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Moved to a new house and amps are buzzing like crazy; power lines?
Old 14th December 2020 | Show parent
  #61
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nosebleedaudio's Avatar
 
🎧 15 years
Quote:
Originally Posted by _starbelly View Post
Here is the contact point between the ground wire and ground rod. Given my lack of expertise, I can't say if this looks normal or not.
Simply looks like its been in the ground for a while.
If the connector is tight then fine, I would be more concerned about the outlets wired correctly & IF they have a ground wire..
But adding a 2nd ground rod would be a good thing, I would make it copper plated..

Last edited by nosebleedaudio; 14th December 2020 at 10:21 AM..
Old 14th December 2020 | Show parent
  #62
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c1010's Avatar
 
Quote:
Originally Posted by nosebleedaudio View Post
Simply looks like its been in the ground for a while.
If the connector is tight then fine, I would be more concerned about the outlets wired correctly & IF they have a ground wire..
But adding a 2nd ground rod would be a good thing, I would make it copper plated..
Totally agree wrt the outlets and the feeds from the main panel. If they're still 2-wire, as we were talking about way back when, then that's got to be addressed in parallel with the concern about a possibly high-resistance path to earth (corroded wire or dodgy clamp or corroded rod).

If the remediation is forecast to be ridiculously expensive -- pulling new 3-wire through the walls, for instance -- then John Eppstein's suggestion of a shielded run from the panel to your practice room makes a lot of sense. You could even run 3-wire Romex inside galvanized & grounded conduit, and run the conduit outside the house and clamp it against the siding. Drill 2 holes and it's done. Big labor saver.

Side note on the choice between galvanized rods and copper ones: I wouldn't use a copper rod near buried steel, especially steel that's load-bearing. The steel might get (chemically) eaten away. That's probably n/a to you, but you should check anyway. Otherwise I totally agree with Nosebleed's call on their relative lifespans.

Can't wait to hear what the electrician finds.
Old 14th December 2020 | Show parent
  #63
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nosebleedaudio's Avatar
 
🎧 15 years
If it was me and I did get a 2nd rod installed I would abandon the galvanized rod and have two new copper plated rods driven...
There are MANY romex runs that have NO problems..
Old 14th December 2020 | Show parent
  #64
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c1010's Avatar
 
Quote:
Originally Posted by nosebleedaudio View Post
If it was me and I did get a 2nd rod installed I would abandon the galvanized rod and have two new copper plated rods driven...
There are MANY romex runs that have NO problems..
Agreed. But there are many that do. So, let's not assume a problem scenario that may or may not exist. At this point we don't have nearly enough data to identify root causes, let alone decide on a suitable remediation.
Old 14th December 2020
  #65
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hswin's Avatar
 
🎧 10 years
You can check the ground rod by moving your small radio close to the ground wire and all the way back to the panel. If there is any noise at the ground rod, have the electrician check, repair it (if possible) or replace. Of course there is also the meter method. Use a standard multi-meter and stick a screwdriver nearby directly into the ground with one meter lead, and poke into the ground wire with the other lead or directly to the service panel screw. It should read real close to zero ohms and zero voltage ac. Any reading higher than that may be a culprit. Good grounding is always necessary in the recording room.
Old 14th December 2020 | Show parent
  #66
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Rick Dalton's Avatar
Quote:
Originally Posted by _starbelly View Post
To my untrained eye, it does indeed look nasty, haha.

I know the panel is new, but perhaps they used the old ground rod.
You mention about picking up more EMI, when close to the meter, you might ask your electrician that coming, about smart meter emissions. That rod's easy to get out..., The hard part (if its an 8 or 9 footer) is getting it back in.
Old 14th December 2020
  #67
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RBBlackstone's Avatar
 
🎧 10 years
Electrician checkup - good idea

It is a great idea to have an electrician check your ground rod and panel bonding. Neutral and earth ground should only come together once at the service entrance. People let ground and neutral touch. A handyman installs something and ties too many neutrals together at some point. Rust never sleeps. Good time for a checkup.

