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Houston Wire 2-conductor with shield question...
I went to my local electrical supplier today to try and get a 1000'
spool of 2 conductor+shield wire for headphone cue runs and also for general short run balanced wiring...sometimes 30ft or less microphone runs or balanced line level runs. They said that they did not carry west penn wire, but they carried Houston Wire. They had 2conductor+shield 18 gauge (#HW58730). 2 questions: 1) I was curious if the "shield" surrounded the 2 conductors, but it didnt... it just ran parallel with the other 2 conductors. Is this OK? Why is it called a "shield" if it doesnt shield, but just runs parallel? 2) Is the quoted price of $144.50 too much? A friend of mine told me to expect around $70 for a 1000' spool of westpenn wire. thx, frenchy |
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#2
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Houston Wire 2-conductor with shield question... Group: rec.audio.pro Date: Mon, Nov 22, 2004, 12:57pm From: (they=A0call=A0me=A0frenchy) I went to my local electrical supplier today to try and get a 1000' spool of 2 conductor+shield wire for headphone cue runs and also for general short run balanced wiring...sometimes 30ft or less microphone runs or balanced line level runs. They said that they did not carry west penn wire, but they carried Houston Wire. They had 2conductor+shield 18 gauge (#HW58730). 2 questions: 1) I was curious if the "shield" surrounded the 2 conductors, but it didnt... it just ran parallel with the other 2 conductors. Is this OK? Why is it called a "shield" if it doesnt shield, but just runs parallel? 2) Is the quoted price of $144.50 too much? A friend of mine told me to expect around $70 for a 1000' spool of westpenn wire. thx, frenchy 18ga is kind of heavy for your purposes. What he showed you is 2 conductor with a ground wire and maybe a foil cover over everything. That type of construction is ok for permenent installs but not for cables that are going to be flexed a lot. Look for proper 2 conductor shielded microphone cable. Try www.markertek.com. Eric |
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#3
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Houston Wire 2-conductor with shield question... Group: rec.audio.pro Date: Mon, Nov 22, 2004, 12:57pm From: (they=A0call=A0me=A0frenchy) I went to my local electrical supplier today to try and get a 1000' spool of 2 conductor+shield wire for headphone cue runs and also for general short run balanced wiring...sometimes 30ft or less microphone runs or balanced line level runs. They said that they did not carry west penn wire, but they carried Houston Wire. They had 2conductor+shield 18 gauge (#HW58730). 2 questions: 1) I was curious if the "shield" surrounded the 2 conductors, but it didnt... it just ran parallel with the other 2 conductors. Is this OK? Why is it called a "shield" if it doesnt shield, but just runs parallel? 2) Is the quoted price of $144.50 too much? A friend of mine told me to expect around $70 for a 1000' spool of westpenn wire. thx, frenchy 18ga is kind of heavy for your purposes. What he showed you is 2 conductor with a ground wire and maybe a foil cover over everything. That type of construction is ok for permenent installs but not for cables that are going to be flexed a lot. Look for proper 2 conductor shielded microphone cable. Try www.markertek.com. Eric |
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they call me frenchy wrote:
I went to my local electrical supplier today to try and get a 1000' spool of 2 conductor+shield wire for headphone cue runs and also for general short run balanced wiring...sometimes 30ft or less microphone runs or balanced line level runs. They said that they did not carry west penn wire, but they carried Houston Wire. They had 2conductor+shield 18 gauge (#HW58730). That's probably a little better-made than the West Penn stuff. 2 questions: 1) I was curious if the "shield" surrounded the 2 conductors, but it didnt... it just ran parallel with the other 2 conductors. Is this OK? Why is it called a "shield" if it doesnt shield, but just runs parallel? That thin wire is not the shield, it's a drain wire. There is a foil shield that does surround the other conductors. The drain wire just runs parallel to it. When you strip it, the foil shield comes off with the jacket, which makes termination much easier. But if you look inside the jacket that you stripped off, you will see aluminum foil in there. 2) Is the quoted price of $144.50 too much? A friend of mine told me to expect around $70 for a 1000' spool of westpenn wire. That sounds like a reasonable retail price for a decent cable. If you get cheaper cable, it will cost less. If you buy from a wholesaler, it will cost less too. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#5
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they call me frenchy wrote:
