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#1
Posted to rec.audio.tech
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need help choosing between line level cables
I'm looking to buy cabling to run line-level stereo audio through the
walls of my home (tape mon output of one receiver/amp, thru walls and into another amp). It's for an outdoor stereo so I don't need the end-all-be-all best sound, just decent, humless audio. The most common cabling choice seems to be Belden 9451D. Another Belden cable, 8723, looks identical--I can't see what the difference is. Does anyone have an opinion on which is better? I'd prefer the 8723 since I can find it sold by the foot, the 9451D is only available in bulk. Belden 8723: http://www.weisd.com/store2/BEL8723%20060U1000B.html Belden 9451D: http://www.sjmediasystem.com/bl-9451d-1000.html |
#2
Posted to rec.audio.tech
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need help choosing between line level cables
"toecheese" wrote ...
I'm looking to buy cabling to run line-level stereo audio through the walls of my home (tape mon output of one receiver/amp, thru walls and into another amp). It's for an outdoor stereo so I don't need the end-all-be-all best sound, just decent, humless audio. The most common cabling choice seems to be Belden 9451D. Another Belden cable, 8723, looks identical--I can't see what the difference is. Does anyone have an opinion on which is better? I'd prefer the 8723 since I can find it sold by the foot, the 9451D is only available in bulk. Belden 8723: http://www.weisd.com/store2/BEL8723%20060U1000B.html Belden 9451D: http://www.sjmediasystem.com/bl-9451d-1000.html I would buy whatever is cheaper and/or more convenient. It is unlikely you will experience any performance difference between those two cable models. There are likely even less expensive options for install-grade shielded twisted-pair audio cable. I'm a big fan of good-old Belden cable, but for fixed-install use at home, I'd rather save some $$ on the cable and spend it on good balancing transformers for each end. Of course you ARE using balancing transformers at each end, right? Without transformers, at least at ONE end, you will likely run into ground-loop hum problems that cannot be fixed with even the most expensive cable. |
#3
Posted to rec.audio.tech
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need help choosing between line level cables
Of course you ARE using balancing transformers at each end, right? Without transformers, at least at ONE end, you will likely run into ground-loop hum problems that cannot be fixed with even the most expensive cable. I wasn't planning on it, no. I'm not using grounded equipment, so I figured ground loops wouldn't be an issue. |
#4
Posted to rec.audio.tech
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need help choosing between line level cables
"toecheese" wrote ...
Of course you ARE using balancing transformers at each end, right? Without transformers, at least at ONE end, you will likely run into ground-loop hum problems that cannot be fixed with even the most expensive cable. I wasn't planning on it, no. I'm not using grounded equipment, so I figured ground loops wouldn't be an issue. It has little to do with whether your equipment is gounded or not. You might get lucky, but don't plan on it. Annother option that is becoming more popular these days is using computer networking cable ("Cat5" UTP Unshielded Twisted Pair). There are many sources of balun transformers for both audio and video to use this inexpensive (but super-balanced) cable. That would be my first choice for new installations. For example... http://www.mcmelectronics.com/product/50-7725 |
#5
Posted to rec.audio.tech
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need help choosing between line level cables
Good to know, I'll see first if I get a hum and if so I'll try the
transformer. using CAT5 sounds interesting, but does that give me a stereo pair or would I need two separate CAT5 cables? As it is the Belden stereo cable is only about $25 for the 60 foot run I need. |
#6
Posted to rec.audio.tech
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need help choosing between line level cables
"toecheese" wrote...
