder if line impedance, capacitance, etc. should even be considered at audio frequencies. (I have used twisted pair for unbalanced audio with no problem.) If these characteristics do not matter, then we could ask the following question: which offers better noise immunity? I am of the opinion that (in general) twisted pair in a shield is better than coax in this respect, though it may not make much of a difference for an unbalanced application. Of course, he could always install a Balun on each end and use Cat5 cable.
I used to run a line level signal between two floors in Pittsburgh.
I first tried a pair of coax cables, and didn’t like it at all (30’ run). I did much better going to a car audio place, and getting a length of interconnect cable from them and adding my own connectors on each end. Cars are pretty noisy electrically, so the shops usually carry well shielded stuff.
Have you looked at the 2.4Ghz or 802.11 A/V transmitters and going wireless? There’s ones that carry both stereo and video signals. I know it’s a bit more expensive, but might be nice if there’s no real good cable route.