I went to my local electrical supplier today to try and get a 1000' spool of 2 conductor+shield wire for headphone cue runs and also for general short run balanced wiring...sometimes 30ft or less microphone runs or balanced line level runs. They said that they did not carry west penn wire, but they carried Houston Wire. They had 2conductor+shield 18 gauge (#HW58730). That's probably a little better-made than the West Penn stuff. 2 questions: 1) I was curious if the "shield" surrounded the 2 conductors, but it didnt... it just ran parallel with the other 2 conductors. Is this OK? Why is it called a "shield" if it doesnt shield, but just runs parallel? That thin wire is not the shield, it's a drain wire. There is a foil shield that does surround the other conductors. The drain wire just runs parallel to it. When you strip it, the foil shield comes off with the jacket, which makes termination much easier. But if you look inside the jacket that you stripped off, you will see aluminum foil in there. 2) Is the quoted price of $144.50 too much? A friend of mine told me to expect around $70 for a 1000' spool of westpenn wire. That sounds like a reasonable retail price for a decent cable. If you get cheaper cable, it will cost less. If you buy from a wholesaler, it will cost less too. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#7
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On Mon, 22 Nov 2004 13:40:20 -0500, (Eric Toline)
wrote: 18ga is kind of heavy for your purposes. What he showed you is 2 conductor with a ground wire and maybe a foil cover over everything. That type of construction is ok for permenent installs but not for cables that are going to be flexed a lot. Look for proper 2 conductor shielded microphone cable. Try www.markertek.com. Eric 18awg is heavy for permanent installs of 30'-50' headphone cues driving low impedance headphones loudly? I was under the impression that 22awg was too thin and 18awg would be better? Microphones dont care whether they use 22 or 18 at these lengths do they? thx, frenchy |
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#9
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#10
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they call me frenchy wrote:
18awg is heavy for permanent installs of 30'-50' headphone cues driving low impedance headphones loudly? No, but with headphones, you don't need a shield! In fact, you might want to go with 18/4 and double-up the ground. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#11
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they call me frenchy wrote:
18awg is heavy for permanent installs of 30'-50' headphone cues driving low impedance headphones loudly? No, but with headphones, you don't need a shield! In fact, you might want to go with 18/4 and double-up the ground. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#12
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Houston Wire 2-conductor with shield question... Group: rec.audio.pro Date: Mon, Nov 22, 2004, 4:40pm From: (they=A0call=A0me=A0frenchy) On Mon, 22 Nov 2004 13:40:20 -0500, (Eric Toline) wrote: 18ga is kind of heavy for your purposes. What he showed you is 2 conductor with a ground wire and maybe a foil cover over everything. That type of construction is ok for permenent installs but not for cables that are going to be flexed a lot. Look for proper 2 conductor shielded microphone cable. Try www.markertek.com. Eric 18awg is heavy for permanent installs of 30'-50' headphone cues driving low impedance headphones loudly? I was under the impression that 22awg was too thin and 18awg would be better? Microphones dont care whether they use 22 or 18 at these lengths do they? thx, frenchy How loud is loud and what guage cable comes attached to your headphones? Bet it's a lot thinner than 18 ga. Microphones don't really care but depending on what connectors you're using the heavier guage could be a problem. All of my mic cables are 20 or 22 gauge Canare star quad. Eric |
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#13
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Houston Wire 2-conductor with shield question... Group: rec.audio.pro Date: Mon, Nov 22, 2004, 4:40pm From: (they=A0call=A0me=A0frenchy) On Mon, 22 Nov 2004 13:40:20 -0500, (Eric Toline) wrote: 18ga is kind of heavy for your purposes. What he showed you is 2 conductor with a ground wire and maybe a foil cover over everything. That type of construction is ok for permenent installs but not for cables that are going to be flexed a lot. Look for proper 2 conductor shielded microphone cable. Try www.markertek.com. Eric 18awg is heavy for permanent installs of 30'-50' headphone cues driving low impedance headphones loudly? I was under the impression that 22awg was too thin and 18awg would be better? Microphones dont care whether they use 22 or 18 at these lengths do they? thx, frenchy How loud is loud and what guage cable comes attached to your headphones? Bet it's a lot thinner than 18 ga. Microphones don't really care but depending on what connectors you're using the heavier guage could be a problem. All of my mic cables are 20 or 22 gauge Canare star quad. Eric |
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#14
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they call me frenchy wrote:
On 22 Nov 2004 13:54:36 -0500, (Scott Dorsey) wrote: They said that they did not carry west penn wire, but they carried Houston Wire. They had 2conductor+shield 18 gauge (#HW58730). That's probably a little better-made than the West Penn stuff. So youve heard of Houston Wire? Do you know that it is better made than WestPenn or is that speculation? The other local electrical supplier stocks Genesis cable and quoted me $98.08 for a 1000' spool (P/N:1214). I have used the Houston stuff, and it's nothing to write home about, but it's more flexible than the West Penn stuff. Note that the shield will not carry much current; it's a shield and not a current-carrying member. You don't want to use this for headphones where the ground impedance needs to be low. I have never used the Genesis cable. Doing a deja search doesnt turn up anything with regards to these brands, let alone a meaningful quality comparison. I guess I am just skeptical of buying these unknown brands as opposed to standard Belden or WestPenn....but on the other side of the coin, could headphone cues really sound that much different when in the end it is still 18AWG 2-conductor with shield? Should I be asking for spec sheets of some kind? No, you should be asking how flexible it is. Buy the cable that is most flexible. Buy unshielded 18/3 or 18/4. attempting to be an informed installer who supports local electrical suppliers, You might try Graybar if you have a local one. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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they call me frenchy wrote:
On 22 Nov 2004 13:54:36 -0500, (Scott Dorsey) wrote: They said that they did not carry west penn wire, but they carried Houston Wire. They had 2conductor+shield 18 gauge (#HW58730). That's probably a little better-made than the West Penn stuff. So youve heard of Houston Wire? Do you know that it is better made than WestPenn or is that speculation? The other local electrical supplier stocks Genesis cable and quoted me $98.08 for a 1000' spool (P/N:1214). I have used the Houston stuff, and it's nothing to write home about, but it's more flexible than the West Penn stuff. Note that the shield will not carry much current; it's a shield and not a current-carrying member. You don't want to use this for headphones where the ground impedance needs to be low. I have never used the Genesis cable. Doing a deja search doesnt turn up anything with regards to these brands, let alone a meaningful quality comparison. I guess I am just skeptical of buying these unknown brands as opposed to standard Belden or WestPenn....but on the other side of the coin, could headphone cues really sound that much different when in the end it is still 18AWG 2-conductor with shield? Should I be asking for spec sheets of some kind? No, you should be asking how flexible it is. Buy the cable that is most flexible. Buy unshielded 18/3 or 18/4. attempting to be an informed installer who supports local electrical suppliers, You might try Graybar if you have a local one. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#16
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In article writes: Doing a deja search doesnt turn up anything with regards to these brands, let alone a meaningful quality comparison. I guess I am just skeptical of buying these unknown brands as opposed to standard Belden or WestPenn....but on the other side of the coin, could headphone cues really sound that much different when in the end it is still 18AWG 2-conductor with shield? Is this a line level signal (to a headphone amplifier) or the headphone level signal (from a headphone amplifier through 50 feet to the headphones)? Either way, 22 gage should do fine. Headphones aren't like speakers and only need a couple of hundred milliwatts, maybe 50 mA for your average 100 ohm headphones. I can see that you're tempted to use two conductor shielded cable for headphones because it has the right number of conductors if you count the shield, but a shield isn't really intended to carry current, and it's carrying the current of both phones. I doubt that you'd have a disaster if you used it in this application - I have run headphones through a 150 foot mic snake and theyv'e sounded just fine for musicians' cues, but there are some technical reasons to use something else. If this isn't for a portable setup you might consider using Cat5 Ethernet cable. That's as cheap as dirt and it's four pairs of #24 wire. Use a pair for each phone and two pairs for the common and you should be able to melt eardrums. -- I'm really Mike Rivers ) However, until the spam goes away or Hell freezes over, lots of IP addresses are blocked from this system. If you e-mail me and it bounces, use your secret decoder ring and reach me he double-m-eleven-double-zero at yahoo |
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#17
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In article writes: Doing a deja search doesnt turn up anything with regards to these brands, let alone a meaningful quality comparison. I guess I am just skeptical of buying these unknown brands as opposed to standard Belden or WestPenn....but on the other side of the coin, could headphone cues really sound that much different when in the end it is still 18AWG 2-conductor with shield? Is this a line level signal (to a headphone amplifier) or the headphone level signal (from a headphone amplifier through 50 feet to the headphones)? Either way, 22 gage should do fine. Headphones aren't like speakers and only need a couple of hundred milliwatts, maybe 50 mA for your average 100 ohm headphones. I can see that you're tempted to use two conductor shielded cable for headphones because it has the right number of conductors if you count the shield, but a shield isn't really intended to carry current, and it's carrying the current of both phones. I doubt that you'd have a disaster if you used it in this application - I have run headphones through a 150 foot mic snake and theyv'e sounded just fine for musicians' cues, but there are some technical reasons to use something else. If this isn't for a portable setup you might consider using Cat5 Ethernet cable. That's as cheap as dirt and it's four pairs of #24 wire. Use a pair for each phone and two pairs for the common and you should be able to melt eardrums. -- I'm really Mike Rivers ) However, until the spam goes away or Hell freezes over, lots of IP addresses are blocked from this system. If you e-mail me and it bounces, use your secret decoder ring and reach me he double-m-eleven-double-zero at yahoo |
