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Post by tonycamphd on Jul 2, 2014 8:40:20 GMT -6
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Post by svart on Jul 2, 2014 8:42:45 GMT -6
I get a 404 from that link.
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Post by tonycamphd on Jul 2, 2014 8:49:00 GMT -6
I get a 404 from that link. I believe it's fixed? Let me know
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Post by svart on Jul 2, 2014 9:13:22 GMT -6
Yep! that works.
Thanks.
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Post by matt on Jul 2, 2014 10:20:43 GMT -6
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Post by mulmany on Jul 2, 2014 19:29:30 GMT -6
Well this article explains why the Belden 9182 or the General equivalent has such good noise specs. If i understand it completely!
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Post by tonycamphd on Jul 13, 2014 9:45:23 GMT -6
this thread should be hovering around the top for a while imo, this is the kind of stuff that helps remove the voodoo aspects from pro audio, i think everyone should try to wrap their head around it, i'm reading through it yet again.... here's an interesting snip that corroborates what jim said about the belden cable ridding low level grunge.. up to 24db!!! over a few tracks, that is waaaaaaaay more than subtle hair splitting.
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Post by btreim on Jul 14, 2014 14:50:07 GMT -6
Nice article. This is going to take a couple read through for sure. Thanks, tonycamphd!
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ericn
Temp
Balance Engineer
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Post by ericn on Jul 14, 2014 19:33:59 GMT -6
Not to go to far on a tangent, but anybody know anybody who has a Studio tech services modded Digi 192? Price looks nice! But the proof is in the pudding!
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Post by tonycamphd on Jul 14, 2014 19:50:25 GMT -6
Not to go to far on a tangent, but anybody know anybody who has a Studio tech services modded Digi 192? Price looks nice! But the proof is in the pudding! link?
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ericn
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Balance Engineer
Posts: 14,967
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Post by ericn on Jul 14, 2014 19:59:27 GMT -6
Not to go to far on a tangent, but anybody know anybody who has a Studio tech services modded Digi 192? Price looks nice! But the proof is in the pudding! link? Man I thought I put this in Kennedy's DAC thread! I'd say I'm all thumbs but I just one is enough problems! But here it is! www.studio-techservices.com/E%3DMB2/HD192_Audio_Modification.html
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Post by tonycamphd on Jul 14, 2014 20:03:17 GMT -6
digi 192 mods, ground loops....? close enough for the girls i date 8)
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ericn
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Balance Engineer
Posts: 14,967
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Post by ericn on Jul 14, 2014 20:12:29 GMT -6
Tony that's why I went 192 digital and Panasonic Ramsa ! None of the issues I have had with regular Digi boxes! Lifting aground on a DSUB is soooooo much fun!
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Post by svart on Jul 15, 2014 8:43:39 GMT -6
I'm gonna throw this out there again.. You should never have to lift a ground. Grounds are there for a purpose, which is mostly protecting you from shocks and to a lesser extent, shielding the signals from noise ingress.
Lifting a ground to get rid of a problem is just putting a band-aid on a gunshot, there are bigger issues at hand.
Similarly, requiring the use of isolating transformers and things of that nature to get rid of circulating currents (AKA ground loops) is also treating a symptom of a larger problem, but not treating the problem itself.
The issue is always that there is a larger current flowing through a ground that it should not be flowing through at that potential. In other words, the bulk of the ground return current is going the wrong way.
As I've gotten used to saying in the RF design world.. "When is ground not ground? Because it's not!" (It's a lot more hilarious to use on a new engineer and see their faces after they realize what they've gotten into..)
It's unfortunate that most folks misunderstand grounding and decoupling theory. Ground is never ZERO. Return currents that aren't turned into heat by the devices match ALL of the currents being fed into the system. Since your body is generally at "ground" potential, you don't get shocked from "ground", but make no mistake, it's just as alive with currents as the V+ you power the device with.
Because of this, ground reacts the same ways you'd expect any supply current to act, including flowing through the path of least resistance/impedance. In a design that has poor grounding or poor layout that causes a condition where the ground path is higher impedance than those devices connected to it, the currents will flow through all ground attachments, including those signal shields that were never meant to handle those types of currents. When this happens, you have the familiar buzzing and strange anomalies related to the "ground loop".
