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#1
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Mic Cable: To connect or not to connect??
Survey time. Some people say that when building a mic cable, the case
should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Your votes? Darren |
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#2
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On Sat, 15 May 2004 17:21:18 -0500, "Newsguy" wrote:
Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. The potential ground loop is *inside* the receiving electronics. Good RFI and good audio grounding practices frequently conflict. If the extra shielding obtained by grounding the shell matters to you, you already know *way* more about the topic than you ever wanted to know. Chris Hornbeck |
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#3
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On Sat, 15 May 2004 17:21:18 -0500, "Newsguy" wrote:
Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. The potential ground loop is *inside* the receiving electronics. Good RFI and good audio grounding practices frequently conflict. If the extra shielding obtained by grounding the shell matters to you, you already know *way* more about the topic than you ever wanted to know. Chris Hornbeck |
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#4
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"Newsguy" wrote ...
Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. If you want to make the connector cases grounded, then put a jumper from 1 to shell only on the female ends. That way you avoid any potential ground loops at the input to the mic preamp while shielding any inline connections. I've never grounded the cases on the XLR connectors I've made and never noticed any ill-effects from leaving them floating. If you operate in high-RF interference areas, you could try a small capacitor instead of a hard wire. |
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#5
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"Newsguy" wrote ...
Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. If you want to make the connector cases grounded, then put a jumper from 1 to shell only on the female ends. That way you avoid any potential ground loops at the input to the mic preamp while shielding any inline connections. I've never grounded the cases on the XLR connectors I've made and never noticed any ill-effects from leaving them floating. If you operate in high-RF interference areas, you could try a small capacitor instead of a hard wire. |
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#6
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Newsguy wrote:
Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Your votes? Darren I have made a lot of mic cables, and never connected pin 1 to the shell. Never had any problems. -- Eric Practice Your Mixing Skills Multi-Track Masters on CD-ROM www.Raw-Tracks.com |
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#7
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Newsguy wrote:
Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Your votes? Darren I have made a lot of mic cables, and never connected pin 1 to the shell. Never had any problems. -- Eric Practice Your Mixing Skills Multi-Track Masters on CD-ROM www.Raw-Tracks.com |
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#8
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Richard Crowley wrote:
"Newsguy" wrote ... Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. If you want to make the connector cases grounded, then put a jumper from 1 to shell only on the female ends. That way you avoid any potential ground loops at the input to the mic preamp while shielding any inline connections. How do you make a ground loop at the input of a mic preamp? That's most likely a mic, and that isn't grounded. But if you were plugging it into an output that had a ground lift, grounding the female shell would likely (depending on construction) defeat the lift. So if anything, you'd want to ground the male shell. I've never grounded the cases on the XLR connectors I've made and never noticed any ill-effects from leaving them floating. If you operate in high-RF interference areas, you could try a small capacitor instead of a hard wire. I've never seen nor made any cables with grounded shells, either. |
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#9
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Richard Crowley wrote:
"Newsguy" wrote ... Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. If you want to make the connector cases grounded, then put a jumper from 1 to shell only on the female ends. That way you avoid any potential ground loops at the input to the mic preamp while shielding any inline connections. How do you make a ground loop at the input of a mic preamp? That's most likely a mic, and that isn't grounded. But if you were plugging it into an output that had a ground lift, grounding the female shell would likely (depending on construction) defeat the lift. So if anything, you'd want to ground the male shell. I've never grounded the cases on the XLR connectors I've made and never noticed any ill-effects from leaving them floating. If you operate in high-RF interference areas, you could try a small capacitor instead of a hard wire. I've never seen nor made any cables with grounded shells, either. |
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#10