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#18
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#22
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they call me frenchy wrote:
On 22 Nov 2004 17:48:07 -0500, (Scott Dorsey) wrote: they call me frenchy wrote: 18awg is heavy for permanent installs of 30'-50' headphone cues driving low impedance headphones loudly? No, but with headphones, you don't need a shield! In fact, you might want to go with 18/4 and double-up the ground. I was looking at buying a 1000' spool so that I could use it for both headphone applications and mic applications. If I get specialty cable for the headphones then my cost effective approach completely changes. I definitely dont wanna get the wrong cable for a given application though, which is why I am doing my homework upfront. Well, you do know this is installed system cable, right? You can't use foil shields for anything but permanent installations. You don't want to be using the same cable for headphone and microphone. They are very different applications. You will be surprised to see how quickly a thousand feet of cable gets used up, too. Don't be afraid of buying different kinds of cable to keep around. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#23
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they call me frenchy wrote:
On 22 Nov 2004 17:48:07 -0500, (Scott Dorsey) wrote: they call me frenchy wrote: 18awg is heavy for permanent installs of 30'-50' headphone cues driving low impedance headphones loudly? No, but with headphones, you don't need a shield! In fact, you might want to go with 18/4 and double-up the ground. I was looking at buying a 1000' spool so that I could use it for both headphone applications and mic applications. If I get specialty cable for the headphones then my cost effective approach completely changes. I definitely dont wanna get the wrong cable for a given application though, which is why I am doing my homework upfront. Well, you do know this is installed system cable, right? You can't use foil shields for anything but permanent installations. You don't want to be using the same cable for headphone and microphone. They are very different applications. You will be surprised to see how quickly a thousand feet of cable gets used up, too. Don't be afraid of buying different kinds of cable to keep around. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#26
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they call me frenchy wrote:
I am noticing that there is something funny going on with what these cables are called vs what is really inside them. Above you call them "two conductor shielded", but inside of them is 2conductors, the foil shield AND a drain wire which does have the ability to carry current. Not much. You will notice that the drain wire is smaller than the other conductors. With headphones, you want the lowest possible ground resistance because the two channels share a common ground. Ground resistance results in the mono signal being reduced and more of the difference signal being heard in the phones, so getting the ground resistance down is MORE important than getting the signal line resistances down. For microphones, the drain wire is connected to pin1. Not sure how the shield foil gets grounded, because you certainly dont solder the shield foil on either end, so the uninsulated drain wire must just make electrical contact with the foil shield during some parts of the cable run. In this application no current flows in the shield foil nor the drain wire except for ground loops, right? Right, or phantom power. The shield foil is bonded to the drain wire. For headphones, the foil shield is not necessary, nor can it carry current, which was your above point, BUT the drain wire absolutely is necessary and CAN carry current back from the headphone drivers. But as scott pointed out, it must carry the current for both the L and R drivers, but it is only as thick as the others...which is a limitation....thus your cat5 idea below. It should be MORE thick than the others. If this isn't for a portable setup you might consider using Cat5 Ethernet cable. That's as cheap as dirt and it's four pairs of #24 wire. Use a pair for each phone and two pairs for the common and you should be able to melt eardrums. Now that is an excellent idea because I will be buying a spool of it anyway. Lets take a look at this further. You say 4 pairs of 24awg wire.... This is the same as 2 pairs of 21 awg wire. You will get substantial losses into 12 ohm phones, but hardly any loss into 600 ohm phones. I knew I came here for a reason. I was trying to be a thrifty shopper and use a 1000' spool for 2 different reasons. Looks like I will be using Cat5 cable for 2 different reasons....and just get the best microhpone cable for mic sends and balanced line level sends. But, cat 5 cable costs more than the correct cable. Thx for your help. Last thought...can I use cat5 for gigabit ethernet...or is it limited to 100Mbps ethernet? You really want cat5e or higher. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#27