Again, the cause is that one or more devices are designed poorly or have bad connections on the inside or outside. There is no such thing as ground loops being "normal" or "expected". The only fix for ground current problems is to fix the ground conductor issues. It should always be the lowest impedance conductor in the system. It doesn't matter if it's the heaviest ground plane on a PCB, or the largest wire in the box, or the chassis itself, the ground should be the lowest impedance conductor. I can't tell you how many "pro" designs I've seen where the ground for a part or section of PCB was a tiny little trace.
Case in point.. A few years ago when I set up the studio at the new place, I installed new patch bay systems and also installed the recording computer into a new rack chassis. After nearly 2 weeks of soldering almost 1500 solder joints, I powered everything on to find a -50db buzz.
The only way to find this type of thing is to meticulously unplug things in an attempt to narrow down the culprits. I eventually found that unpluggin the data cable connection between the SSL Alphalink and the recording computer stopped the buzzing. So, I disassembled the computer to see if I had installed anything poorly. I had not. Another test showed the buzz was just as bad, so I took the computer back apart to look again..
And I noticed that the panels of the rack chassis were all painted, inside and out. Each panel that was riveted together had paint covering the areas where the panels joined. BAM. The chassis grounding was shit. I drilled out all the rivets and proceeded to sand all the places where the panels touched. I riveted it back together and reinstalled everything.
Plugged it back in and booted up to a -90db noise floor. I dropped 40db of noise by fixing the chassis of the computer so that the ground currents flowed through the chassis and power supply rather than attempting to ground from the motherboard through the DSP card to the Alphalink.
That's how you fix ground current loops.
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Post by tonycamphd on Jul 15, 2014 9:46:17 GMT -6
I'm gonna throw this out there again.. You should never have to lift a ground. Grounds are there for a purpose, which is mostly protecting you from shocks and to a lesser extent, shielding the signals from noise ingress. Lifting a ground to get rid of a problem is just putting a band-aid on a gunshot, there are bigger issues at hand. Similarly, requiring the use of isolating transformers and things of that nature to get rid of circulating currents (AKA ground loops) is also treating a symptom of a larger problem, but not treating the problem itself. The issue is always that there is a larger current flowing through a ground that it should not be flowing through at that potential. In other words, the bulk of the ground return current is going the wrong way. As I've gotten used to saying in the RF design world.. "When is ground not ground? Because it's not!" (It's a lot more hilarious to use on a new engineer and see their faces after they realize what they've gotten into..) It's unfortunate that most folks misunderstand grounding and decoupling theory. Ground is never ZERO. Return currents that aren't turned into heat by the devices match ALL of the currents being fed into the system. Since your body is generally at "ground" potential, you don't get shocked from "ground", but make no mistake, it's just as alive with currents as the V+ you power the device with. Because of this, ground reacts the same ways you'd expect any supply current to act, including flowing through the path of least resistance/impedance. In a design that has poor grounding or poor layout that causes a condition where the ground path is higher impedance than those devices connected to it, the currents will flow through all ground attachments, including those signal shields that were never meant to handle those types of currents. When this happens, you have the familiar buzzing and strange anomalies related to the "ground loop". Again, the cause is that one or more devices are designed poorly or have bad connections on the inside or outside. There is no such thing as ground loops being "normal" or "expected". The only fix for ground current problems is to fix the ground conductor issues. It should always be the lowest impedance conductor in the system. It doesn't matter if it's the heaviest ground plane on a PCB, or the largest wire in the box, or the chassis itself, the ground should be the lowest impedance conductor. I can't tell you how many "pro" designs I've seen where the ground for a part or section of PCB was a tiny little trace. Case in point.. A few years ago when I set up the studio at the new place, I installed new patch bay systems and also installed the recording computer into a new rack chassis. After nearly 2 weeks of soldering almost 1500 solder joints, I powered everything on to find a -50db buzz. The only way to find this type of thing is to meticulously unplug things in an attempt to narrow down the culprits. I eventually found that unpluggin the data cable connection between the SSL Alphalink and the recording computer stopped the buzzing. So, I disassembled the computer to see if I had installed anything poorly. I had not. Another test showed the buzz was just as bad, so I took the computer back apart to look again.. And I noticed that the panels of the rack chassis were all painted, inside and out. Each panel that was riveted together had paint covering the areas where the panels joined. BAM. The chassis grounding was shit. I drilled out all the rivets and proceeded to sand all the places where the panels touched. I riveted it back together and reinstalled everything. Plugged it back in and booted up to a -90db noise floor. I dropped 40db of noise by fixing the chassis of the computer so that the ground currents flowed through the chassis and power supply rather than attempting to ground from the motherboard through the DSP card to the Alphalink. That's how you fix ground current loops. nice! gretat stuff, the only thing i would add is, your problem would've been avoided all together if you had just purchased a superior MACPRO to begin with... sorry, couldn't resist bro...