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"S O'Neill" wrote in message ... Richard Crowley wrote: "Newsguy" wrote ... Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. If you want to make the connector cases grounded, then put a jumper from 1 to shell only on the female ends. That way you avoid any potential ground loops at the input to the mic preamp while shielding any inline connections. How do you make a ground loop at the input of a mic preamp? I've seen several products that treat the pin-1 ground and the connector shell separately, and some that even treat the panel as a third part of the equation. Interesting experiments... http://www.jensentransformers.com/as/as032.pdf That's most likely a mic, and that isn't grounded. But if you were plugging it into an output that had a ground lift, grounding the female shell would likely (depending on construction) defeat the lift. So if anything, you'd want to ground the male shell. In the case of mic cables (which I'm assuming is still the topic of this thread, according to the subject line), the female end will be at the far end of the cable. I don't see how your comment abount any possible ground lift applies out there. Also assuming we are talking about runs of more than one cable length in series. For cases where a single cable connects to mic at one end and preamp/mixer at other end, this discussion is mostly academic. |
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#11
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"S O'Neill" wrote in message ... Richard Crowley wrote: "Newsguy" wrote ... Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. If you want to make the connector cases grounded, then put a jumper from 1 to shell only on the female ends. That way you avoid any potential ground loops at the input to the mic preamp while shielding any inline connections. How do you make a ground loop at the input of a mic preamp? I've seen several products that treat the pin-1 ground and the connector shell separately, and some that even treat the panel as a third part of the equation. Interesting experiments... http://www.jensentransformers.com/as/as032.pdf That's most likely a mic, and that isn't grounded. But if you were plugging it into an output that had a ground lift, grounding the female shell would likely (depending on construction) defeat the lift. So if anything, you'd want to ground the male shell. In the case of mic cables (which I'm assuming is still the topic of this thread, according to the subject line), the female end will be at the far end of the cable. I don't see how your comment abount any possible ground lift applies out there. Also assuming we are talking about runs of more than one cable length in series. For cases where a single cable connects to mic at one end and preamp/mixer at other end, this discussion is mostly academic. |
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#12
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Newsguy wrote:
Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. You can skip connecting the casing/housing IF you use the cables between boxes and IF those boxes are made correctly, but you MUST(x) connect the casing of one of the sexes if you use the cables as extension cables, and inevitably some of the time some cable will be used like that. Your votes? Connect casing/housing to cable shield in female plug only. (x) if you don't and if someone touches the housing - or the housing touches physical ground, such as a marble floor tile in a church - then there is a very real risk of hum getting induced, and the quality of the balancing, if any, will matter. Empirically determined. Darren Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
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#13
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Newsguy wrote:
Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. You can skip connecting the casing/housing IF you use the cables between boxes and IF those boxes are made correctly, but you MUST(x) connect the casing of one of the sexes if you use the cables as extension cables, and inevitably some of the time some cable will be used like that. Your votes? Connect casing/housing to cable shield in female plug only. (x) if you don't and if someone touches the housing - or the housing touches physical ground, such as a marble floor tile in a church - then there is a very real risk of hum getting induced, and the quality of the balancing, if any, will matter. Empirically determined. Darren Kind regards Peter Larsen -- ******************************************* * My site is at: http://www.muyiovatki.dk * ******************************************* |
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#14
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Darren "Newsguy" wrote:
Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Your votes? My vote is to read a two-part article by Bill Whitlock at: http://www.svconline.com/mag/avinsta...ed_interfaces/ and continued at: http://www.svconline.com/mag/avinsta..._interfaces_2/ I'm currently making a point of studying his writings and those of Neil Muncy, and I reserve the right to change my tune as I learn more. But Whitlock seems to consider it imperative to ground the shield at the "driven end" (e.g. the microphone end) of a balanced cable, and optional to do so at the output. What he seems to find really bad is connecting the shield to ground _only_ at the output end of the cable. What these people seem to find the primary cause of problems is when circuit designers--both in microphones and preamps--connect pin 1 to the audio circuit ground and only then connecting that to the chassis, instead of connecting pin 1 directly to the chassis. Now I need to figure out what this implies for phantom powering circuits. Also, I really want to build a "sniffer" (a simple device that injects interference in a way that reveals this "pin 1 problem") as described in Muncy and Whitlock's writings, and check out a bunch of gear with it. |
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#15
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Darren "Newsguy" wrote:
Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Your votes? My vote is to read a two-part article by Bill Whitlock at: http://www.svconline.com/mag/avinsta...ed_interfaces/ and continued at: http://www.svconline.com/mag/avinsta..._interfaces_2/ I'm currently making a point of studying his writings and those of Neil Muncy, and I reserve the right to change my tune as I learn more. But Whitlock seems to consider it imperative to ground the shield at the "driven end" (e.g. the microphone end) of a balanced cable, and optional to do so at the output. What he seems to find really bad is connecting the shield to ground _only_ at the output end of the cable. What these people seem to find the primary cause of problems is when circuit designers--both in microphones and preamps--connect pin 1 to the audio circuit ground and only then connecting that to the chassis, instead of connecting pin 1 directly to the chassis. Now I need to figure out what this implies for phantom powering circuits. Also, I really want to build a "sniffer" (a simple device that injects interference in a way that reveals this "pin 1 problem") as described in Muncy and Whitlock's writings, and check out a bunch of gear with it. |
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#16
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In article , Newsguy wrote:
Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Your votes? This is discussed in the FAQ. Hint: connecting just the shield on the male cables does not result in any ground loop IF the receiving gear is properly designed. Which is often not the case. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#17
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In article , Newsguy wrote:
Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Your votes? This is discussed in the FAQ. Hint: connecting just the shield on the male cables does not result in any ground loop IF the receiving gear is properly designed. Which is often not the case. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#18
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David Satz wrote:
What these people seem to find the primary cause of problems is when circuit designers--both in microphones and preamps--connect pin 1 to the audio circuit ground and only then connecting that to the chassis, instead of connecting pin 1 directly to the chassis. Now I need to figure out what this implies for phantom powering circuits. Exactly. I run into a conflicting set of ideals when working out the ground scheme for a mike preamp. On the one hand, Whilock and others recommend connecting Pin 1 directly to the chassis for ideal RFI protection. On the other hand, Pin 1 is responsible for current return in the phantom power circuit, and I really don't want 9 inches of sheet steel in series with my microphone's power suppy. The only reasonable solution seems to be making Pin 1 "the" point where circuit ground meets chassis ground, which isn't really possible if you also have an internal power supply (where the safety ground has that same requirement) and/or in a 2-channel preamp. You end up having more than one connection between chassis and circuit ground. I think it's not too big a deal though, provided each of those ground connectionss are short and direct, and as thick and beefy as possible so that the inevitable loop is small in area and low in impedance. Am I missing anything? ulysses |
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#19
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David Satz wrote:
What these people seem to find the primary cause of problems is when circuit designers--both in microphones and preamps--connect pin 1 to the audio circuit ground and only then connecting that to the chassis, instead of connecting pin 1 directly to the chassis. Now I need to figure out what this implies for phantom powering circuits. Exactly. I run into a conflicting set of ideals when working out the ground scheme for a mike preamp. On the one hand, Whilock and others recommend connecting Pin 1 directly to the chassis for ideal RFI protection. On the other hand, Pin 1 is responsible for current return in the phantom power circuit, and I really don't want 9 inches of sheet steel in series with my microphone's power suppy. The only reasonable solution seems to be making Pin 1 "the" point where circuit ground meets chassis ground, which isn't really possible if you also have an internal power supply (where the safety ground has that same requirement) and/or in a 2-channel preamp. You end up having more than one connection between chassis and circuit ground. I think it's not too big a deal though, provided each of those ground connectionss are short and direct, and as thick and beefy as possible so that the inevitable loop is small in area and low in impedance. Am I missing anything? ulysses |
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#21
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#22
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#23
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#24
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In article ,
MacKerr wrote: n article writes: Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Connect the shield to pin 1 on both ends. BRBR I think the question was about connecting the connector body to pin 1, not the shield. The shield should be connected on both ends, the connector ground lug should not be connected. If you don't connect the connector ground lug at all, then each junction between cables (when you chain cables together) is unshielded. This is bad. If you connect all connector ground lugs, then each junction between cables is a ground loop. This is bad. If you connect only the female connector ground lugs, than each junction is properly shielded, and the equipment that the male end is plugged into is fine, but the equipment that the female end is plugged into might now have a ground loop because pin 1 is already tied to the case inside. This is bad. Unless it's a Neumann product, in which case you HAVE to have pin 1 tied to the shield on the female end, because pin 1 is not otherwise tied to the case inside. Leaving it disconnected is bad. Is this confusing enough? This is really a horrible can of worms and it can lead to some serious hair-pulling out in high RFI environments where even tiny loops are problematic. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#25