Good to know, I'll see first if I get a hum and if so I'll try the transformer. using CAT5 sounds interesting, but does that give me a stereo pair or would I need two separate CAT5 cables? As it is the Belden stereo cable is only about $25 for the 60 foot run I need. You actually get four pair in a Cat5 cable. The advantage of Cat5 is that you can run video (and even computer network !) over it. The audio cable is pretty much a one- trick pony. 75 ft of Cat5 is $11 at my local shop. Complete with connectors already installed. |
#7
Posted to rec.audio.tech
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need help choosing between line level cables
Richard Crowley wrote: "toecheese" wrote ... I'm looking to buy cabling to run line-level stereo audio through the walls of my home (tape mon output of one receiver/amp, thru walls and into another amp). It's for an outdoor stereo so I don't need the end-all-be-all best sound, just decent, humless audio. The most common cabling choice seems to be Belden 9451D. Another Belden cable, 8723, looks identical--I can't see what the difference is. Does anyone have an opinion on which is better? I'd prefer the 8723 since I can find it sold by the foot, the 9451D is only available in bulk. Belden 8723: http://www.weisd.com/store2/BEL8723%20060U1000B.html Belden 9451D: http://www.sjmediasystem.com/bl-9451d-1000.html I would buy whatever is cheaper and/or more convenient. It is unlikely you will experience any performance difference between those two cable models. There are likely even less expensive options for install-grade shielded twisted-pair audio cable. I'm a big fan of good-old Belden cable, but for fixed-install use at home, I'd rather save some $$ on the cable and spend it on good balancing transformers for each end. Of course you ARE using balancing transformers at each end, right? Without transformers, at least at ONE end, you will likely run into ground-loop hum problems that cannot be fixed with even the most expensive cable. Nonsense. You only need a transformer at ONE end. How the heck do you think you'll get an earth loop ? Graham |
#8
Posted to rec.audio.tech
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need help choosing between line level cables
Richard Crowley wrote: "toecheese" wrote ... Of course you ARE using balancing transformers at each end, right? Without transformers, at least at ONE end, you will likely run into ground-loop hum problems that cannot be fixed with even the most expensive cable. I wasn't planning on it, no. I'm not using grounded equipment, so I figured ground loops wouldn't be an issue. It has little to do with whether your equipment is gounded or not. Yes it DOES. Graham |
#9
Posted to rec.audio.tech
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need help choosing between line level cables
I'm looking to buy cabling to run line-level stereo audio through the
walls of my home (tape mon output of one receiver/amp, thru walls and into another amp). It's for an outdoor stereo so I don't need the end-all-be-all best sound, just decent, humless audio. The most common cabling choice seems to be Belden 9451D. Another Belden cable, 8723, looks identical--I can't see what the difference is. The 9451D insulates the wires with polyolefin, wraps each pair of wires in a foil shield with a drain wire, and then jackets each shielded pair with PVC. The two shielded-and-insulated pairs are placed side by side, in a zipcord-style arrangement. The 8723 insulates the wires with polypropylene, wraps each pair of insulated wires in a foil shield, places _both_ shielded wires and a single drain wire in a single PVC outer jacket. The 9451D might be a bit easier to terminate if you're planning to terminate to individual RCA plugs/jackets, thanks to its zipcord-style arrangement. The 8723 has a narrow diameter, and it might be easier to terminate in some sort of single stereo connector. I don't know whether one is more flexible than the other, which might make a difference when installing. Does anyone have an opinion on which is better? I'd prefer the 8723 since I can find it sold by the foot, the 9451D is only available in bulk. In the sort of application you are considering, I don't think that either has an electrical or sonic advantage over the other. Make the choice for reasons of cost, availability, or convenience. -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#10
Posted to rec.audio.tech
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need help choosing between line level cables
toecheese wrote: Good to know, I'll see first if I get a hum and if so I'll try the transformer. using CAT5 sounds interesting, but does that give me a stereo pair or would I need two separate CAT5 cables? As it is the Belden stereo cable is only about $25 for the 60 foot run I need. Cat 5 gives you FOUR twisted pairs but they're unscreened (it's UTP = unscreened twisted pair) hence you would likely need a balancing transformer at the far end. http://en.wikipedia.org/wiki/Category_5_cable There's nothing special about Belden cable for your purposes btw. Graham |
#11
Posted to rec.audio.tech
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need help choosing between line level cables
Richard Crowley wrote: "toecheese" wrote... Good to know, I'll see first if I get a hum and if so I'll try the transformer. using CAT5 sounds interesting, but does that give me a stereo pair or would I need two separate CAT5 cables? As it is the Belden stereo cable is only about $25 for the 60 foot run I need. You actually get four pair in a Cat5 cable. The advantage of Cat5 is that you can run video (and even computer network !) over it. The audio cable is pretty much a one- trick pony. 75 ft of Cat5 is $11 at my local shop. Complete with connectors already installed. And a couple of good audio transformers is probably ~ $200 ! Graham |
#12
Posted to rec.audio.tech
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need help choosing between line level cables
using CAT5 sounds interesting, but does that give me a stereo pair or
would I need two separate CAT5 cables? CAT5 has four twisted pairs - you could carry two stereo pairs in a single run. -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#13
Posted to rec.audio.tech
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need help choosing between line level cables
"Eeyore" wrote...