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ericn
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Posts: 14,967
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Post by ericn on Jul 15, 2014 9:55:26 GMT -6
I'm gonna throw this out there again.. You should never have to lift a ground. Grounds are there for a purpose, which is mostly protecting you from shocks and to a lesser extent, shielding the signals from noise ingress. Lifting a ground to get rid of a problem is just putting a band-aid on a gunshot, there are bigger issues at hand. Similarly, requiring the use of isolating transformers and things of that nature to get rid of circulating currents (AKA ground loops) is also treating a symptom of a larger problem, but not treating the problem itself. The issue is always that there is a larger current flowing through a ground that it should not be flowing through at that potential. In other words, the bulk of the ground return current is going the wrong way. As I've gotten used to saying in the RF design world.. "When is ground not ground? Because it's not!" (It's a lot more hilarious to use on a new engineer and see their faces after they realize what they've gotten into..) It's unfortunate that most folks misunderstand grounding and decoupling theory. Ground is never ZERO. Return currents that aren't turned into heat by the devices match ALL of the currents being fed into the system. Since your body is generally at "ground" potential, you don't get shocked from "ground", but make no mistake, it's just as alive with currents as the V+ you power the device with. Because of this, ground reacts the same ways you'd expect any supply current to act, including flowing through the path of least resistance/impedance. In a design that has poor grounding or poor layout that causes a condition where the ground path is higher impedance than those devices connected to it, the currents will flow through all ground attachments, including those signal shields that were never meant to handle those types of currents. When this happens, you have the familiar buzzing and strange anomalies related to the "ground loop". Again, the cause is that one or more devices are designed poorly or have bad connections on the inside or outside. There is no such thing as ground loops being "normal" or "expected". The only fix for ground current problems is to fix the ground conductor issues. It should always be the lowest impedance conductor in the system. It doesn't matter if it's the heaviest ground plane on a PCB, or the largest wire in the box, or the chassis itself, the ground should be the lowest impedance conductor. I can't tell you how many "pro" designs I've seen where the ground for a part or section of PCB was a tiny little trace. Case in point.. A few years ago when I set up the studio at the new place, I installed new patch bay systems and also installed the recording computer into a new rack chassis. After nearly 2 weeks of soldering almost 1500 solder joints, I powered everything on to find a -50db buzz. The only way to find this type of thing is to meticulously unplug things in an attempt to narrow down the culprits. I eventually found that unpluggin the data cable connection between the SSL Alphalink and the recording computer stopped the buzzing. So, I disassembled the computer to see if I had installed anything poorly. I had not. Another test showed the buzz was just as bad, so I took the computer back apart to look again.. And I noticed that the panels of the rack chassis were all painted, inside and out. Each panel that was riveted together had paint covering the areas where the panels joined. BAM. The chassis grounding was shit. I drilled out all the rivets and proceeded to sand all the places where the panels touched. I riveted it back together and reinstalled everything. Plugged it back in and booted up to a -90db noise floor. I dropped 40db of noise by fixing the chassis of the computer so that the ground currents flowed through the chassis and power supply rather than attempting to ground from the motherboard through the DSP card to the Alphalink. That's how you fix ground current loops. I agree, But to often in the real world budget / client desire / time leads us to a quick "treat and street" mentality ! No matter how much that Hummmmmm annoys people getting them to put out the cash / effort never happens.
