Home |
Search |
Today's Posts |
#1
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
I am in the UK.
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: http://www.maplin.co.uk/images/full/130i0.jpg 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. |
#2
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
Andy wrote:
I am in the UK. 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: http://www.maplin.co.uk/images/full/130i0.jpg 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. -- Sue |
#3
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
On Tue, 18 Apr 2006 22:35:53 +0100, Andy wrote:
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: http://www.maplin.co.uk/images/full/130i0.jpg 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. 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. What's the link for? |
#4
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
"Andy" wrote ...
I am in the UK. 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: http://www.maplin.co.uk/images/full/130i0.jpg 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. 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. |
#5
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
Will I need to get some higher specification audio cable to cover that
distance? I want to keep cost down. 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. Expanding on that a little: 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. |
#6
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
mc spake thus:
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.) -- Pierre, mon ami. Jetez encore un Scientologiste dans le baquet d'acide. - from a posting in alt.religion.scientology titled "France recommends dissolving Scientologists" |
#7
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
David Nebenzahl wrote:
mc spake thus: 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. Mc doesn't understand ground loops. You can get them between two boxes plugged into the same double socket. Your tingle was because your equipment is not grounded, and is perfectly normal. -- Eiron No good deed ever goes unpunished. |
#8
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
Eiron spake thus:
David Nebenzahl wrote: mc spake thus: 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. Mc doesn't understand ground loops. You can get them between two boxes plugged into the same double socket. Your tingle was because your equipment is not grounded, and is perfectly normal. No, my tingle was because I was holding two cables strung between two different houses, each grounded at its end. Doesn't seem normal at all to me. -- Pierre, mon ami. Jetez encore un Scientologiste dans le baquet d'acide. - from a posting in alt.religion.scientology titled "France recommends dissolving Scientologists" |
#9
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
On Tue, 18 Apr 2006 23:32:56 -0700, David Nebenzahl
wrote: Eiron spake thus: David Nebenzahl wrote: mc spake thus: 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. Mc doesn't understand ground loops. You can get them between two boxes plugged into the same double socket. Your tingle was because your equipment is not grounded, and is perfectly normal. No, my tingle was because I was holding two cables strung between two different houses, each grounded at its end. Doesn't seem normal at all to me. 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. d -- Pearce Consulting http://www.pearce.uk.com |
#10
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
Don Pearce spake thus:
On Tue, 18 Apr 2006 23:32:56 -0700, David Nebenzahl wrote: Eiron spake thus: David Nebenzahl wrote: mc spake thus: 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. Mc doesn't understand ground loops. You can get them between two boxes plugged into the same double socket. Your tingle was because your equipment is not grounded, and is perfectly normal. No, my tingle was because I was holding two cables strung between two different houses, each grounded at its end. Doesn't seem normal at all to me. 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. -- Pierre, mon ami. Jetez encore un Scientologiste dans le baquet d'acide. - from a posting in alt.religion.scientology titled "France recommends dissolving Scientologists" |
#11
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
On Tue, 18 Apr 2006 23:49:28 -0700, David Nebenzahl
wrote: Don Pearce spake thus: On Tue, 18 Apr 2006 23:32:56 -0700, David Nebenzahl wrote: Eiron spake thus: David Nebenzahl wrote: mc spake thus: 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. Mc doesn't understand ground loops. You can get them between two boxes plugged into the same double socket. Your tingle was because your equipment is not grounded, and is perfectly normal. No, my tingle was because I was holding two cables strung between two different houses, each grounded at its end. Doesn't seem normal at all to me. 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. Could be different where you are,of course. d -- Pearce Consulting http://www.pearce.uk.com |
#12
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
On Tue, 18 Apr 2006 23:49:28 -0700, David Nebenzahl
wrote: 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. There'll probably be 3 phases in the street. houses, or groups of houses will be allocated a single phase. |
#13
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
I
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. 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... -- Tony Sayer |
#14
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
"David Nebenzahl" wrote ...
No, my tingle was because I was holding two cables strung between two different houses, each grounded at its end. Doesn't seem normal at all to me. If they were each properly "grounded", you would NOT have seen any voltage differential. BY DEFINITION. (Or else the two houses were on differen planets. :-) |
#15
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
"Laurence Payne" wrote...