Richard Crowley wrote: "toecheese" wrote... Good to know, I'll see first if I get a hum and if so I'll try the transformer. using CAT5 sounds interesting, but does that give me a stereo pair or would I need two separate CAT5 cables? As it is the Belden stereo cable is only about $25 for the 60 foot run I need. You actually get four pair in a Cat5 cable. The advantage of Cat5 is that you can run video (and even computer network !) over it. The audio cable is pretty much a one- trick pony. 75 ft of Cat5 is $11 at my local shop. Complete with connectors already installed. And a couple of good audio transformers is probably ~ $200 ! And I'd bet that he will need transformers (of whatever grade) regardless of what kind of cable he uses. Running 65 feet of cable between pieces of consumer audio equipment in different rooms is a standard setup for hum and similar problems. Perhaps you missed my reference to a $35 solution. |
#14
Posted to rec.audio.tech
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need help choosing between line level cables
Richard Crowley wrote: "Eeyore" wrote... Richard Crowley wrote: "toecheese" wrote... Good to know, I'll see first if I get a hum and if so I'll try the transformer. using CAT5 sounds interesting, but does that give me a stereo pair or would I need two separate CAT5 cables? As it is the Belden stereo cable is only about $25 for the 60 foot run I need. You actually get four pair in a Cat5 cable. The advantage of Cat5 is that you can run video (and even computer network !) over it. The audio cable is pretty much a one- trick pony. 75 ft of Cat5 is $11 at my local shop. Complete with connectors already installed. And a couple of good audio transformers is probably ~ $200 ! And I'd bet that he will need transformers (of whatever grade) regardless of what kind of cable he uses. Running 65 feet of cable between pieces of consumer audio equipment in different rooms is a standard setup for hum and similar problems. Not at all when there's no common mains ground connection. Graham |
#15
Posted to rec.audio.tech
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need help choosing between line level cables
"Eeyore" wrote ...
Richard Crowley wrote: And I'd bet that he will need transformers (of whatever grade) regardless of what kind of cable he uses. Running 65 feet of cable between pieces of consumer audio equipment in different rooms is a standard setup for hum and similar problems. Not at all when there's no common mains ground connection. Your optimism is admirable and I would be very grateful if it were accurate. Alas, it doesn't wash in my reality. (Not to mention the numerous posts from people who have tried it and come here asking for solutions.) I'm willing to wait for the results of the OP's actual implementation. |
#16
Posted to rec.audio.tech
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need help choosing between line level cables
Richard Crowley wrote: "Eeyore" wrote ... Richard Crowley wrote: And I'd bet that he will need transformers (of whatever grade) regardless of what kind of cable he uses. Running 65 feet of cable between pieces of consumer audio equipment in different rooms is a standard setup for hum and similar problems. Not at all when there's no common mains ground connection. Your optimism is admirable and I would be very grateful if it were accurate. I've had no trouble with that style of working myself. Alas, it doesn't wash in my reality. (Not to mention the numerous posts from people who have tried it and come here asking for solutions.) I'm willing to wait for the results of the OP's actual implementation. In order for there to be a ground loop there first has to be a LOOP ! The issue with laptops is something else entirely. Graham |
#17
Posted to rec.audio.tech
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need help choosing between line level cables
In article WY6dndLx74TP4J_VnZ2dnUVZ_t6onZ2d@pcez,
"Richard Crowley" wrote: "Eeyore" wrote... Richard Crowley wrote: "toecheese" wrote... Good to know, I'll see first if I get a hum and if so I'll try the transformer. using CAT5 sounds interesting, but does that give me a stereo pair or would I need two separate CAT5 cables? As it is the Belden stereo cable is only about $25 for the 60 foot run I need. You actually get four pair in a Cat5 cable. The advantage of Cat5 is that you can run video (and even computer network !) over it. The audio cable is pretty much a one- trick pony. 75 ft of Cat5 is $11 at my local shop. Complete with connectors already installed. And a couple of good audio transformers is probably ~ $200 ! And I'd bet that he will need transformers (of whatever grade) regardless of what kind of cable he uses. Running 65 feet of cable between pieces of consumer audio equipment in different rooms is a standard setup for hum and similar problems. Perhaps you missed my reference to a $35 solution. $15 for Cat6 and $20 left over for balancing transformers? I don't think that would work well. He gave links to balanced wiring. Balanced audio allows for a bit of a grounding mismatch between equipment. If his equipment supports it, balanced wiring is by far the cheapest and highest quality way to do this. -- Block Google's spam and enjoy Usenet again. Reply with Google and I won't hear from you. |
#18
Posted to rec.audio.tech
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need help choosing between line level cables