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Post by btreim on Jul 15, 2014 10:00:26 GMT -6
I'm gonna throw this out there again.. You should never have to lift a ground. Grounds are there for a purpose, which is mostly protecting you from shocks and to a lesser extent, shielding the signals from noise ingress. Lifting a ground to get rid of a problem is just putting a band-aid on a gunshot, there are bigger issues at hand. Similarly, requiring the use of isolating transformers and things of that nature to get rid of circulating currents (AKA ground loops) is also treating a symptom of a larger problem, but not treating the problem itself. The issue is always that there is a larger current flowing through a ground that it should not be flowing through at that potential. In other words, the bulk of the ground return current is going the wrong way. As I've gotten used to saying in the RF design world.. "When is ground not ground? Because it's not!" (It's a lot more hilarious to use on a new engineer and see their faces after they realize what they've gotten into..) It's unfortunate that most folks misunderstand grounding and decoupling theory. Ground is never ZERO. Return currents that aren't turned into heat by the devices match ALL of the currents being fed into the system. Since your body is generally at "ground" potential, you don't get shocked from "ground", but make no mistake, it's just as alive with currents as the V+ you power the device with. Because of this, ground reacts the same ways you'd expect any supply current to act, including flowing through the path of least resistance/impedance. In a design that has poor grounding or poor layout that causes a condition where the ground path is higher impedance than those devices connected to it, the currents will flow through all ground attachments, including those signal shields that were never meant to handle those types of currents. When this happens, you have the familiar buzzing and strange anomalies related to the "ground loop". Again, the cause is that one or more devices are designed poorly or have bad connections on the inside or outside. There is no such thing as ground loops being "normal" or "expected". The only fix for ground current problems is to fix the ground conductor issues. It should always be the lowest impedance conductor in the system. It doesn't matter if it's the heaviest ground plane on a PCB, or the largest wire in the box, or the chassis itself, the ground should be the lowest impedance conductor. I can't tell you how many "pro" designs I've seen where the ground for a part or section of PCB was a tiny little trace. Case in point.. A few years ago when I set up the studio at the new place, I installed new patch bay systems and also installed the recording computer into a new rack chassis. After nearly 2 weeks of soldering almost 1500 solder joints, I powered everything on to find a -50db buzz. The only way to find this type of thing is to meticulously unplug things in an attempt to narrow down the culprits. I eventually found that unpluggin the data cable connection between the SSL Alphalink and the recording computer stopped the buzzing. So, I disassembled the computer to see if I had installed anything poorly. I had not. Another test showed the buzz was just as bad, so I took the computer back apart to look again.. And I noticed that the panels of the rack chassis were all painted, inside and out. Each panel that was riveted together had paint covering the areas where the panels joined. BAM. The chassis grounding was shit. I drilled out all the rivets and proceeded to sand all the places where the panels touched. I riveted it back together and reinstalled everything. Plugged it back in and booted up to a -90db noise floor. I dropped 40db of noise by fixing the chassis of the computer so that the ground currents flowed through the chassis and power supply rather than attempting to ground from the motherboard through the DSP card to the Alphalink. That's how you fix ground current loops. I feel like most people I see lifting ground are usually dealing with guitar amps & pedal boards. Myself included. Your average amp is going to be a balanced connection, and your average pedal board power supply (like a 1spot) is going to be unbalanced. Or, without a safety ground. My very basic understanding after reading the article was that you could put some sort of input isolating transformer right before the input of the amp instead of lifting ground on the amp. I'm sure I'm way off base, what would be the correct way to go about it?
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Post by tonycamphd on Jul 15, 2014 10:47:07 GMT -6
I'm gonna throw this out there again.. You should never have to lift a ground. Grounds are there for a purpose, which is mostly protecting you from shocks and to a lesser extent, shielding the signals from noise ingress. Lifting a ground to get rid of a problem is just putting a band-aid on a gunshot, there are bigger issues at hand. Similarly, requiring the use of isolating transformers and things of that nature to get rid of circulating currents (AKA ground loops) is also treating a symptom of a larger problem, but not treating the problem itself. The issue is always that there is a larger current flowing through a ground that it should not be flowing through at that potential. In other words, the bulk of the ground return current is going the wrong way. As I've gotten used to saying in the RF design world.. "When is ground not ground? Because it's not!" (It's a lot more hilarious to