There'll probably be 3 phases in the street. houses, or groups of houses will be allocated a single phase. 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. |
#16
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
"Richard Crowley" wrote in message
... "David Nebenzahl" wrote ... No, my tingle was because I was holding two cables strung between two different houses, each grounded at its end. Doesn't seem normal at all to me. If they were each properly "grounded", you would NOT have seen any voltage differential. BY DEFINITION. I would almost bet that at least one of them wasn't really grounded (to the earth). Second choice is that high voltage is being conducted directly into the earth from some kind of unintended connection. A bad thing. |
#17
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
"David Nebenzahl" wrote in message .com... mc spake thus: 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? 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. |
#18
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
"Eiron" wrote in message
... Mc doesn't understand ground loops. You can get them between two boxes plugged into the same double socket. Two boxes with 3-wire plugs? Could you elaborate? I thought a ground loop was due to difference in potential of the ground connections of 2 different pieces of equipment. |
#19
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
On Wed, 19 Apr 2006 07:26:25 -0700, "Richard Crowley"
wrote: "Laurence Payne" wrote... There'll probably be 3 phases in the street. houses, or groups of houses will be allocated a single phase. 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. 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? d -- Pearce Consulting http://www.pearce.uk.com |
#20
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
On Wed, 19 Apr 2006 10:33:13 -0400, "mc"
wrote: "David Nebenzahl" wrote in message s.com... mc spake thus: 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? 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. 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. d -- Pearce Consulting http://www.pearce.uk.com |
#21
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
"Andy" wrote in message ... I am in the UK. 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: http://www.maplin.co.uk/images/full/130i0.jpg 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 am using the exact same cable from Maplin, this is to go from my computer to my stereo amp. I would estimate it to be 10m-15m in length and I've had no problems with noise. sQuick.. |
#22
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
On 19 Apr 2006, wrote:
mc spake thus: 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. Mc doesn't understand ground loops. You can get them between two boxes plugged into the same double socket. Your tingle was because your equipment is not grounded, and is perfectly normal. Does your "perfectly normal" mean: "there is no fault and no danger (until the ground is actually needed and then will be a danger)" |
#23
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
On 19 Apr 2006, wrote:
"Andy" wrote in message ... I am in the UK. 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: http://www.maplin.co.uk/images/full/130i0.jpg 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 am using the exact same cable from Maplin, this is to go from my computer to my stereo amp. I would estimate it to be 10m-15m in length and I've had no problems with noise. sQuick.. Thanks to you and everyone else for the feedback. Seems it is less of a problem than i was anticipating. Actually my cable is not exactly the Maplin one I illustarted but a very similar one. |
#24
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
"mc" wrote:
"Eiron" wrote in message ... Mc doesn't understand ground loops. You can get them between two boxes plugged into the same double socket. Two boxes with 3-wire plugs? Could you elaborate? I thought a ground loop was due to difference in potential of the ground connections of 2 different pieces of equipment. A "ground loop" is caused by having a common ground path for two different signals. Current from each signal causes a voltage drop, due to Ohmic losses, across the ground path for both circuits. The effect is that each circuit affects the signal of the other. Typically if one of those signals is 60 Hz power and the other is something in the audio range, the audio signal will then have a 60 Hz "buzz" on it. Obviously, if the only ground path is through a common 3-wire socket, yes it is possible for two boxes to have a ground loop. -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
#25
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
"Richard Crowley" wrote:
"David Nebenzahl" wrote ... No, my tingle was because I was holding two cables strung between two different houses, each grounded at its end. Doesn't seem normal at all to me. If they were each properly "grounded", you would NOT have seen any voltage differential. BY DEFINITION. (Or else the two houses were on differen planets. :-) That is not true. Granted that the 20 Volt differential he mentions in another article is high (for a residential area), it is not at all uncommon. What is uncommon though, is a person who can actually feel 20 Volts! -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
#26
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
"mc" wrote:
"Richard Crowley" wrote in message ... "David Nebenzahl" wrote ... No, my tingle was because I was holding two cables strung between two different houses, each grounded at its end. Doesn't seem normal at all to me. If they were each properly "grounded", you would NOT have seen any voltage differential. BY DEFINITION. I would almost bet that at least one of them wasn't really grounded (to the earth). Then there would have been no differential, and hence no voltage and no tingling... ;-) Second choice is that high voltage is being conducted directly into the earth from some kind of unintended connection. A bad thing. Not a bad thing, just a rather common thing in many industrial areas. -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