Kevin McMurtrie wrote: "Richard Crowley" wrote: "Eeyore" wrote... Richard Crowley wrote: "toecheese" wrote... Good to know, I'll see first if I get a hum and if so I'll try the transformer. using CAT5 sounds interesting, but does that give me a stereo pair or would I need two separate CAT5 cables? As it is the Belden stereo cable is only about $25 for the 60 foot run I need. You actually get four pair in a Cat5 cable. The advantage of Cat5 is that you can run video (and even computer network !) over it. The audio cable is pretty much a one- trick pony. 75 ft of Cat5 is $11 at my local shop. Complete with connectors already installed. And a couple of good audio transformers is probably ~ $200 ! And I'd bet that he will need transformers (of whatever grade) regardless of what kind of cable he uses. Running 65 feet of cable between pieces of consumer audio equipment in different rooms is a standard setup for hum and similar problems. Perhaps you missed my reference to a $35 solution. $15 for Cat6 and $20 left over for balancing transformers? I don't think that would work well. He gave links to balanced wiring. Balanced audio allows for a bit of a grounding mismatch between equipment. Errr ... that's not actually quite the intention per se but it would cope with that. If his equipment supports it, balanced wiring is by far the cheapest and highest quality way to do this. Balanced wiring only gives you an advantage if the equipment is balanced. With clever wiring it's only actually necessary for either the 'sending' or 'receiving' equipment to have a balanced input or ouput but you need to know what you're doing in this case. Graham |
#19
Posted to rec.audio.tech
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need help choosing between line level cables
"Eeyore" wrote in
message Balanced wiring only gives you an advantage if the equipment is balanced. With clever wiring it's only actually necessary for either the 'sending' or 'receiving' equipment to have a balanced input or ouput but you need to know what you're doing in this case. I know the strong advantage that balanced inputs give, but what advantage do you get from an electronically-balanced output driving an unbalanced input? |
#20
Posted to rec.audio.tech
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need help choosing between line level cables
On Tue, 15 Apr 2008 07:52:51 -0400, "Arny Krueger"
wrote: "Eeyore" wrote in message Balanced wiring only gives you an advantage if the equipment is balanced. With clever wiring it's only actually necessary for either the 'sending' or 'receiving' equipment to have a balanced input or ouput but you need to know what you're doing in this case. I know the strong advantage that balanced inputs give, but what advantage do you get from an electronically-balanced output driving an unbalanced input? Provided you have an appropriate balun, like a transformer at the input, you get all of the advantages. d -- d |
#21
Posted to rec.audio.tech
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need help choosing between line level cables
"Don Pearce" wrote in message
... On Tue, 15 Apr 2008 07:52:51 -0400, "Arny Krueger" wrote: "Eeyore" wrote in message Balanced wiring only gives you an advantage if the equipment is balanced. With clever wiring it's only actually necessary for either the 'sending' or 'receiving' equipment to have a balanced input or ouput but you need to know what you're doing in this case. I know the strong advantage that balanced inputs give, but what advantage do you get from an electronically-balanced output driving an unbalanced input? Provided you have an appropriate balun, like a transformer at the input, you get all of the advantages. d -- d Yes but then you're driving a balanced input aren't you ;-) If you have an electronically balanced output (hence usually but not always referred to ground) driving an unbalanced input, I can't see what real benefit you will get however clever you are with wiring. What you use a balanced system for is to get rid of common-mode noise, usually in the form of hum, but also higher frequencies. Unbalancing at the receiving end will remove the common-mode rejection. If I were doing what the OP is doing, I would wire my house with CAT5/6 cable which is really cheap these days, then use equipment with balanced I/O. As already mentioned, CAT5/6 can carry 4 balanced audio signals, so you either get 2 stereos or a send and return stereo pair in each cable. Crosstalk isn't an issue with balanced operation. If suitable balanced equipment isn't available, then there are some alternatives. Transformers are definitely one, and they have the advantage of fully-floating operation and galvanic insulation. However, good transformers are expensive, although it's not necessary these days to have transformers which will drive 600 ohm lines, 10k-10k transformers are somewhat cheaper. Other alternatives are to get some pro units like the Henry Matchbox which lists at $225 for a bi-directional interface, therefore equivalent to 4 transformers. I would guess that the street price for the Matchbox is under $200 and as these things don't wear out, it may be possible to buy these on EBay for half that price. Whatever way you do it, I would not even think about using unbalanced wiring however well screened, as once incorporated in the house, it can't be changed. S. -- http://audiopages.googlepages.com |
#22
Posted to rec.audio.tech
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need help choosing between line level cables
On Tue, 15 Apr 2008 13:41:20 +0100, "Serge Auckland"