use on a new engineer and see their faces after they realize what they've gotten into..) It's unfortunate that most folks misunderstand grounding and decoupling theory. Ground is never ZERO. Return currents that aren't turned into heat by the devices match ALL of the currents being fed into the system. Since your body is generally at "ground" potential, you don't get shocked from "ground", but make no mistake, it's just as alive with currents as the V+ you power the device with. Because of this, ground reacts the same ways you'd expect any supply current to act, including flowing through the path of least resistance/impedance. In a design that has poor grounding or poor layout that causes a condition where the ground path is higher impedance than those devices connected to it, the currents will flow through all ground attachments, including those signal shields that were never meant to handle those types of currents. When this happens, you have the familiar buzzing and strange anomalies related to the "ground loop". Again, the cause is that one or more devices are designed poorly or have bad connections on the inside or outside. There is no such thing as ground loops being "normal" or "expected". The only fix for ground current problems is to fix the ground conductor issues. It should always be the lowest impedance conductor in the system. It doesn't matter if it's the heaviest ground plane on a PCB, or the largest wire in the box, or the chassis itself, the ground should be the lowest impedance conductor. I can't tell you how many "pro" designs I've seen where the ground for a part or section of PCB was a tiny little trace. Case in point.. A few years ago when I set up the studio at the new place, I installed new patch bay systems and also installed the recording computer into a new rack chassis. After nearly 2 weeks of soldering almost 1500 solder joints, I powered everything on to find a -50db buzz. The only way to find this type of thing is to meticulously unplug things in an attempt to narrow down the culprits. I eventually found that unpluggin the data cable connection between the SSL Alphalink and the recording computer stopped the buzzing. So, I disassembled the computer to see if I had installed anything poorly. I had not. Another test showed the buzz was just as bad, so I took the computer back apart to look again.. And I noticed that the panels of the rack chassis were all painted, inside and out. Each panel that was riveted together had paint covering the areas where the panels joined. BAM. The chassis grounding was shit. I drilled out all the rivets and proceeded to sand all the places where the panels touched. I riveted it back together and reinstalled everything. Plugged it back in and booted up to a -90db noise floor. I dropped 40db of noise by fixing the chassis of the computer so that the ground currents flowed through the chassis and power supply rather than attempting to ground from the motherboard through the DSP card to the Alphalink. That's how you fix ground current loops. I feel like most people I see lifting ground are usually dealing with guitar amps & pedal boards. Myself included. Your average amp is going to be a balanced connection, and your average pedal board power supply (like a 1spot) is going to be unbalanced. Or, without a safety ground. My very basic understanding after reading the article was that you could put some sort of input isolating transformer right before the input of the amp instead of lifting ground on the amp. I'm sure I'm way off base, what would be the correct way to go about it? this is one of the most dangerous things you can do, tube circuits have obnoxious amounts of lethal DC voltage, if it finds it's way to you as its ground, bye bye. google guitar electrocucion deaths
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Post by svart on Jul 15, 2014 11:03:36 GMT -6
I feel like most people I see lifting ground are usually dealing with guitar amps & pedal boards. Myself included. Your average amp is going to be a balanced connection, and your average pedal board power supply (like a 1spot) is going to be unbalanced. Or, without a safety ground. My very basic understanding after reading the article was that you could put some sort of input isolating transformer right before the input of the amp instead of lifting ground on the amp. I'm sure I'm way off base, what would be the correct way to go about it? I'm not sure what you mean by "balanced" amp here.. Do you mean differential I/O on preamps and such? The power shouldn't matter. Neither should being balanced, differential or single-ended. What usually happens in these situations is that pedals and things are built cheaply and usually without regard to being the lowest noise devices, so some of their unrectified AC gets back on the ground system, or simply hums through the amp. It's best to just figure out a way to condition the DC power to the pedals if possible, since the pedals themselves rarely have enough decoupling built into them to be totally hum free. In a guitar amp, the ground should be going to the chassis. The neutral and hot should go to the power transformer. After rectification, the 0V side of the rectifiers is referenced to the earth/chassis ground. IF there is a proper amount of decoupling for the circuit, then there should be no significant AC noise on the earth/chassis ground. IF you were to lift ground on a 3 wire guitar amp (which shouldn't be able to happen), then the "ground" can float upwards as the line voltage fluctuates, and you can get shocked as Tony was saying.