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In article ,
MacKerr wrote: n article writes: Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Connect the shield to pin 1 on both ends. BRBR I think the question was about connecting the connector body to pin 1, not the shield. The shield should be connected on both ends, the connector ground lug should not be connected. If you don't connect the connector ground lug at all, then each junction between cables (when you chain cables together) is unshielded. This is bad. If you connect all connector ground lugs, then each junction between cables is a ground loop. This is bad. If you connect only the female connector ground lugs, than each junction is properly shielded, and the equipment that the male end is plugged into is fine, but the equipment that the female end is plugged into might now have a ground loop because pin 1 is already tied to the case inside. This is bad. Unless it's a Neumann product, in which case you HAVE to have pin 1 tied to the shield on the female end, because pin 1 is not otherwise tied to the case inside. Leaving it disconnected is bad. Is this confusing enough? This is really a horrible can of worms and it can lead to some serious hair-pulling out in high RFI environments where even tiny loops are problematic. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#26
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"Scott Dorsey" wrote in message ... In article , MacKerr wrote: n article writes: Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Connect the shield to pin 1 on both ends. BRBR I think the question was about connecting the connector body to pin 1, not the shield. The shield should be connected on both ends, the connector ground lug should not be connected. If you don't connect the connector ground lug at all, then each junction between cables (when you chain cables together) is unshielded. This is bad. If you connect all connector ground lugs, then each junction between cables is a ground loop. This is bad. If you connect only the female connector ground lugs, than each junction is properly shielded, and the equipment that the male end is plugged into is fine, but the equipment that the female end is plugged into might now have a ground loop because pin 1 is already tied to the case inside. This is bad. Unless it's a Neumann product, in which case you HAVE to have pin 1 tied to the shield on the female end, because pin 1 is not otherwise tied to the case inside. Leaving it disconnected is bad. Is this confusing enough? This is really a horrible can of worms and it can lead to some serious hair-pulling out in high RFI environments where even tiny loops are problematic. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." Hi Scott. I think I should have been more clear when I asked my original question, so here goes: When I built the cable, I connected the shield to pin 1 on both ends (Male and Female) of the XLR. This of course is standard practice. My question is, now that I have this done, do I go a step further and ground pin 1 to the xlr shell? Darren |
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#27
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"Scott Dorsey" wrote in message ... In article , MacKerr wrote: n article writes: Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Connect the shield to pin 1 on both ends. BRBR I think the question was about connecting the connector body to pin 1, not the shield. The shield should be connected on both ends, the connector ground lug should not be connected. If you don't connect the connector ground lug at all, then each junction between cables (when you chain cables together) is unshielded. This is bad. If you connect all connector ground lugs, then each junction between cables is a ground loop. This is bad. If you connect only the female connector ground lugs, than each junction is properly shielded, and the equipment that the male end is plugged into is fine, but the equipment that the female end is plugged into might now have a ground loop because pin 1 is already tied to the case inside. This is bad. Unless it's a Neumann product, in which case you HAVE to have pin 1 tied to the shield on the female end, because pin 1 is not otherwise tied to the case inside. Leaving it disconnected is bad. Is this confusing enough? This is really a horrible can of worms and it can lead to some serious hair-pulling out in high RFI environments where even tiny loops are problematic. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." Hi Scott. I think I should have been more clear when I asked my original question, so here goes: When I built the cable, I connected the shield to pin 1 on both ends (Male and Female) of the XLR. This of course is standard practice. My question is, now that I have this done, do I go a step further and ground pin 1 to the xlr shell? Darren |
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#28
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In article , Newsguy wrote:
"Scott Dorsey" wrote in message ... In article , MacKerr wrote: n article writes: Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Connect the shield to pin 1 on both ends. BRBR I think the question was about connecting the connector body to pin 1, not the shield. The shield should be connected on both ends, the connector ground lug should not be connected. If you don't connect the connector ground lug at all, then each junction between cables (when you chain cables together) is unshielded. This is bad. If you connect all connector ground lugs, then each junction between cables is a ground loop. This is bad. If you connect only the female connector ground lugs, than each junction is properly shielded, and the equipment that the male end is plugged into is fine, but the equipment that the female end is plugged into might now have a ground loop because pin 1 is already tied to the case inside. This is bad. Unless it's a Neumann product, in which case you HAVE to have pin 1 tied to the shield on the female end, because pin 1 is not otherwise tied to the case inside. Leaving it disconnected is bad. Is this confusing enough? This is really a horrible can of worms and it can lead to some serious hair-pulling out in high RFI environments where even tiny loops are problematic. Hi Scott. I think I should have been more clear when I asked my original question, so here goes: When I built the cable, I connected the shield to pin 1 on both ends (Male and Female) of the XLR. This of course is standard practice. My question is, now that I have this done, do I go a step further and ground pin 1 to the xlr shell? Sadly, that depends on what you're plugging it into. You _may_ want to ground pin 1 of the FEMALE connector only to the shell. Then again, you may not. See above. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#29
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In article , Newsguy wrote:
"Scott Dorsey" wrote in message ... In article , MacKerr wrote: n article writes: Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Connect the shield to pin 1 on both ends. BRBR I think the question was about connecting the connector body to pin 1, not the shield. The shield should be connected on both ends, the connector ground lug should not be connected. If you don't connect the connector ground lug at all, then each junction between cables (when you chain cables together) is unshielded. This is bad. If you connect all connector ground lugs, then each junction between cables is a ground loop. This is bad. If you connect only the female connector ground lugs, than each junction is properly shielded, and the equipment that the male end is plugged into is fine, but the equipment that the female end is plugged into might now have a ground loop because pin 1 is already tied to the case inside. This is bad. Unless it's a Neumann product, in which case you HAVE to have pin 1 tied to the shield on the female end, because pin 1 is not otherwise tied to the case inside. Leaving it disconnected is bad. Is this confusing enough? This is really a horrible can of worms and it can lead to some serious hair-pulling out in high RFI environments where even tiny loops are problematic. Hi Scott. I think I should have been more clear when I asked my original question, so here goes: When I built the cable, I connected the shield to pin 1 on both ends (Male and Female) of the XLR. This of course is standard practice. My question is, now that I have this done, do I go a step further and ground pin 1 to the xlr shell? Sadly, that depends on what you're plugging it into. You _may_ want to ground pin 1 of the FEMALE connector only to the shell. Then again, you may not. See above. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#30
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I have no noise in my system with all cables' shields connected at both
ends. I say connect Pin 1 at both ends unless you have a specific need to lift it. If you connect the cases, you are sure to end up with a ground loop someplace. If you don't connect the cases, and you connect two cables together, then yes, you will have a tiny area where the conductors are unshielded. Unless you are in some really hellish RF or EMI environment, this won't matter a bit. "Scott Dorsey" wrote in message ... In article , Newsguy wrote: "Scott Dorsey" wrote in message ... In article , MacKerr wrote: n article writes: Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Connect the shield to pin 1 on both ends. BRBR I think the question was about connecting the connector body to pin 1, not the shield. The shield should be connected on both ends, the connector ground lug should not be connected. If you don't connect the connector ground lug at all, then each junction between cables (when you chain cables together) is unshielded. This is bad. If you connect all connector ground lugs, then each junction between cables is a ground loop. This is bad. If you connect only the female connector ground lugs, than each junction is properly shielded, and the equipment that the male end is plugged into is fine, but the equipment that the female end is plugged into might now have a ground loop because pin 1 is already tied to the case inside. This is bad. Unless it's a Neumann product, in which case you HAVE to have pin 1 tied to the shield on the female end, because pin 1 is not otherwise tied to the case inside. Leaving it disconnected is bad. Is this confusing enough? This is really a horrible can of worms and it can lead to some serious hair-pulling out in high RFI environments where even tiny loops are problematic. Hi Scott. I think I should have been more clear when I asked my original question, so here goes: When I built the cable, I connected the shield to pin 1 on both ends (Male and Female) of the XLR. This of course is standard practice. My question is, now that I have this done, do I go a step further and ground pin 1 to the xlr shell? Sadly, that depends on what you're plugging it into. You _may_ want to ground pin 1 of the FEMALE connector only to the shell. Then again, you may not. See above. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#31