wrote: "Don Pearce" wrote in message ... On Tue, 15 Apr 2008 07:52:51 -0400, "Arny Krueger" wrote: "Eeyore" wrote in message Balanced wiring only gives you an advantage if the equipment is balanced. With clever wiring it's only actually necessary for either the 'sending' or 'receiving' equipment to have a balanced input or ouput but you need to know what you're doing in this case. I know the strong advantage that balanced inputs give, but what advantage do you get from an electronically-balanced output driving an unbalanced input? Provided you have an appropriate balun, like a transformer at the input, you get all of the advantages. d -- d Yes but then you're driving a balanced input aren't you ;-) If you have an electronically balanced output (hence usually but not always referred to ground) driving an unbalanced input, I can't see what real benefit you will get however clever you are with wiring. What you use a balanced system for is to get rid of common-mode noise, usually in the form of hum, but also higher frequencies. Unbalancing at the receiving end will remove the common-mode rejection. You are right of course. Maplin have stereo audio transformers that work very transparently for isolation at under £10 apiece. http://www.maplin.co.uk/Search.aspx?...source=15&SD=Y If I were doing what the OP is doing, I would wire my house with CAT5/6 cable which is really cheap these days, then use equipment with balanced I/O. As already mentioned, CAT5/6 can carry 4 balanced audio signals, so you either get 2 stereos or a send and return stereo pair in each cable. Crosstalk isn't an issue with balanced operation. If suitable balanced equipment isn't available, then there are some alternatives. Transformers are definitely one, and they have the advantage of fully-floating operation and galvanic insulation. However, good transformers are expensive, although it's not necessary these days to have transformers which will drive 600 ohm lines, 10k-10k transformers are somewhat cheaper. Other alternatives are to get some pro units like the Henry Matchbox which lists at $225 for a bi-directional interface, therefore equivalent to 4 transformers. I would guess that the street price for the Matchbox is under $200 and as these things don't wear out, it may be possible to buy these on EBay for half that price. Whatever way you do it, I would not even think about using unbalanced wiring however well screened, as once incorporated in the house, it can't be changed. CAT5 is possibly the way to go. Are you sure about the crosstalk though? With digital signals it is only necessary to get better than about 10dB of isolation. I would want better than 90dB for audio, particularly if carrying unrelated signals. -- d |
#23
Posted to rec.audio.tech
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need help choosing between line level cables
"Don Pearce" wrote in message
... On Tue, 15 Apr 2008 13:41:20 +0100, "Serge Auckland" wrote: "Don Pearce" wrote in message ... On Tue, 15 Apr 2008 07:52:51 -0400, "Arny Krueger" wrote: "Eeyore" wrote in message Balanced wiring only gives you an advantage if the equipment is balanced. With clever wiring it's only actually necessary for either the 'sending' or 'receiving' equipment to have a balanced input or ouput but you need to know what you're doing in this case. I know the strong advantage that balanced inputs give, but what advantage do you get from an electronically-balanced output driving an unbalanced input? Provided you have an appropriate balun, like a transformer at the input, you get all of the advantages. d -- d Yes but then you're driving a balanced input aren't you ;-) If you have an electronically balanced output (hence usually but not always referred to ground) driving an unbalanced input, I can't see what real benefit you will get however clever you are with wiring. What you use a balanced system for is to get rid of common-mode noise, usually in the form of hum, but also higher frequencies. Unbalancing at the receiving end will remove the common-mode rejection. You are right of course. Maplin have stereo audio transformers that work very transparently for isolation at under £10 apiece. http://www.maplin.co.uk/Search.aspx?...source=15&SD=Y If I were doing what the OP is doing, I would wire my house with CAT5/6 cable which is really cheap these days, then use equipment with balanced I/O. As already mentioned, CAT5/6 can carry 4 balanced audio signals, so you either get 2 stereos or a send and return stereo pair in each cable. Crosstalk isn't an issue with balanced operation. If suitable balanced equipment isn't available, then there are some alternatives. Transformers are definitely one, and they have the advantage of fully-floating operation and galvanic insulation. However, good transformers are expensive, although it's not necessary these days to have transformers which will drive 600 ohm lines, 10k-10k transformers are somewhat cheaper. Other alternatives are to get some pro units like the Henry Matchbox which lists at $225 for a bi-directional interface, therefore equivalent to 4 transformers. I would guess that the street price for the Matchbox is under $200 and as these things don't wear out, it may be possible to buy these on EBay for half that price. Whatever way you do it, I would not even think about using unbalanced wiring however well screened, as once incorporated in the house, it can't be changed. CAT5 is possibly the way to go. Are you sure about the crosstalk though? With digital signals it is only necessary to get better than about 10dB of isolation. I would want better than 90dB for audio, particularly if carrying unrelated signals. -- d I haven't measured the crosstalk using CAT5 cable myself, but I know of several radio stations that use unscreened multi-twisted-pair bundles for line-level analogue audio and have no crosstalk issues(The multi-pair cables have one overall screen, but the individual pairs are unscreened.) The twisted pairs in CAT5 cable are pretty tightly twisted, and using today's low output impedance sending, (typically less than 100 ohms) I would not expect cross talk with line-level signals to be a problem. Clearly, I wouldn't use CAT5 cable for microphone feeds, but for line-level I would expect it to be fine. S. -- http://audiopages.googlepages.com |
#24
Posted to rec.audio.tech
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need help choosing between line level cables
"Kevin McMurtrie" wrote ...
