Audio & video cabling

Feb 14, 2004 9 Replies
2 questions now that I have my audio cabling set up so nicely thanks to all your advice:

i) if I want to send composite video (the sort that normally comes out of a single yellow phono socket) from a DVD player to a monitor, about



10-15 meters along a cable, what sort of cable should I use? I have some runs of Maplin's XR21X. Is that likely to work OK, or will I need some specific coax (I don't either the player or the monitor yet, otherwise I could just try it out!).

ii) I'd like to set up some audio switches near the computer. The basic idea is this:



Input 1: Line in from DVD Player -| | Switch 1 - Output 1 (Computer Speakers) | Input 2: Computer Audio Out ------| | Switch 2 - Output 2 (Line Out to Amplifier) | Input 3: DAB Radio ---------------|



This might work with 2 rocker switches (the point is that Output 1 is either Input 1 or Input 2; Output 2 is either Input 2 or Input 3).



Alternatively if I had 2 x 3(or more)-position rotary switches, I could select any of the inputs for either of the outputs. In both cases the switch would have to switch all four lines that come with a standard pair of phono plus.



It looks as though 2x Maplin's CN47B would do the trick. But it would be a bit wasteful of space and require a load of splitters (as the inputs to both boxes would be the same). Any inspiration on how I might go about making my own custom switch; (or, even better, someone who already sells something nearer my requirements than the CN47B).



Many thanks in advance



James


"James" wrote | i) if I want to send composite video (the sort that normally comes out | of a single yellow phono socket) from a DVD player to a monitor, about | 10-15 meters along a cable, what sort of cable should I use? I have | some runs of Maplin's XR21X. Is that likely to work OK, or will I | need some specific coax (I don't either the player or the monitor yet, | otherwise I could just try it out!).

XR21X, for those who don't have Maplin stock codes engraved in their memory, is some figure-8 single-core screened audio cable.

You can try it, especially if it is already in place, as there's a good chance it will work, but you may find you get a poor picture and need proper video cable. Any 75ohm video cable should do, you could probably even use 'brown low-loss' TV aerial cable, but most of that isn't fit for TV aerials.

For any TV/video use, CT100 or equivalent satellite cable is usually recommended. Maplin's price is 99p/m for XS16S, you should be able to find it for less. Even Maplin half the price per m for a 100m reel. Not sure how well it would fit into a phono plug thought.

Or you could use XS41U which is actually sold for making up composite video SCART cables, so it should be suitable, and it's also 99p a m and would carry an audio feed too.

formatting link
| ii) I'd like to set up some audio switches near the computer. The | basic idea is this: | | Input 1: Line in from DVD Player ^^^ out

| This might work with 2 rocker switches (the point is that Output 1 | is either Input 1 or Input 2; Output 2 is either Input 2 or Input 3). | Alternatively if I had 2 x 3(or more)-position rotary switches, I | could select any of the inputs for either of the outputs. In both | cases the switch would have to switch all four lines that come with a | standard pair of phono plus.

You have to watch that you don't connect the outputs of two devices together into one input. An output can feed multiple inputs, but you shouldn't shove several different source outputs into the same input.

| It looks as though 2x Maplin's CN47B would do the trick.

A 4-way stereo audio switch box.

Have a look at L62AB a 4 input 2 output audio/video selector. "Either output can independently select any input. A built-in apmpliier compensates for insertion losses" - this is probably for the video only and the thing can probably be used without power for audio. Neater and, at 19.99, cheaper than

2 x CN47B at 12.99 each.

formatting link

I have a 25m run of a similar cable for a composite video link and it works fine.

Take a look at switching it electronically....

Analogue switching IC's are very easy to use, would be much cheaper than multi pole mechanical switches and be more reliable.

I use RG58 (a 50 ohm co-ax often used for VHF radio mic aerial feeds) for this sort of thing - it's cheap and will fit a phono plug. I don't think the nominal impedance of the cable matters much over short runs at video frequencies, although the capacitance of a typical audio cable might just.

What for?

F*ck off, Harry.

Wish you lot would, selfish tossers.

Is that for your HOT webcam, Harold? Do you have a website that we can look at?

I do *not* want to look at his awning.

It's huge!

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required