It's good to become educated yourself a bit before you bringing in the electrician. A good electrician will have goals involving meeting code (good), but may not really have much understanding of different noise sources. Phillip Giddings wrote Audio System Design and installation. I studied every page and it is highly recommended. This link covers some info from Giddings book.

https://www.jhbrandt.net/wp-content/...ementation.pdf

Note the section 4.2 on the ground conductor to the panel for low noise. They refer to a resistance for high EMI and high dynamic range that is .001 to .0001 ohms. That is huge copper and an electrician will think in terms of meeting the current carrying capacity and not impedance to ground. You also don't want coils or sharp turns in that cable either. That increases inductance. I have put #00 welding cable in for some studios to meet that spec and it's the size of your thumb. It's right, but it looks wrong to an electrician and from their point of view overkill and unneeded expense.

Excerpted jpg here:
http://RBBlackstone.com/files/RB/Phi...ingsGround.jpg

Phillip Giddings, Neil Muncy, Bill Whitlock, Dean Jensen and others have lots of great info and research. Look into the Pin 1 problem and RFI verses magnetic interference. That and interconnection for common gear is a giant rabbit hole. lol
Old 14th December 2020 | Show parent
  #68
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TeleBluesDude's Avatar
 
Quote:
Originally Posted by _starbelly View Post
@ John Eppstein Hot damn. I’m a first time homeowner been here for less than two weeks, I’m not sure I can just move out, haha.

I will generate some questions based on your comment and bring it to the attention of the electrician I know.

Unless I am mistaken, it seems as though your comment implies that the problem is internal/part of the house itself; could it be the case that the house is fine and this is all due to interference from the high voltage power lines?
This may make sense...or maybe not.

Years ago playing is bars there would often be buzzing issues on stage, so it was necessary to have a dedicated line wired to the stage. If it’s properly grounded, all should be good.
Old 14th December 2020 | Show parent
  #69
Questions for clarification:

Given that the noise I experience goes away when I turn the guitar volume down, it suggests that the noise is being picked up from the air, and not due to something like a ground loop.

How does addressing an issue like a faulty ground rod address the fact that the noise is being picked up from the air? Would there be excess noise in my electrical wiring due to a faulty ground that could be picked up through the air by my guitar?

I have heard people mention having dedicated circuits for the room I play in (which also contains the breaker panel). How could a dedicated circuit help in this case?

Last edited by _starbelly; 14th December 2020 at 06:25 PM.. Reason: Additional details/questions
Old 14th December 2020 | Show parent
  #70
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John Siau's Avatar
 
🎧 15 years
Quote:
Originally Posted by _starbelly View Post
I got my handheld AM/FM radio in! For my first round of testing, I found two frequencies that were basically unused (towards the top and bottom of the AM range) and walked around the house. Here are some initial observations (some of these may be obvious to people with more knowledge on this topic).
  • In the room with my gear, the lower frequency produces a sound similar to the standard amp buzz, whereas the higher frequency produced a more sustained "note-like" sound that only seemed to appear in that room.
  • Getting close to the breaker box greatly increased the noise coming from the radio, and cutting off the breaker for the room my gear is in made no change in the level of noise.
  • In some cases, the orientation of my body holding the radio affected how prevalent the noise was.
  • Running the radio directly in front of LED light fixtures in the ceiling produced noise, even when they are off.
  • Surprisingly going outside, in view of the high voltage power lines, did not seem to increase noise. It actually seemed quieter outside.
  • No such noise was present in the FM frequencies.

This weekend I will be more systematic about exploring around the house with the radio, and will even go closer to the power lines. One of the next steps will be to turn the main breaker off to see if this makes a change in the noise the radio picks up.

Any feedback you may have to improve how I may go about this using the radio would be appreciated!
There are three distinct types of interference from AC power (conducted, magnetic, and electrostatic) with three very distinct solutions. You must determine which type of interference you are experiencing or you will spend lots of time and money on the wrong solution. You have one chance in three at guessing correctly. I suspect that you are experiencing magnetic interference and possibly some electrostatic interference but not conducted interference. If a battery powered guitar amp and guitar produces AC hum, this is almost certainly caused by magnetic interference, especially if the hum changes dramatically as the guitar is rotated and tilted. The battery operation rules out conducted interference problems.

Grounding, balanced interfaces, and isolation transformers can solve conducted interference problems, but these are completely ineffective at solving the other two types of interference. If you experience interference while audio devices are completely disconnected from the AC power and AC grounds (battery-powered guitar amp test), you do not have a conducted interference problem.