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they call me frenchy wrote:
I am noticing that there is something funny going on with what these cables are called vs what is really inside them. Above you call them "two conductor shielded", but inside of them is 2conductors, the foil shield AND a drain wire which does have the ability to carry current. Not much. You will notice that the drain wire is smaller than the other conductors. With headphones, you want the lowest possible ground resistance because the two channels share a common ground. Ground resistance results in the mono signal being reduced and more of the difference signal being heard in the phones, so getting the ground resistance down is MORE important than getting the signal line resistances down. For microphones, the drain wire is connected to pin1. Not sure how the shield foil gets grounded, because you certainly dont solder the shield foil on either end, so the uninsulated drain wire must just make electrical contact with the foil shield during some parts of the cable run. In this application no current flows in the shield foil nor the drain wire except for ground loops, right? Right, or phantom power. The shield foil is bonded to the drain wire. For headphones, the foil shield is not necessary, nor can it carry current, which was your above point, BUT the drain wire absolutely is necessary and CAN carry current back from the headphone drivers. But as scott pointed out, it must carry the current for both the L and R drivers, but it is only as thick as the others...which is a limitation....thus your cat5 idea below. It should be MORE thick than the others. If this isn't for a portable setup you might consider using Cat5 Ethernet cable. That's as cheap as dirt and it's four pairs of #24 wire. Use a pair for each phone and two pairs for the common and you should be able to melt eardrums. Now that is an excellent idea because I will be buying a spool of it anyway. Lets take a look at this further. You say 4 pairs of 24awg wire.... This is the same as 2 pairs of 21 awg wire. You will get substantial losses into 12 ohm phones, but hardly any loss into 600 ohm phones. I knew I came here for a reason. I was trying to be a thrifty shopper and use a 1000' spool for 2 different reasons. Looks like I will be using Cat5 cable for 2 different reasons....and just get the best microhpone cable for mic sends and balanced line level sends. But, cat 5 cable costs more than the correct cable. Thx for your help. Last thought...can I use cat5 for gigabit ethernet...or is it limited to 100Mbps ethernet? You really want cat5e or higher. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#28
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In article writes: I am noticing that there is something funny going on with what these cables are called vs what is really inside them. Above you call them "two conductor shielded", but inside of them is 2conductors, the foil shield AND a drain wire which does have the ability to carry current. That's what we call two-conductor shielded cable. Sure, the shield and drain wire can carry current but they aren't supposed to. The shield is supposed to be just that - a shield. The reason for the drain wire is so that you can connect the shield to the box (through the connector) so you have a continuous shield - one box, another box, and the shield of the wire connecting them. That's what keeps goblins out. For microphones, the drain wire is connected to pin1. Not sure how the shield foil gets grounded, because you certainly dont solder the shield foil on either end The shield is in physical contact with the drain wire so they're also electrically connected. The reason for the drain wire is because you can't solder to the foil shield. Wire with a braided shield may or may not have a drain wire. If it doesn't, you just unbraid the shield a bit at the end and solder to that. Or you use crimp connections on the shield. In this application no current flows in the shield foil nor the drain wire except for ground loops, right? That's correct (and of course you shouldn't have a ground loop). This is why the shield or drain isn't designed to any particular current carrying specification. For headphones, the foil shield is not necessary, nor can it carry current, which was your above point, BUT the drain wire absolutely is necessary and CAN carry current back from the headphone drivers. Well it doesn't matter which you consider to be the current carrier, and in fact the shield and drain are electrically in parallel, so they both carry some current. Now that is an excellent idea because I will be buying a spool of it anyway. Lets take a look at this further. You say 4 pairs of 24awg wire.... Pair1a Headphone1 L+ Pair1b Headphone1 R+ Pair2a Headphone2 L+ Pair2b Headphone2 R+ Pair3a Headphone1 COM Pair3b Headphone1 COM Pair4a Headphone2 COM Pair4b Headphone2 COM Well, I was thinking more along the lines of Pair 1A - Headphone L Pair 1B - Headphone Common Pair 2A - Headphone R Pair 2B - Headphone Common etc. That way, you'll maintain pairs and if you're going to run two sets of headphones through the cable, you might get a little less crosstalk by using a pair per headphone (headphone and common) rather than using a pair for right and left, and another pair doubled up for the common. Twisted pairs tend to work that way, but it might not be significant. I knew I came here