$15 for Cat6 and $20 left over for balancing transformers? I don't think that would work well. Actually, growing numbers of people find it ideal. He gave links to balanced wiring. Balanced audio allows for a bit of a grounding mismatch between equipment. If his equipment supports it, balanced wiring is by far the cheapest and highest quality way to do this. 1) The OP was asking about wiring his consumer audio equipment. The likelyhood that it has balanced inputs or outputs lies somewhere between slim and none. 2) Cat5 (et.al.) *IS* balanced. In fact, it is balanced much better than most any cable sold for audio purposes. |
#25
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need help choosing between line level cables
"Don Pearce" wrote in message
On Tue, 15 Apr 2008 07:52:51 -0400, "Arny Krueger" wrote: "Eeyore" wrote in message Balanced wiring only gives you an advantage if the equipment is balanced. With clever wiring it's only actually necessary for either the 'sending' or 'receiving' equipment to have a balanced input or ouput but you need to know what you're doing in this case. I know the strong advantage that balanced inputs give, but what advantage do you get from an electronically-balanced output driving an unbalanced input? Provided you have an appropriate balun, like a transformer at the input, you get all of the advantages. The balun just turns the unbalanced input into a balanced input. Therefore, the basic answer I asked has not been answered. |
#26
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need help choosing between line level cables
On Tue, 15 Apr 2008 09:39:00 -0400, "Arny Krueger"
wrote: "Don Pearce" wrote in message On Tue, 15 Apr 2008 07:52:51 -0400, "Arny Krueger" wrote: "Eeyore" wrote in message Balanced wiring only gives you an advantage if the equipment is balanced. With clever wiring it's only actually necessary for either the 'sending' or 'receiving' equipment to have a balanced input or ouput but you need to know what you're doing in this case. I know the strong advantage that balanced inputs give, but what advantage do you get from an electronically-balanced output driving an unbalanced input? Provided you have an appropriate balun, like a transformer at the input, you get all of the advantages. The balun just turns the unbalanced input into a balanced input. Therefore, the basic answer I asked has not been answered. Ah - ok. The answer to your question is that it is impossible to drive an unbalanced input from a balanced output. The moment any part of the system is unbalanced, the whole system is unbalanced. d -- d |
#27
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need help choosing between line level cables
"Serge Auckland" wrote in
message If I were doing what the OP is doing, I would wire my house with CAT5/6 cable which is really cheap these days, then use equipment with balanced I/O. Sounds like a plan. As already mentioned, CAT5/6 can carry 4 balanced audio signals, so you either get 2 stereos or a send and return stereo pair in each cable. Crosstalk isn't an issue with balanced operation. Well, far less of an issue. Low impedance operation also favor low crosstalk. If suitable balanced equipment isn't available, then there are some alternatives. Transformers are definitely one, and they have the advantage of fully-floating operation and galvanic insulation. Agreed. However, good transformers are expensive, although it's not necessary these days to have transformers which will drive 600 ohm lines, 10k-10k transformers are somewhat cheaper. I did some tests on the pair of transformers that RS is selling as a ground isolator, for the princely sum of $16.99 or so. They turned out to be very good, especially if you keep their secondaries loaded with a few K. http://www.radioshack.com/sm-buy-the...i-2062214.html I tested Radio Shack's "Ground Isolator" 270-054 using test signals that maxed out around 2.5 v RMS. ZSource = 150 ohms, ZLoad = 10K ohms. All IM, THD, and noise artifacts were at least 80 dB down with most in the -100 dB range or better. Frequency response showed a 2 dB peak at 20 Hz and then 10 dB down at 10 Hz. There was a 3 dB peak at about 51 KHz falling to about 10 dB down around 100 KHz. +0.5 dB at 20 KHz. A little more resistive loading tames both peaks. |
#28
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need help choosing between line level cables
"Don Pearce" wrote in message
On Tue, 15 Apr 2008 09:39:00 -0400, "Arny Krueger" wrote: "Don Pearce" wrote in message On Tue, 15 Apr 2008 07:52:51 -0400, "Arny Krueger" wrote: "Eeyore" wrote in message Balanced wiring only gives you an advantage if the equipment is balanced. With clever wiring it's only actually necessary for either the 'sending' or 'receiving' equipment to have a balanced input or ouput but you need to know what you're doing in this case. I know the strong advantage that balanced inputs give, but what advantage do you get from an electronically-balanced output driving an unbalanced input? Provided you have an appropriate balun, like a transformer at the input, you get all of the advantages. The balun just turns the unbalanced input into a balanced input. Therefore, the basic answer I asked has not been answered. Ah - ok. The answer to your question is that it is impossible to drive an unbalanced input from a balanced output. Good, then I'm not losing my mind! ;-) The moment any part of the system is unbalanced, the whole system is unbalanced. As a practical matter, an unbalanced output driving a balanced input can have most of the benefits of a completely balanced system. One step up is the so-called impedance balanced output, which involves adding a single resistor to the source. That usually gives you over 90% of the benefits of a completely balanced output. |