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Post by btreim on Jul 15, 2014 11:27:46 GMT -6
I'm not sure what you mean by "balanced" amp here.. Do you mean differential I/O on preamps and such? The power shouldn't matter. Neither should being balanced, differential or single-ended. What usually happens in these situations is that pedals and things are built cheaply and usually without regard to being the lowest noise devices, so some of their unrectified AC gets back on the ground system, or simply hums through the amp. It's best to just figure out a way to condition the DC power to the pedals if possible, since the pedals themselves rarely have enough decoupling built into them to be totally hum free. In a guitar amp, the ground should be going to the chassis. The neutral and hot should go to the power transformer. After rectification, the 0V side of the rectifiers is referenced to the earth/chassis ground. IF there is a proper amount of decoupling for the circuit, then there should be no significant AC noise on the earth/chassis ground. IF you were to lift ground on a 3 wire guitar amp (which shouldn't be able to happen), then the "ground" can float upwards as the line voltage fluctuates, and you can get shocked as Tony was saying. I was probably using "balanced" in the wrong context. I was talking about a three prong AC plug. Thanks for the great info svart and tonycamphd. Learned some very valuable info and cleared up some major misconceptions from this article.
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Post by svart on Jul 15, 2014 12:23:21 GMT -6
I'm not sure what you mean by "balanced" amp here.. Do you mean differential I/O on preamps and such? The power shouldn't matter. Neither should being balanced, differential or single-ended. What usually happens in these situations is that pedals and things are built cheaply and usually without regard to being the lowest noise devices, so some of their unrectified AC gets back on the ground system, or simply hums through the amp. It's best to just figure out a way to condition the DC power to the pedals if possible, since the pedals themselves rarely have enough decoupling built into them to be totally hum free. In a guitar amp, the ground should be going to the chassis. The neutral and hot should go to the power transformer. After rectification, the 0V side of the rectifiers is referenced to the earth/chassis ground. IF there is a proper amount of decoupling for the circuit, then there should be no significant AC noise on the earth/chassis ground. IF you were to lift ground on a 3 wire guitar amp (which shouldn't be able to happen), then the "ground" can float upwards as the line voltage fluctuates, and you can get shocked as Tony was saying. I was probably using "balanced" in the wrong context. I was talking about a three prong AC plug. Thanks for the great info svart and tonycamphd. Learned some very valuable info and cleared up some major misconceptions from this article. OK, I see. there is NO balanced or differential AC power. In the USA, standard "line" power is a single powered conductor (the "hot") a current returning conductor (the "neutral") and a safety ground (the "ground"). Also in the USA, the neutral and ground are tied together at the circuit breaker box. They are both "grounded" by either attaching them to metallic water pipes that are fed from a metallic main pipe, or by a ground rod inserted into the earth next to the house. They are also attached to the "ground" guy-wire that goes from the house to the utility pole/transformer. However, due to the resistance/impedance of the power cable, some parts of the house/building can have a slightly higher current on the neutral/ground. Plugging something in on that end of the system, like an amplifier, and then plugging something in at the other end of the system, like a pedalboard, can cause current to flow through the shields of the cables stretched between. This would cause extra hum on the system. In the studio it's best to simply power all things on the same outlets if possible, and definitely on the same circuit.
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Post by KJ on Jul 16, 2014 2:17:29 GMT -6
Scary
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Post by svart on Jul 16, 2014 8:01:48 GMT -6
Scary Yes, you have no idea. That's probably a couple KV on those lines. He is most likely died, as you can see toward the end a little flame out on the head/hair and some liquid running down the side of the train.. If the power had been higher (yes higher) he might have actually lived because it would have instantly fried his hand/fingers off before burning out his nervous system. But yeah, I was working on the house one night and the power flickered and I heard a loud ZZZZZZTTT sound (electric arc) and a POP. I went outside to see what was going on and a bunch of people down the street had gathered around something in the road. i grabbed a flashlight and walked down there. Before I got down there I could smell burnt hair and flesh (like bacon..) and saw a huge owl laying on the ground, with his wings and legs outstretched. All of his feathers had melted and fused together into something like a turtle shell. From the top of his head down his back was a huge cavity where the current had flowed (probably through the spinal cord). Obviously he had landed on a wire and bridged another one causing a short through his body. At least death was instantaneous.
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Post by svart on Jul 16, 2014 8:05:22 GMT -6
Another interesting one was myself playing guitar one night during a thunderstorm. lightning hit right outside the house on the side where the grounding rod was located. As soon as I heard the crack I was shocked through the guitar.
The power from the lightning came up through the grounding rod and ground wires, through the guitar cable and into my hands.
My hands tingled for a couple hours that night.
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Post by Bob Olhsson on Jul 16, 2014 15:58:46 GMT -6
Unfortunately most computer and audio gear power supply designers are utterly incompetent and that includes Apple. If you want your ear bent for a week, just ask some touring sound folks about this unfortunate fact of audio life.
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