for a reason. I was trying to be a thrifty shopper and use a 1000' spool for 2 different reasons. Looks like I will be using Cat5 cable for 2 different reasons....and just get the best microhpone cable for mic sends and balanced line level sends. According to Steve Lampen of Belden, their Cat5e or Cat6 cable makes great balanced line level cable if you can live without the shield (which you should be able to do at line levels if your inputs and outputs are balanced). In fact, Steve's talking to a manufacturer about making adapters with a DB25 on one side and two RJ45s on the other, for connecting DB25-based 8-channel devices using two pieces of Ethernet cable with standard RJ45 connectors. Thx for your help. Last thought...can I use cat5 for gigabit ethernet...or is it limited to 100Mbps ethernet? I'm not a networ person, but I know that as the speed goes up, so do the numbers. I'd use Cat6 for gigabit, but I imagine someone with network smarts knows for sure. -- I'm really Mike Rivers ) However, until the spam goes away or Hell freezes over, lots of IP addresses are blocked from this system. If you e-mail me and it bounces, use your secret decoder ring and reach me he double-m-eleven-double-zero at yahoo |
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#29
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In article writes: I am noticing that there is something funny going on with what these cables are called vs what is really inside them. Above you call them "two conductor shielded", but inside of them is 2conductors, the foil shield AND a drain wire which does have the ability to carry current. That's what we call two-conductor shielded cable. Sure, the shield and drain wire can carry current but they aren't supposed to. The shield is supposed to be just that - a shield. The reason for the drain wire is so that you can connect the shield to the box (through the connector) so you have a continuous shield - one box, another box, and the shield of the wire connecting them. That's what keeps goblins out. For microphones, the drain wire is connected to pin1. Not sure how the shield foil gets grounded, because you certainly dont solder the shield foil on either end The shield is in physical contact with the drain wire so they're also electrically connected. The reason for the drain wire is because you can't solder to the foil shield. Wire with a braided shield may or may not have a drain wire. If it doesn't, you just unbraid the shield a bit at the end and solder to that. Or you use crimp connections on the shield. In this application no current flows in the shield foil nor the drain wire except for ground loops, right? That's correct (and of course you shouldn't have a ground loop). This is why the shield or drain isn't designed to any particular current carrying specification. For headphones, the foil shield is not necessary, nor can it carry current, which was your above point, BUT the drain wire absolutely is necessary and CAN carry current back from the headphone drivers. Well it doesn't matter which you consider to be the current carrier, and in fact the shield and drain are electrically in parallel, so they both carry some current. Now that is an excellent idea because I will be buying a spool of it anyway. Lets take a look at this further. You say 4 pairs of 24awg wire.... Pair1a Headphone1 L+ Pair1b Headphone1 R+ Pair2a Headphone2 L+ Pair2b Headphone2 R+ Pair3a Headphone1 COM Pair3b Headphone1 COM Pair4a Headphone2 COM Pair4b Headphone2 COM Well, I was thinking more along the lines of Pair 1A - Headphone L Pair 1B - Headphone Common Pair 2A - Headphone R Pair 2B - Headphone Common etc. That way, you'll maintain pairs and if you're going to run two sets of headphones through the cable, you might get a little less crosstalk by using a pair per headphone (headphone and common) rather than using a pair for right and left, and another pair doubled up for the common. Twisted pairs tend to work that way, but it might not be significant. I knew I came here for a reason. I was trying to be a thrifty shopper and use a 1000' spool for 2 different reasons. Looks like I will be using Cat5 cable for 2 different reasons....and just get the best microhpone cable for mic sends and balanced line level sends. According to Steve Lampen of Belden, their Cat5e or Cat6 cable makes great balanced line level cable if you can live without the shield (which you should be able to do at line levels if your inputs and outputs are balanced). In fact, Steve's talking to a manufacturer about making adapters with a DB25 on one side and two RJ45s on the other, for connecting DB25-based 8-channel devices using two pieces of Ethernet cable with standard RJ45 connectors. Thx for your help. Last thought...can I use cat5 for gigabit ethernet...or is it limited to 100Mbps ethernet? I'm not a networ person, but I know that as the speed goes up, so do the numbers. I'd use Cat6 for gigabit, but I imagine someone with network smarts knows for sure. -- I'm really Mike Rivers ) However, until the spam goes away or Hell freezes over, lots of IP addresses are blocked from this system. If you e-mail me and it bounces, use your secret decoder ring and reach me he double-m-eleven-double-zero at yahoo |
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#31