#29
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need help choosing between line level cables
Arny Krueger wrote: "Eeyore" wrote Balanced wiring only gives you an advantage if the equipment is balanced. With clever wiring it's only actually necessary for either the 'sending' or 'receiving' equipment to have a balanced input or ouput but you need to know what you're doing in this case. I know the strong advantage that balanced inputs give, but what advantage do you get from an electronically-balanced output driving an unbalanced input? The elimination of a common ground connection that can cause circulating currents in a signal conductor in the unbalanced circuit (in the screen) because in unbalanced working the screen is used as a signal conductor as well and a voltage will be added to the signal (of magnitude RDCscreen x Iground loop). That's a circulating current as in a loop hence ground loop. The voltage added may actually be larger than that if poor internal grounding stategies have been used in the equipment under consideration due to RDC of pcb traces before the ground loop current finds it way to 'chassis earth' too. Graham |
#30
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need help choosing between line level cables
Don Pearce wrote: "Arny Krueger" wrote: "Eeyore" wrote in Balanced wiring only gives you an advantage if the equipment is balanced. With clever wiring it's only actually necessary for either the 'sending' or 'receiving' equipment to have a balanced input or ouput but you need to know what you're doing in this case. I know the strong advantage that balanced inputs give, but what advantage do you get from an electronically-balanced output driving an unbalanced input? Provided you have an appropriate balun, like a transformer at the input, you get all of the advantages. You don't even need a balun if you wire it to take advantage of the balanced output. Just take the balaned output (low/cold) to the destination input 'ground' and the output (high/hot) to the destination input and do not connect the screen at the destination. Graham |
#31
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need help choosing between line level cables
Don Pearce wrote: "Arny Krueger" wrote: The balun just turns the unbalanced input into a balanced input. Therefore, the basic answer I asked has not been answered. Ah - ok. The answer to your question is that it is impossible to drive an unbalanced input from a balanced output. The moment any part of the system is unbalanced, the whole system is unbalanced. Pure unmitigated horse manure ! See my post as to how it's done. Sadly most people don't understand balanced circuits at all. Think *differential* and it may become clearer. I recently did just what you say can't be done for an install. Much improved. Graham |
#32
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need help choosing between line level cables
Arny Krueger wrote: "Don Pearce" wrote in message Ah - ok. The answer to your question is that it is impossible to drive an unbalanced input from a balanced output. Good, then I'm not losing my mind! ;-) Don is talking CRAP unfortunately. Graham |
#33
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need help choosing between line level cables
Richard Crowley wrote: "Kevin McMurtrie" wrote ... $15 for Cat6 and $20 left over for balancing transformers? I don't think that would work well. Actually, growing numbers of people find it ideal. He gave links to balanced wiring. Balanced audio allows for a bit of a grounding mismatch between equipment. If his equipment supports it, balanced wiring is by far the cheapest and highest quality way to do this. 1) The OP was asking about wiring his consumer audio equipment. The likelyhood that it has balanced inputs or outputs lies somewhere between slim and none. I agree. OTOH it's VERY likely to be Class II equipment so the possibility of a ground loop doesn't arise unless through other equipment attached to it that does connect to the mains earth. Graham |
#34
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need help choosing between line level cables
Serge Auckland wrote: Whatever way you do it, I would not even think about using unbalanced wiring however well screened, as once incorporated in the house, it can't be changed. For little more you can run screened twin and keep your options open. That's probably the best advice. Cat 5 can cause crosstalk trouble. Graham |
#35
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need help choosing between line level cables
Serge Auckland wrote: "Don Pearce" wrote in message CAT5 is possibly the way to go. Are you sure about the crosstalk though? With digital signals it is only necessary to get better than about 10dB of isolation. I would want better than 90dB for audio, particularly if carrying unrelated signals. I haven't measured the crosstalk using CAT5 cable myself, but I know of several radio stations that use unscreened multi-twisted-pair bundles for line-level analogue audio and have no crosstalk issues. But they WILL be running balanced circuits ! I don't see Cat5 as a suitable choice here at all when ordinary screened twisted pair (balanced) cable doesn't cost a fortune. Graham |