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I have no noise in my system with all cables' shields connected at both
ends. I say connect Pin 1 at both ends unless you have a specific need to lift it. If you connect the cases, you are sure to end up with a ground loop someplace. If you don't connect the cases, and you connect two cables together, then yes, you will have a tiny area where the conductors are unshielded. Unless you are in some really hellish RF or EMI environment, this won't matter a bit. "Scott Dorsey" wrote in message ... In article , Newsguy wrote: "Scott Dorsey" wrote in message ... In article , MacKerr wrote: n article writes: Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Connect the shield to pin 1 on both ends. BRBR I think the question was about connecting the connector body to pin 1, not the shield. The shield should be connected on both ends, the connector ground lug should not be connected. If you don't connect the connector ground lug at all, then each junction between cables (when you chain cables together) is unshielded. This is bad. If you connect all connector ground lugs, then each junction between cables is a ground loop. This is bad. If you connect only the female connector ground lugs, than each junction is properly shielded, and the equipment that the male end is plugged into is fine, but the equipment that the female end is plugged into might now have a ground loop because pin 1 is already tied to the case inside. This is bad. Unless it's a Neumann product, in which case you HAVE to have pin 1 tied to the shield on the female end, because pin 1 is not otherwise tied to the case inside. Leaving it disconnected is bad. Is this confusing enough? This is really a horrible can of worms and it can lead to some serious hair-pulling out in high RFI environments where even tiny loops are problematic. Hi Scott. I think I should have been more clear when I asked my original question, so here goes: When I built the cable, I connected the shield to pin 1 on both ends (Male and Female) of the XLR. This of course is standard practice. My question is, now that I have this done, do I go a step further and ground pin 1 to the xlr shell? Sadly, that depends on what you're plugging it into. You _may_ want to ground pin 1 of the FEMALE connector only to the shell. Then again, you may not. See above. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#32
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Tim Padrick wrote:
I have no noise in my system with all cables' shields connected at both ends. I say connect Pin 1 at both ends unless you have a specific need to lift it. If you connect the cases, you are sure to end up with a ground loop someplace. If you don't connect the cases, and you connect two cables together, then yes, you will have a tiny area where the conductors are unshielded. Unless you are in some really hellish RF or EMI environment, this won't matter a bit. Unless you are in a really hellish RF environment, none of this will matter a bit. You can connect it either way and it won't make a bit of difference. The problem is that sooner or later, you will be in a hellish RF environment. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#33
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Tim Padrick wrote:
I have no noise in my system with all cables' shields connected at both ends. I say connect Pin 1 at both ends unless you have a specific need to lift it. If you connect the cases, you are sure to end up with a ground loop someplace. If you don't connect the cases, and you connect two cables together, then yes, you will have a tiny area where the conductors are unshielded. Unless you are in some really hellish RF or EMI environment, this won't matter a bit. Unless you are in a really hellish RF environment, none of this will matter a bit. You can connect it either way and it won't make a bit of difference. The problem is that sooner or later, you will be in a hellish RF environment. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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#34
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Darren ("Newsguy") wrote:
Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Your votes? I'm not angling for a second vote, but would simply like to point out that ground loops are the rule rather than the exception when audio components are connected together. Some current will almost always flow in the shield, and not just clean DC, either. The point is to avoid channeling it into your audio circuitry--and that depends on the equipment design more than on the cable. Well-designed balanced inputs and outputs should allow audio components to function properly despite their almost inevitable differences in ground reference levels. --best regards |
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#35
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Darren ("Newsguy") wrote:
Survey time. Some people say that when building a mic cable, the case should be connected to Pin 1. Some say this introduces a ground loop and causes problems. Your votes? I'm not angling for a second vote, but would simply like to point out that ground loops are the rule rather than the exception when audio components are connected together. Some current will almost always flow in the shield, and not just clean DC, either. The point is to avoid channeling it into your audio circuitry--and that depends on the equipment design more than on the cable. Well-designed balanced inputs and outputs should allow audio components to function properly despite their almost inevitable differences in ground reference levels. --best regards |
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