Electrostatic shielding, Faraday cages, twisted pairs, shielded cables and so forth, are effective at shielding against electrostatic (capacitively coupled) interference but are completely ineffective at shielding against magnetic fields. These shields also will not solve conducted interference problems. You could spend a lot of money on shielding and accomplish nothing if you are experiencing magnetic interference.

I suspect you have a magnetic interference problem and this is the worst possible diagnosis. If this magnetic interference is coming from the power lines, sell the house or live with whatever immunity you can achieve with a humbucker pickup. Years ago, a studio was constructed in NY city directly above a buried sub station. Magnetic interference from the sub station transformers made the studio completely unusable and completely unsalvageable. Magnetic shielding is very expensive and often not very effective. Star-quad XLR cables can provide immunity to magnetic interference for individual cable runs, but the audio devices themselves may pick up the magnetic interference. In the case of the studio, the traces on the console circuit boards picked up the magnetic interference, creating hum on all channel strips and on the mix busses.

Conducted Interference:

The first type of interference is conducted interference. If current is being carried through any of the ground conductors, voltage differences will occur across your ground system, and you will have a "ground loop". If this is the case, you may be able to measure AC voltage differences between various ground points in the system (one side of the house to the other, one room to the next, one outlet to the next, or one chassis to the next). Balanced XLR interfaces provide excellent immunity to AC currents in the ground system. To work properly, pin 1 of the XLR must be bonded to the chassis and not to a ground point on a circuit board. Isolation transformers and XLR ground lift switches can be used when a product does not have pin 1 bonded directly to the chassis. Isolation transformers can also be used to solve ground loop problems in unbalanced connections. A clamp-on ammeter can be used to measure currents in the grounding system for your AC wiring. If high currents are measured near your main grounding rod while all circuits in the house are off, the power poles on the street are inadequately grounded. If so, you may have a few volts AC voltage difference between your AC outlets grounds and your water pipes, cable antenna grounds, and other ground connections. I would check for current in the main ground rod cable to make sure that this is reasonably low. Please note that this discussion is focused on AC hum. Radio frequency interference can also be conducted through the AC power distribution system and it can enter poorly filtered audio devices, but this would not cause AC hum. AC line filters and ferrite beads can attenuate conducted RF interference, but your are reporting AC hum, so these filters would offer no improvement.

Electrostatic Interference (capacitive interference):

If you are hearing interference from radio stations, power tools, and household appliances, even when running on battery power, then you have an electrostatic interference problem. Improve your cable shielding and add shielding to the studio walls if necessary. Before adding shielding, make sure that the RF interference is not conducted. But, since your primary complaint is AC hum you are probably not experiencing electrostatic interference. However, if the AC line interference is comprised primarily of high-frequency harmonics of the line frequency, you may be receiving electrostatic interference from corona discharge from the high-voltage lines.

Magnetic Interference

Every conductor that is carrying current emits a magnetic field. Any conductor that passed through this magnetic field will have a voltage induced by the magnetic field. The emitting and receiving wires act like the primary and secondary windings in a transformer. Power is transmitted magnetically and cannot be attenuated by copper or aluminum shields. Steel and iron can provide some shielding but these materials can actually increase the magnetic conduction if improperly applied. Expensive mumetal shielding can provide some immunity. Audio transformers, microphones and guitar pickups often employ small mumetal shields to provide increased immunity to magnetic fields. This material is very expensive and it is not practical to shield an entire room, and probably not even a single chassis.

Diagnostic tools:

EMF meter. Most phones have built-in three-axis EMF sensors. Download one of the many EMF meter applications from the android or iPhone app store.

Magnetic pickup coil. Purchase a telephone pickup coil (less than $10) and connect it to a battery-powered audio amplifier. Search for "telephone magnetic pickup coil". You will find several on Amazon. Walk around your house and yard to determine the source of the magnetic interference. Rotate the coil to determine direction. Your guitar pickup can be used in place of the telephone pickup coil, but the small coil is much more convenient.

AC Voltmeter. Measure the voltage between various ground points if you suspect conducted (ground loop) problems.

Clamp-on AC ammeter. Check for current in your AC ground conductors and AC ground rod cables to verify that you do not have stray currents in your ground system (if you suspect conducted ground loop problems).

Don't go looking for ground loop problems if you experience the same interference while running on battery power. Use the last two tools (AC voltmeter and ammeter) if the interference goes away when operating on battery power.