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For microphones, the drain wire is connected to pin1. Not sure how the shield foil gets grounded, because you certainly dont solder the shield foil on either end The shield is in physical contact with the drain wire so they're also electrically connected. The reason for the drain wire is because you can't solder to the foil shield. Wire with a braided shield may or may not have a drain wire. If it doesn't, you just unbraid the shield a bit at the end and solder to that. Or you use crimp connections on the shield. In this application no current flows in the shield foil nor the drain wire except for ground loops, right? That's correct (and of course you shouldn't have a ground loop). This is why the shield or drain isn't designed to any particular current carrying specification. Can I play devil's advocate regarding the ground loop when connecting two different pieces of line level gear using balanced mic cable... I am testing my understanding, lemme know if my logic is flawed... By definition you create a ground loop because the gear on each side is each connected to ground through the AC safety ground which should never be lifted....then the gear is connectected together by the drain wire that we have been speaking about (pin1)...so by definition we have created an intentional ground loop....intentionally violating the rule that I have heard Scott Dorsey say before that each peice of gear should have one and only one path to ground. ....So now that we have intentionally created this ground loop...the problem will or will not be noticed depending on whether current flows in this ground loop. If the gear is each on the same AC circuit, then there is no reason for current to flow because the grounds are at the same potential. If the gear is on separate circuits (which they very well could be in a medium sized studio with different rooms and lots of gear), then the two different circuits must each go directly to the same electrical distribution box and share the same Low impedance path to earth from there...in which case no ground current flows and no problem exists...even though we have intentionally soldered a ground loop together. An audible problem exists when the two different circuits do not share the same low impedance path to earth. This discussion doesnt even account for the fact that some gear throws nasty stuff onto the ground lines and causes audible noise even if the wiring is proper. Is this correct? I am re-wiring my studio all the time and as I learn more, I do it different each time. I keep adding more gear and more rooms, so I cant run everything on the same circuit anymore like I used to. thank you very much, frenchy |
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#32
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they call me frenchy wrote:
By definition you create a ground loop because the gear on each side is each connected to ground through the AC safety ground which should never be lifted....then the gear is connectected together by the drain wire that we have been speaking about (pin1)...so by definition we have created an intentional ground loop....intentionally violating the rule that I have heard Scott Dorsey say before that each peice of gear should have one and only one path to ground. Right. Now note that this doesn't happen for things like microphones (which aren't plugged into the wall) or things with two-prong plugs and no other connections (say, cassette decks). ...So now that we have intentionally created this ground loop...the problem will or will not be noticed depending on whether current flows in this ground loop. If the gear is each on the same AC circuit, then there is no reason for current to flow because the grounds are at the same potential. If the gear is on separate circuits (which they very well could be in a medium sized studio with different rooms and lots of gear), then the two different circuits must each go directly to the same electrical distribution box and share the same Low impedance path to earth from there...in which case no ground current flows and no problem exists...even though we have intentionally soldered a ground loop together. An audible problem exists when the two different circuits do not share the same low impedance path to earth. This discussion doesnt even account for the fact that some gear throws nasty stuff onto the ground lines and causes audible noise even if the wiring is proper. Right. The larger the physical size of the loop, the worse of a noise pickup problem you're going to have in general. Throwing nasty stuff on the power line is fine, IF the nasty stuff is the same at all outlets and therefore gets cancelled out. But this never happens since it's mostly so high frequency that the cable reactance makes a big difference in level. Is this correct? I am re-wiring my studio all the time and as I learn more, I do it different each time. I keep adding more gear and more rooms, so I cant run everything on the same circuit anymore like I used to. If you run everything balanced, this doesn't matter, because you CAN break the audio grounds with impunity. A box full of XLR ground lift adaptors is a fine thing to have around. The thing is that you need it sit down and figure out which ones to break. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#33