#28
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
(Don Pearce) wrote:
On Wed, 19 Apr 2006 07:26:25 -0700, "Richard Crowley" wrote: "Laurence Payne" wrote... There'll probably be 3 phases in the street. houses, or groups of houses will be allocated a single phase. 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. So what do they do when somebody asks for three phase supply? Even a The above does describe typical residential power distributionn. However, anywhere that industrial power (i.e., 3 phase) is available, there will in fact be all three phases available... 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. Same in the US. Or are zoning laws in the States such that it is not possible to set up a business in an otherwise residential area? That might be, might not be... it would depend on local laws. -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
#29
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
Don Pearce spake thus:
On Wed, 19 Apr 2006 07:26:25 -0700, "Richard Crowley" wrote: "Laurence Payne" wrote... There'll probably be 3 phases in the street. houses, or groups of houses will be allocated a single phase. 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. 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. Reread my earlier post above. In it I described the situation where a business I once owned needed to have a power converter installed for 3-phase. This was in Berkeley, in a commercial district, not a residential one, and I think it's pretty typical of the Bay Area in general, probably the urban U.S for that matter. The power companies don't supply 3-phase power even to commercial areas; if someone needs it, they put in a converter. (We had a printing press that required it.) Most commercial businesses don't need 3-phase power. Large industrial customers do. I think the converters can be shared, so if a couple or a few neighboring businesses need 3-phase power, they can all use the one converter. -- Pierre, mon ami. Jetez encore un Scientologiste dans le baquet d'acide. - from a posting in alt.religion.scientology titled "France recommends dissolving Scientologists" |
#30
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
On Wed, 19 Apr 2006 11:34:12 -0700, David Nebenzahl
wrote: Don Pearce spake thus: On Wed, 19 Apr 2006 07:26:25 -0700, "Richard Crowley" wrote: "Laurence Payne" wrote... There'll probably be 3 phases in the street. houses, or groups of houses will be allocated a single phase. 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. 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. Reread my earlier post above. In it I described the situation where a business I once owned needed to have a power converter installed for 3-phase. This was in Berkeley, in a commercial district, not a residential one, and I think it's pretty typical of the Bay Area in general, probably the urban U.S for that matter. The power companies don't supply 3-phase power even to commercial areas; if someone needs it, they put in a converter. (We had a printing press that required it.) Most commercial businesses don't need 3-phase power. Large industrial customers do. I think the converters can be shared, so if a couple or a few neighboring businesses need 3-phase power, they can all use the one converter. I'm surprised. Just down the road from me there is a small engineering company - they have a couple of mills, a few lathes and assorted other machine tools. The power company didn't even ask - they just got three phase, straight from the street outside. d -- Pearce Consulting http://www.pearce.uk.com |
#31
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
(Don Pearce) wrote:
On Wed, 19 Apr 2006 09:03:21 -0800, (Floyd L. Davidson) wrote: "mc" wrote: "Eiron" wrote in message ... Mc doesn't understand ground loops. You can get them between two boxes plugged into the same double socket. Two boxes with 3-wire plugs? Could you elaborate? I thought a ground loop was due to difference in potential of the ground connections of 2 different pieces of equipment. A "ground loop" is caused by having a common ground path for two different signals. Current from each signal causes a voltage drop, due to Ohmic losses, across the ground path for both circuits. The effect is that each circuit affects the signal of the other. Typically if one of those signals is 60 Hz power and the other is something in the audio range, the audio signal will then have a 60 Hz "buzz" on it. Obviously, if the only ground path is through a common 3-wire socket, yes it is possible for two boxes to have a ground loop. You got this backwards. Actually, what I said was *precisely* correct. A ground loop is caused by having two ground paths for a single signal wire. Your language is a mess, but what you just said is *exactly* the same thing. One wire is a common path... A hum signal is induced into the signal wire by means of a hum current flowing round that ground loop. Wrong. There is no loop involved. It is current flowing on the *common* portion that causes interaction. That current can be generated in either of two ways - a simple potential difference between the two grounds, or alternatively magnetic induction into the loop; generally the first will generate the bigger signal. Get a book or two... and study what happens. Try drawing a diagram of what you think is happening! -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
#32
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
On Wed, 19 Apr 2006 11:23:24 -0800, (Floyd L.