Last edited by John Siau; 14th December 2020 at 09:46 PM.. Reason: Correction: EMF sensor applications are also available for iPhone
Old 14th December 2020 | Show parent
  #71
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Rick Dalton's Avatar
Quote:
Originally Posted by _starbelly View Post
Questions for clarification:

Given that the noise I experience goes away when I turn the guitar volume down, it suggests that the noise is being picked up from the air, and not due to something like a ground loop.

How does addressing an issue like a faulty ground rod address the fact that the noise is being picked up from the air? Would there be excess noise in my electrical wiring due to a faulty ground that could be picked up through the air by my guitar?

I have heard people mention having dedicated circuits for the room I play in (which also contains the breaker panel). How could a dedicated circuit help in this case?
What guitar and amp?
Old 14th December 2020 | Show parent
  #72
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Rick Dalton's Avatar
Quote:
Originally Posted by John Siau View Post
There are three distinct types of interference from AC power (conducted, magnetic, and electrostatic) with three very distinct solutions. You must determine which type of interference you are experiencing or you will spend lots of time and money on the wrong solution. You have one chance in three at guessing correctly. I suspect that you are experiencing magnetic interference and possibly some electrostatic interference but not conducted interference. If a battery powered guitar amp and guitar produces AC hum, this is almost certainly caused by magnetic interference, especially if the hum changes dramatically as the guitar is rotated and tilted. The battery operation rules out conducted interference problems.

Grounding, balanced interfaces, and isolation transformers can solve conducted interference problems, but these are completely ineffective at solving the other two types of interference. If you experience interference while audio devices are completely disconnected from the AC power and AC grounds (battery-powered guitar amp test), you do not have a conducted interference problem.

Electrostatic shielding, Faraday cages, twisted pairs, shielded cables and so forth, are effective at shielding against electrostatic (capacitively coupled) interference but are completely ineffective at shielding against magnetic fields. These shields also will not solve conducted interference problems. You could spend a lot of money on shielding and accomplish nothing if you are experiencing magnetic interference.

I suspect you have a magnetic interference problem and this is the worst possible diagnosis. If this magnetic interference is coming from the power lines, sell the house or live with whatever immunity you can achieve with a humbucker pickup. Years ago, a studio was constructed in NY city directly above a buried sub station. Magnetic interference from the sub station transformers made the studio completely unusable and completely unsalvageable. Magnetic shielding is very expensive and often not very effective. Star-quad XLR cables can provide immunity to magnetic interference for individual cable runs, but the audio devices themselves may pick up the magnetic interference. In the case of the studio, the traces on the console circuit boards picked up the magnetic interference, creating hum on all channel strips and on the mix busses.

Conducted Interference:

The first type of interference is conducted interference. If current is being carried through any of the ground conductors, voltage differences will occur across your ground system, and you will have a "ground loop". If this is the case, you may be able to measure AC voltage differences between various ground points in the system (one side of the house to the other, one room to the next, one outlet to the next, or one chassis to the next). Balanced XLR interfaces provide excellent immunity to AC currents in the ground system. To work properly, pin 1 of the XLR must be bonded to the chassis and not to a ground point on a circuit board. Isolation transformers and XLR ground lift switches can be used when a product does not have pin 1 bonded directly to the chassis. Isolation transformers can also be used to solve ground loop problems in unbalanced connections. A clamp-on ammeter can be used to measure currents in the grounding system for your AC wiring. If high currents are measured near your main grounding rod while all circuits in the house are off, the power poles on the street are inadequately grounded. If so, you may have a few volts AC voltage difference between your AC outlets grounds and your water pipes, cable antenna grounds, and other ground connections. I would check for current in the main ground rod cable to make sure that this is reasonably low. Please note that this discussion is focused on AC hum. Radio frequency interference can also be conducted through the AC power distribution system and it can enter poorly filtered audio devices, but this would not cause AC hum. AC line filters and ferrite beads can attenuate conducted RF interference, but your are reporting AC hum, so these filters would offer no improvement.

Electrostatic Interference (capacitive interference):

If you are hearing interference from radio stations, power tools, and household appliances, even when running on battery power, then you have an electrostatic interference problem. Improve your cable shielding and add shielding to the studio walls if necessary. Before adding shielding, make sure that the RF interference is not conducted. But, since your primary complaint is AC hum you are probably not experiencing electrostatic interference. However, if the AC line interference is comprised primarily of high-frequency harmonics of the line frequency, you may be receiving electrostatic interference from corona discharge from the high-voltage lines.