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In article writes: Can I play devil's advocate regarding the ground loop when connecting two different pieces of line level gear using balanced mic cable... I am testing my understanding, lemme know if my logic is flawed... Oh, you can always screw up a good thing, but if the two pieces are properly designed, there won't be a ground loop. By definition you create a ground loop because the gear on each side is each connected to ground through the AC safety ground which should never be lifted....then the gear is connectected together by the drain wire that we have been speaking about (pin1)...so by definition we have created an intentional ground loop....intentionally violating the rule that I have heard Scott Dorsey say before that each peice of gear should have one and only one path to ground. This is where the "properly designed" comes in. The safety ground and the shield should be tied together at a single point inside the box. If the shield is connected to pin 1, which goes through a meandering circuit board trace, eventually finding its way to the ground (reference) point on the power supply, and if the safety ground wire is just attached to a convenient screw inside the chassis, then you have what's known as "The Pin 1 Problem." This can be fixed. You get to make the assumption that two power cords plugged into adjacent outlets have the safety ground at the same potential. And if the shield is connected to the same point, it's at the same potential, hence no ground loop current. It's not perfect, but it's a lot closer than random or haphazard ground connections in equipment as was prevalent in the early "semi pro" days. -- I'm really Mike Rivers ) However, until the spam goes away or Hell freezes over, lots of IP addresses are blocked from this system. If you e-mail me and it bounces, use your secret decoder ring and reach me he double-m-eleven-double-zero at yahoo |
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#34
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#35
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: So, since Cat5 cable is 24awg, is this wire big
enough for a : send/return for a headphone channel? Per your above, you would have : 24AWG sending Headphone #1 L and 24AWG returning Headphone #1 L. This rather delux headphone system hooks with cat5 http://www.musiciansfriend.com/srs7/...se_pid/241501/ Phil Abbate : |
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#36
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In article writes: So, since Cat5 cable is 24awg, is this wire big enough for a send/return for a headphone channel? It depends on how long the cable run is, the impedance of your headphones, and how much power you can pump into the headphones before they blow up. #24 wire is about 2.5 ohms per 100 feet, so for a 100 foot run, you'd be putting 5 ohms in series with them. That would be significant if you were driving 8 ohm loudspeakers at 50 watts, but for headphones with 50 to 150 ohms impedance at 150 milliwatts, I'd say you can live with it. I am about to order Parts Express#100-415 cable it is $44 for a 1000' box....but it is solid wire. I dont think this will matter for permanent installs right? Nope. -- I'm really Mike Rivers ) However, until the spam goes away or Hell freezes over, lots of IP addresses are blocked from this system. If you e-mail me and it bounces, use your secret decoder ring and reach me he double-m-eleven-double-zero at yahoo |
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#37
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So, since Cat5 cable is 24awg, is this wire big
enough for a : send/return for a headphone channel? Per your above, you would have : 24AWG sending Headphone #1 L and 24AWG returning Headphone #1 L. This rather delux headphone system hooks with cat5 snip link to Furman HDS6 system The Furman HDS6 does not send amplified headphone levels down the Cat5 cables. The master unit sends line level audio & DC voltage to the remote submixer units which amplify the signal. Scott Fraser |
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#38
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Mike Rivers wrote: In article writes: Big snip According to Steve Lampen of Belden, their Cat5e or Cat6 cable makes great balanced line level cable if you can live without the shield (which you should be able to do at line levels if your inputs and outputs are balanced). In fact, Steve's talking to a manufacturer about making adapters with a DB25 on one side and two RJ45s on the other, for connecting DB25-based 8-channel devices using two pieces of Ethernet cable with standard RJ45 connectors. Aye but you can get sheilded CAT5. At work we started using CAT5 for AES/EBU and analog audio in 1996. We ran tests with 1000' spools and then wrote a white paper regarding this application. Good to see it's been adopted in general. |
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#39
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#40
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In article znr1102605079k@trad, Mike Rivers wrote:
In article . com writes: Aye but you can get sheilded CAT5. I've seen it with an overall shield (not sure what this is called) but not with individually shielded pairs. Does overally shielding make any difference in the performance of the cable for audio? It will in the case of electrostatically-induced noise sources. Always a help, especially if the lines aren't perfectly balanced. You can even get the patch cable with overall shield. I recommend going the patch cable route. Stranding is good. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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