#36
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need help choosing between line level cables
"Eeyore" wrote in message
... Don Pearce wrote: "Arny Krueger" wrote: The balun just turns the unbalanced input into a balanced input. Therefore, the basic answer I asked has not been answered. Ah - ok. The answer to your question is that it is impossible to drive an unbalanced input from a balanced output. The moment any part of the system is unbalanced, the whole system is unbalanced. Pure unmitigated horse manure ! See my post as to how it's done. Sadly most people don't understand balanced circuits at all. Think *differential* and it may become clearer. I recently did just what you say can't be done for an install. Much improved. Graham Balancing requires exactly that, that the circuits be balanced to ground:- same impedance, i.e. same capacitance, inductance etc. That, and differential inputs provides the common-mode rejection that keeps signals clean of lf (hum) and higher frequencies. A differential input that isn't balanced will have poor common-mode rejection, so although it will reduce some interference, it most probably won't do it at higher frequencies. The system you advocate won't work with equipment where the audio ground is also taken to proper ground, and therefore is dependant on the actual details of the equipment used. As far as I'm concerned, if I'm taking audio cables more than about 10 metres, I balance properly. As to the use of CAT5 cable, whilst I agree with you that potentially there is an issue with crosstalk, my experience professionally in several radio stations, is that it's perfectly acceptable. As I said in an earlier post, I have not measured the crosstalk myself, but I'm in the process of installing some audio cabling using CAT5, so I may be in a position to post some measurements later. S. -- http://audiopages.googlepages.com |
#37
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need help choosing between line level cables
On Tue, 15 Apr 2008 18:26:51 +0100, Eeyore
wrote: Arny Krueger wrote: "Don Pearce" wrote in message Ah - ok. The answer to your question is that it is impossible to drive an unbalanced input from a balanced output. Good, then I'm not losing my mind! ;-) Don is talking CRAP unfortunately. Graham Only when the following subsequent is deleted. One unbalanced connection unbalances the entire circuit. -- d |
#38
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need help choosing between line level cables
On Tue, 15 Apr 2008 18:23:49 +0100, Eeyore
wrote: Don Pearce wrote: "Arny Krueger" wrote: "Eeyore" wrote in Balanced wiring only gives you an advantage if the equipment is balanced. With clever wiring it's only actually necessary for either the 'sending' or 'receiving' equipment to have a balanced input or ouput but you need to know what you're doing in this case. I know the strong advantage that balanced inputs give, but what advantage do you get from an electronically-balanced output driving an unbalanced input? Provided you have an appropriate balun, like a transformer at the input, you get all of the advantages. You don't even need a balun if you wire it to take advantage of the balanced output. Just take the balaned output (low/cold) to the destination input 'ground' and the output (high/hot) to the destination input and do not connect the screen at the destination. Graham No longer balanced - not even a tiny bit. -- d |
#39
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need help choosing between line level cables
"Eeyore" wrote in message
... Serge Auckland wrote: "Don Pearce" wrote in message CAT5 is possibly the way to go. Are you sure about the crosstalk though? With digital signals it is only necessary to get better than about 10dB of isolation. I would want better than 90dB for audio, particularly if carrying unrelated signals. I haven't measured the crosstalk using CAT5 cable myself, but I know of several radio stations that use unscreened multi-twisted-pair bundles for line-level analogue audio and have no crosstalk issues. But they WILL be running balanced circuits ! I don't see Cat5 as a suitable choice here at all when ordinary screened twisted pair (balanced) cable doesn't cost a fortune. Graham I have assumed that the OP will run balanced, either through transformers or whatever. The beauty of CAT5 is not just the cost, but that you get two stereo circuits in one cable. That gives options like send and return, or one stereo pair with a mono cue return and a control pair, or two stereo sends. All that at a cost less than one length of screened twisted-pair. S. -- http://audiopages.googlepages.com |
#40
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need help choosing between line level cables
Don Pearce wrote: Eeyore wrote: Arny Krueger wrote: "Don Pearce" wrote in message Ah - ok. The answer to your question is that it is impossible to drive an unbalanced input from a balanced output. Good, then I'm not losing my mind! ;-) Don is talking CRAP unfortunately. Only when the following subsequent is deleted. One unbalanced connection unbalances the entire circuit. Read what I posted carefully. I AM correct. Balanced is somewhat different to differential in detail and one or the other may be equally suitable as a 'hum reducing' strategy. Graham |
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