Magnetic Interference

Every conductor that is carrying current emits a magnetic field. Any conductor that passed through this magnetic field will have a voltage induced by the magnetic field. The emitting and receiving wires act like the primary and secondary windings in a transformer. Power is transmitted magnetically and cannot be attenuated by copper or aluminum shields. Steel and iron can provide some shielding but these materials can actually increase the magnetic conduction if improperly applied. Expensive mumetal shielding can provide some immunity. Audio transformers, microphones and guitar pickups often employ small mumetal shields to provide increased immunity to magnetic fields. This material is very expensive and it is not practical to shield an entire room, and probably not even a single chassis.

Diagnostic tools:

EMF meter. If you have an android phone, it has a built-in three-axis EMF sensor. Download one of the many EMF meter applications from the android store. If you have an iPhone, you are out of luck. This is the one feature I miss after switching to an iPhone.

Magnetic pickup coil. Purchase a telephone pickup coil (less than $10) and connect it to a battery-powered audio amplifier. Search for "telephone magnetic pickup coil". You will find several on Amazon. Walk around your house and yard to determine the source of the magnetic interference. Rotate the coil to determine direction. Your guitar pickup can be used in place of the telephone pickup coil, but the small coil is much more convenient.

AC Voltmeter. Measure the voltage between various ground points if you suspect conducted (ground loop) problems.

Clamp-on AC ammeter. Check for current in your AC ground conductors and AC ground rod cables to verify that you do not have stray currents in your ground system (if you suspect conducted ground loop problems).

Don't go looking for ground loop problems if you experience the same interference while running on battery power. Use the last two tools (AC voltmeter and ammeter) if the interference goes away when operating on battery power.
This is why I said it was an bad idea to merge this thread with another "on going thread" same issue. Anyone have a clue, how many slutz have threads asking about guitar buzz/hum...on here? And the buzz goes away if the guitar is turned down or the strings are touched.
Old 14th December 2020 | Show parent
  #73
Quote:
Originally Posted by Rick Dalton View Post
What guitar and amp?
I’m using a variety of guitars with single coils and humbuckers with a variety of Mesa amps.
Old 14th December 2020 | Show parent
  #74
Additionally, to the people who are literally suggesting I sell the house or move, I’m not sure you’re realizing how incredibly unhelpful and unrealistic that “advice” is for a first time homeowner who has been in this home for a little over 2 weeks.
Old 14th December 2020 | Show parent
  #75
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Rick Dalton's Avatar
Quote:
Originally Posted by _starbelly View Post
I’m using a variety of guitars with single coils and humbuckers with a variety of Mesa amps.
Can you hear a difference if you left the guitar cord up off the floor? Reason I ask is, electricity is always looking for ground and this is a symptom if the hum gets worse if the cord is on or closer to the floor. Do the humbuckers make any difference?
Old 14th December 2020 | Show parent
  #76
Maybe a little. The hum gets a tiny bit quieter if I lift the cable from the ground with no guitar plugged in. It gets maximally loud when I plug a guitar in. Humbuckers help, but do not completely eliminate the issue. My main curiosity is understanding what is causing that harmonic hum that I am hearing (I have posted examples previously in the thread, and encourage you to check them out if you haven’t done so already).
Old 14th December 2020 | Show parent
  #77
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John Siau's Avatar
 
🎧 15 years
Not suggesting a move unless you plan to build a studio and you confirm that you have magnetic interference from the power lines and/or nearby transformers.

Magnetic guitar pickups are designed to pick up the magnetic fields produced by moving strings. Unfortunately, they are also very effective at picking up stray magnetic fields.

Magnetic fields need to be carefully controlled in any studio that will be used to record an electric guitar.
Old 14th December 2020 | Show parent
  #78
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John Siau's Avatar
 
🎧 15 years
Here is a great article that explains some of the causes of magnetic interference and some of the methods used to mitigate the interference:

http://www.emfservices.com/magnetic.htm
Old 15th December 2020
  #79
Gear Nut
A friend of mine called and asked me to come over to his home studio, which is in an outdoor building, separate from the house. He was having an issue that sounds very similar. No matter what he did, he could not record anything without having an annoying buzz on the track. The home was WWII era. There was a GA 1073 clone, a class A design. Every time U turned this preamp on, the power conditioner would shut everything down.