Davidson) wrote: (Don Pearce) wrote: On Wed, 19 Apr 2006 09:03:21 -0800, (Floyd L. Davidson) wrote: "mc" wrote: "Eiron" wrote in message ... Mc doesn't understand ground loops. You can get them between two boxes plugged into the same double socket. Two boxes with 3-wire plugs? Could you elaborate? I thought a ground loop was due to difference in potential of the ground connections of 2 different pieces of equipment. A "ground loop" is caused by having a common ground path for two different signals. Current from each signal causes a voltage drop, due to Ohmic losses, across the ground path for both circuits. The effect is that each circuit affects the signal of the other. Typically if one of those signals is 60 Hz power and the other is something in the audio range, the audio signal will then have a 60 Hz "buzz" on it. Obviously, if the only ground path is through a common 3-wire socket, yes it is possible for two boxes to have a ground loop. You got this backwards. Actually, what I said was *precisely* correct. Nonsense - you claim one ground path and two signals. It is one signal and two ground paths - it is those two ground paths that form the ground loop. A ground loop is caused by having two ground paths for a single signal wire. Your language is a mess, but what you just said is *exactly* the same thing. One wire is a common path... No, my language is just fine, and it is the exact opposite of what you said. A hum signal is induced into the signal wire by means of a hum current flowing round that ground loop. Wrong. There is no loop involved. It is current flowing on the *common* portion that causes interaction. There is a loop involved. That is why it is called a ground loop. The loop is necessary for the current to flow round and generate the emf that appears on the signal wire. That current can be generated in either of two ways - a simple potential difference between the two grounds, or alternatively magnetic induction into the loop; generally the first will generate the bigger signal. Get a book or two... and study what happens. Try drawing a diagram of what you think is happening! Thank you, I have designed a great deal of high precision measuring equipment and I know exactly what signal paths are present in a ground loop. And they aren't what you claim. d -- Pearce Consulting http://www.pearce.uk.com |
#33
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
David Nebenzahl wrote:
Don Pearce spake thus: On Wed, 19 Apr 2006 07:26:25 -0700, "Richard Crowley" wrote: "Laurence Payne" wrote... There'll probably be 3 phases in the street. houses, or groups of houses will be allocated a single phase. 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. 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. Reread my earlier post above. In it I described the situation where a business I once owned needed to have a power converter installed for 3-phase. This was in Berkeley, in a commercial district, not a residential one, and I think it's pretty typical of the Bay Area in general, probably the urban U.S for that matter. The power companies don't supply 3-phase power even to commercial areas; if someone needs it, they put in a converter. (We had a printing press that required it.) Most commercial businesses don't need 3-phase power. Large industrial customers do. I think the converters can be shared, so if a couple or a few neighboring businesses need 3-phase power, they can all use the one converter. What is a "converter"? I've never heard of anything described that way. Virtually all power is generated as 3-phase... What you actually get merely depends on what the transformer arrangement is. Single phase residential power is nothing other than one phase from a 3 phase distribution system. All that is required to have 3 phase power is *more wires*! -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
#34
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
(Don Pearce) wrote:
On Wed, 19 Apr 2006 11:23:24 -0800, (Floyd L. Davidson) wrote: Actually, what I said was *precisely* correct. Nonsense - you claim one ground path and two signals. It is one signal and two ground paths - it is those two ground paths that form the ground loop. And I have it *precisely* correct. (Hint: I'm not guessing.) If there were only one signal... what problem would there be???? The trouble is that one signal causes interference with another. It does that because they share a common path. Ohmic losses across that conductor affect *both* signals, even when caused by only one of them. Bingo, that *is* the problem. A ground loop is caused by having two ground paths for a single signal wire. Your language is a mess, but what you just said is *exactly* the same thing. One wire is a common path... No, my language is just fine, and it is the exact opposite of what you said. Two ground paths and one wire... does *not* make sense. Signals have paths. Those paths can be wires. You can't have two paths in one wire... But the common "ground loop" is indeed caused by grounding a single conductor at two points. That provides a common path through the single wire... for *two* signals. One is the "desired" signal, and