I would like to take a stereo signal from the line-out of my stereo (or TV) to the line-in of my PC.
The equipment is in different rooms and the audio cable would be 10 metres. It will be this type:
formatting link
I don't understand the technical side but is 10 metres so long that it might cause audio problems with things like frequency response or voltage/current levels and so on?
Will I need to get some higher specification audio cable to cover that distance? I want to keep cost down.
I have used similar cable for a similar purpose over longer distances with no problems, for general purpose "listening" quality. Buying a higher spec cable is only going to give a very marginal improvement - if you really are interested in quality, you would link digital ports using an optical cable and not use analogue, anyway.
You might get unacceptable noise pickup, you might not. Try. You might also get hum. Sometimes it responds to simply lifting the screen connection at one end, sometimes you need an isolating transformer. Or rather a pair of them.
The cable is most likely just fine. However beware of ground loops and other hazards of running audio over long distances. These have little to do with the cable.
My "trans-workshop cable" is about 8 metres long and works perfectly. It's cheap audio cable (shielded of course).
The equipment on both ends is powered from the same electrical circuit and I don't have ground loop problems. You would have ground loop problems if the equipment were powered from different circuits. I gather that you are in the UK (hence "ring" wiring structure, which I like, instead of the American daisychain) and that everything is in the same room. It should work fine.
So how does house wiring work in the UK? Is there more than one grounding ("earthing") point? And how is this better?
(Here, the Merkin practice is to ground the "service panel"--the box where the big wires come into the house--to a single ground rod, with everything running downstream from that.)
By the way, this brings up a strange experience I had recently doing some wiring. I was working for a guy who owns two houses right next to each other, and he wanted to run a cable TV connection from one house to the other. I was about to connect the cable in the attic of the house that was the source of the signal when I got a little tingle. After grabbing a VOM, it turned out that there was about a 20 volt difference between the two cable grounds.
Was this due to power line potential differences, or to cable signal potential differences, or something else? The cable guys do their own grounding outside, and I don't think they put in any bonds to the electric service ground. In any case, the whole project was abandoned then and there as a bad idea. (It occurred to me that a cable transformer could have solved the problem, but then so could doing the thing the right way: just getting both houses wired for cable.)
Most likely the two houses weren't on the same phase of the three phase supply to the street. Their two grounds could have been doing very different things voltage-wise. You should always have an isolation transformer in a connection like this.
I seriously doubt that, because then the potential would have been more like 120 volts, right? I think that's grasping at straws: so far as I know, PG&E (local electricity dealer) doesn't even supply 3-phase to residential customers. In fact, not even in come commercial districts. I owned a small business in Berkeley (print shop) until last year, and I remember the previous owner telling me about all the headaches he had in having PG&E put in a 3-phase converter (in an underground vault below the sidewalk outside). So I know that utility lines don't usually carry
3-phase power, except to large industrial customers.
Why would it be 120V? The voltage would depend on how stiff the ground is round your way. As for three phase supply, no, individual domestic properties generally don't get that, but streets certainly do - that is the efficient way to deliver power.
What they tend to do is supply the area with a three phase line at around 11Kv and transform that down and then supply house number one with phase one, house two with phase two, three with phase three, four with phase one, five with phase two, house six with phase three and so on. Its called load balancing between the phases...
Not in the parts of the USA where I have lived (up and down the west coast). They break up the 3 phases back at the main road and supply only one of the phases to each street (or 2-3 streets depending on the load) It is not economical to run all
3 phases along residential (or even small business) areas.
As I understand it, the British ring system is to wire the outlets in a room in a ring so that each of them has two parallel paths to the point where power enters the room. As a result, a single high-resistance connection anywhere in the ring will have almost no effect. That should do a more reliable job of tying together all the ground connections for the different pieces of equipment.
So what do they do when somebody asks for three phase supply? Even a reasonably small business here in the UK might well do that if their power needs are significant. The power companies here actually prefer to supply businesses that way, particularly if they are also careful about their power factor correction.
Or are zoning laws in the States such that it is not possible to set up a business in an otherwise residential area?
Almost right. The ring actually goes right back to the breaker box, which is always located where the power enters the house. But the effect is the same.
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