In the end, the electrical panel had to be replaced. Everything's sounding fine now.
Old 15th December 2020 | Show parent
  #80
Quote:
Originally Posted by LLSentelle View Post
A friend of mine called and asked me to come over to his home studio, which is in an outdoor building, separate from the house. He was having an issue that sounds very similar. No matter what he did, he could not record anything without having an annoying buzz on the track. The home was WWII era. There was a GA 1073 clone, a class A design. Every time U turned this preamp on, the power conditioner would shut everything down.

In the end, the electrical panel had to be replaced. Everything's sounding fine now.
What about the electrical panel merited replacement?
Old 15th December 2020 | Show parent
  #81
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nosebleedaudio's Avatar
 
🎧 15 years
Quote:
Originally Posted by _starbelly View Post
What about the electrical panel merited replacement?
Maybe it didn't have the added Ground bus the later panels had..
Old 15th December 2020 | Show parent
  #82
Gear Head
 
Hi. Not sure if I missed some of this, but here goes. I'll ignore magnetic coupling, and anything that needs a Faraday cage and focus mainly on easy "fixes" and conducted noise. Granted, the OP has said that he gets hum from an amp with a cable attached (no guitar). I didn't see that he had tried the battery powered amp suggestion (that was a good one). You want to do such experiments with the system (guitar, cable, amp) in normal operation. Stuff like, "when I touch the tip and ring, the noise changes" means nothing. You are simply adding your very own antenna and impedance to the circuit. Turning the volume down, likewise.

- Have you tried better guitar cable, like Mogami, particularly with a battery amp? The shield effectiveness is a good question here, though at 60 and 120Hz. you likely won't get too far with that one. You might be able to attenuate the higher pitched noise.

- The OP might want to try something like Tripplite's Isobar EMI filter power strips (in a metal case) between the amp and the wall plug if the battery amp helps. They offer a fair amount of filtering without being "high-end audio gear" - they're not very expensive. Check to see whether that helps with the hum. If it does, you probably have more conducted stuff (the grounding will be needed, though).

- I don't think the OP mentioned what part of the country he's in. This is potentially significant if there's little conductivity in the dirt. In some rocky, arid regions, the ground is made as a ring around the house, not very deep - instant ground loop. I doubt that this is the case here due to the picture of a driven ground rod.

- The ground in a 1950's house may not have existed when new, as has been suggested by the 2-wire circuit comments. That suggests the new panel got a new ground - the green wire shown in a pic isn't from the '50s, nor is the ground rod itself. I did my main ground as 3 rods driven at 10 ft. intervals, a single ground wire through each, and back to the panel as quick as I could. All that is buried in concrete under my entryway to keep it moist. Run some (salted?) water around the ground rod at your house, to see if that makes any difference.

- If there was a ground when the house was built, it was likely connected to the water pipe. That connection is likely shot by now. If you can find it, replace the connector, and clean the wire. When the panel is open, check that all main ground connections are adjacent in the panel connector to reduce resistance between them. They would be best right up near where the neutral wire attaches.

- The ground wiring should be #4 copper in all cases for a 200 amp panel. That's what the NEC says doesn't need added protection from damage, so most electricians play it that way. Current code calls for 3 ground connections in my neck of the woods. The connections should be a star configuration, meaning each ground returns to the panel and the various wires are connected to the buss as close together as possible.

- A house built in the 1950's shouldn't have aluminum wiring, unless someone added something later. Aluminum was a short-lived "thing" in the '70s. That said, some of the connections for wiring in that vintage could easily have loosened up over time. This would be another advantage to a new, dedicated circuit.

- The brand and age of the panel is significant. When I replaced my service entrance panel in 2006, I bought a Siemens panel, because the power busses were solid copper, no tin coating. Some Square D panels screw the breaker onto the busses. Those get loose over time and create some havoc.

- The suggestion of a dedicated breaker and line to one or two outlets in your playing room is very good. You can eliminate the chance of bad connections, wires going to more rooms than you expected, ground loops elsewhere in the circuit, as well as knowing what you have. Also, it should be a short run to minimize the antenna length. If the "new panel" is surface mounted, you could easily run the new circuit in conduit with metal box(es) to reduce noise (EMI) to THAT CIRCUIT.