the other is a current between the two ground points. A hum signal is induced into the signal wire by means of a hum current flowing round that ground loop. Wrong. There is no loop involved. It is current flowing on the *common* portion that causes interaction. There is a loop involved. That is why it is called a ground loop. The loop is necessary for the current to flow round and generate the emf that appears on the signal wire. Try drawing a diagram of what you are describing. That current can be generated in either of two ways - a simple potential difference between the two grounds, or alternatively magnetic induction into the loop; generally the first will generate the bigger signal. Get a book or two... and study what happens. Try drawing a diagram of what you think is happening! Thank you, I have designed a great deal of high precision measuring equipment and I know exactly what signal paths are present in a ground loop. And they aren't what you claim. If you do know what it is, you certainly have a problem describing it in terms that make sense. I'll vote for you don't know... -- Floyd L. Davidson http://www.apaflo.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
#35
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
mc wrote:
"Eiron" wrote in message ... Mc doesn't understand ground loops. You can get them between two boxes plugged into the same double socket. Two boxes with 3-wire plugs? Could you elaborate? I thought a ground loop was due to difference in potential of the ground connections of 2 different pieces of equipment. Remember the good old days when everything had a 3-core mains cable? You could get a ground loop just plugging a tape recorder into an amp. The bodger's solution was to disconnect the earth in the mains plug and remember always to connect the audio cable to the amp before connecting the power. Now everything has 2-core power leads so you get tingles. -- Eiron No good deed ever goes unpunished. |
#36
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
On Wed, 19 Apr 2006 11:46:44 -0800, (Floyd L.
Davidson) wrote: (Don Pearce) wrote: On Wed, 19 Apr 2006 11:23:24 -0800, (Floyd L. Davidson) wrote: Actually, what I said was *precisely* correct. Nonsense - you claim one ground path and two signals. It is one signal and two ground paths - it is those two ground paths that form the ground loop. And I have it *precisely* correct. (Hint: I'm not guessing.) If there were only one signal... what problem would there be???? The trouble is that one signal causes interference with another. It does that because they share a common path. Ohmic losses across that conductor affect *both* signals, even when caused by only one of them. Bingo, that *is* the problem. So what are you saying here - that a mono signal can't suffer a ground loop? Stereo is the minimum that can show the problem? You only need one signal. Here's a hint as to where you may be going wrong. Signal is the term used to describe the wanted stuff. The rest isn't signal - it is hum. A ground loop is caused by having two ground paths for a single signal wire. Your language is a mess, but what you just said is *exactly* the same thing. One wire is a common path... No, my language is just fine, and it is the exact opposite of what you said. Two ground paths and one wire... does *not* make sense. Signals have paths. Those paths can be wires. You can't have two paths in one wire... Of course it makes sense. The commonest scenario for two ground paths is that one is the outer of the coax, and the other is a pair of ground wires in the mains leads, meeting at the mains ground. The single signal wire is the inner of the coax. This just isn't that hard to understand. But the common "ground loop" is indeed caused by grounding a single conductor at two points. That provides a common path through the single wire... for *two* signals. One is the "desired" signal, and the other is a current between the two ground points. No it doesn't. It means that the ground is connected via two separate paths - you need those two separate paths to form the loop. A hum signal is induced into the signal wire by means of a hum current flowing round that ground loop. Wrong. There is no loop involved. It is current flowing on the *common* portion that causes interaction. There is a loop involved. That is why it is called a ground loop. The loop is necessary for the current to flow round and generate the emf that appears on the signal wire. Try drawing a diagram of what you are describing. Done. You can find it here http://81.174.169.10/ That current can be generated in either of two ways - a simple potential difference between the two grounds, or alternatively magnetic induction into the loop; generally the first will generate the bigger signal. Get a book or two... and study what happens. Try drawing a diagram of what you think is happening! Thank you, I have designed a great deal of high precision measuring equipment and I know exactly what signal paths are present in a ground loop. And they aren't what you claim. If you do know what it is, you certainly have a problem describing it in terms that make sense. I'll vote for you don't know... No, I think I have described what is going on perfectly - I suspect the confusion is at your end. It may be simply a semantic confusion over what constitutes the signal. d -- Pearce Consulting http://www.pearce.uk.com |
#37
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
Andy wrote:
On 19 Apr 2006, wrote: mc spake thus: 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. Mc doesn't understand ground loops. You can get them between two boxes plugged into the same double socket. Your tingle was because your equipment is not grounded, and is perfectly normal. Does your "perfectly normal" mean: "there is no fault and no danger (until the ground is actually needed and then will be a danger)" No. It's normal and legal to have a load of double-insulated equipment connected together so the signal ground is floating at roughly half mains voltage and can deliver several mA. It's dangerous, in my opinion. In the UK, with 240v mains, and adjacent houses on different phases, you might have 220v between the two cables in the attic. And you can't feel 20v AC unless one end is on your tongue. I just tried it. :-) -- Eiron No good deed ever goes unpunished. |
#38
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
Floyd L. Davidson spake thus:
David Nebenzahl wrote: Don Pearce spake thus: On Wed, 19 Apr 2006 07:26:25 -0700, "Richard Crowley" wrote: "Laurence Payne" wrote... There'll probably be 3 phases in the street. houses, or groups of houses will be allocated a single phase. 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. 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. Reread my earlier post above. In it I described the situation where a business I once owned needed to have a power converter installed for 3-phase. This was in Berkeley, in a commercial district, not a residential one, and I think it's pretty typical of the Bay Area in general, probably the urban U.S for that matter. The power companies don't supply 3-phase power even to commercial areas; if someone needs it, they put in a converter. (We had a printing press that required it.) Most commercial businesses don't need 3-phase power. Large industrial customers do. I think the converters can be shared, so if a couple or a few neighboring businesses need 3-phase power, they can all use the one converter. What is a "converter"? I've never heard of anything described that way. It's a device--a big, honking piece of electromagnetic equipment--that generates 3-phase power from 2-phase power. In this case, it sits in an underground vault beneath the sidewalk, covered by one of them metal plates. Virtually all power is generated as 3-phase... Nope. What you actually get merely depends on what the transformer arrangement is. Single phase residential power is nothing other than one phase from a 3 phase distribution system. All that is required to have 3 phase power is *more wires*! Apparently not. If you don't believe me, ask PG&E (Pacific Greed and Extortion, as they're known around here). They don't run all 3 wires as part of their normal power distribution. I know this thing exists, because I saw the crews working on the damn thing in front of my shop when it malfunctioned and the press stopped working. -- Pierre, mon ami. Jetez encore un Scientologiste dans le baquet d'acide. - from a posting in alt.religion.scientology titled "France recommends dissolving Scientologists" |
#39
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
On Wed, 19 Apr 2006 13:44:48 -0700, David Nebenzahl
wrote: Virtually all power is generated as 3-phase... Nope. What you actually get merely depends on what the transformer arrangement is. Single phase residential power is nothing other than one phase from a 3 phase distribution system. All that is required to have 3 phase power is *more wires*! Apparently not. If you don't believe me, ask PG&E (Pacific Greed and Extortion, as they're known around here). They don't run all 3 wires as part of their normal power distribution. I know this thing exists, because I saw the crews working on the damn thing in front of my shop when it malfunctioned and the press stopped working. I'm stunned. This is the first time I've ever heard of power being generated as anything other than three phase. Apart from anything else, single phase is mega wasteful of copper. d -- Pearce Consulting http://www.pearce.uk.com |
#40
Posted to alt.engineering.electrical,uk.rec.audio,rec.audio.tech
|
|||
|
|||
10 metres audio cable going into PC = too long?
Eiron spake thus:
And you can't feel 20v AC unless one end is on your tongue. I just tried it. :-) Some of us may be more sensitive than others. It's a subjective thing, after all. Believe me, I felt *something*. Being the paranoid electrician type, I let go of that sucker in a hurry! VOM showed ~20v. (Dunno whether AC or DC; I'm assuming AC.) -- Pierre, mon ami. Jetez encore un Scientologiste dans le baquet d'acide. - from a posting in alt.religion.scientology titled "France recommends dissolving Scientologists" |
Reply |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Topic Police | Pro Audio | |||
DNC Schedule of Events | Pro Audio |