- When the panel is open, have the electrician wiggle the breakers in and out if the panel uses stab lock breakers. That will clear any oxidation on the buss connections.

- Did anyone have the OP check to see whether the local distribution system has a lot of lines running parallel to the high tension stuff on the way to the house? If you have a few miles of wires going down a parallel path with the transmission lines, they'll couple energy there that's going to make a mess.

- If the stepdown transformer to the house isn't close to the entrance, you'll pick up some from that distance. Might want to jiggle the meter and check the meter base connections, too while you're at it.

That's all for now. Try the easy/cheap stuff, then work your way out from there. Best of luck.
Old 15th December 2020
  #83
Gear Addict
 
To start, let me say that I worked in the EMI-RFI suppression field for a number of years and have a lot of experience helping clients solve these types of noise issues. That said, I am thinking that filtering in the classic sense (removing high frequency noise) isn't going to help. Most problems with high frequency noise in audio are caused by what is called audio-rectification, where the high frequency energy creates noise unrelated to the frequency of the original noise.

I ran your clip into a spectrum analyzer, and have pronounced peaks in mostly the 60 hz region, and a peak at around 550 hz, which is the "overtone" you are talking about. If I were to guess, I am thinking you are getting this noise from the power lines in proximity to your house. The 550 hz noise is odd. Do you have any industrial buildings nearby? There may be back EMF on your lines from some large equipment into the power grid.

As others have pointed out, grounding issues are usually the cause of your 60 hz noise. You already mentioned using an electrician to check out your wiring.

If this was my situation, here are some quick and easy checks you can make.

1. Get a long extension cord and connect to an outlet adjacent to your panel, run to your room you use for music. Does this help?
2. Using same cord, repeat test outdoors on the side of house your room is located.
3. Using longer cord, ask your neighbor(s) to plug cord in and repeat above.

This will quickly rule out your house wiring and give you some indication of the source of the noise. If you still get the same excessive 60 and 550 hz noise even plugged into the neighbors house, well you have a bigger issue at hand.
Old 15th December 2020 | Show parent
  #84
Quote:
Originally Posted by SynthFan65 View Post
Hi. Not sure if I missed some of this, but here goes. I'll ignore magnetic coupling, and anything that needs a Faraday cage and focus mainly on easy "fixes" and conducted noise. Granted, the OP has said that he gets hum from an amp with a cable attached (no guitar). I didn't see that he had tried the battery powered amp suggestion (that was a good one). You want to do such experiments with the system (guitar, cable, amp) in normal operation. Stuff like, "when I touch the tip and ring, the noise changes" means nothing. You are simply adding your very own antenna and impedance to the circuit. Turning the volume down, likewise.

- Have you tried better guitar cable, like Mogami, particularly with a battery amp? The shield effectiveness is a good question here, though at 60 and 120Hz. you likely won't get too far with that one. You might be able to attenuate the higher pitched noise.

- The OP might want to try something like Tripplite's Isobar EMI filter power strips (in a metal case) between the amp and the wall plug if the battery amp helps. They offer a fair amount of filtering without being "high-end audio gear" - they're not very expensive. Check to see whether that helps with the hum. If it does, you probably have more conducted stuff (the grounding will be needed, though).

- I don't think the OP mentioned what part of the country he's in. This is potentially significant if there's little conductivity in the dirt. In some rocky, arid regions, the ground is made as a ring around the house, not very deep - instant ground loop. I doubt that this is the case here due to the picture of a driven ground rod.

- The ground in a 1950's house may not have existed when new, as has been suggested by the 2-wire circuit comments. That suggests the new panel got a new ground - the green wire shown in a pic isn't from the '50s, nor is the ground rod itself. I did my main ground as 3 rods driven at 10 ft. intervals, a single ground wire through each, and back to the panel as quick as I could. All that is buried in concrete under my entryway to keep it moist. Run some (salted?) water around the ground rod at your house, to see if that makes any difference.

- If there was a ground when the house was built, it was likely connected to the water pipe. That connection is likely shot by now. If you can find it, replace the connector, and clean the wire. When the panel is open, check that all main ground connections are adjacent in the panel connector to reduce resistance between them. They would be best right up near where the neutral wire attaches.

- The ground wiring should be #4 copper in all cases for a 200 amp panel. That's what the NEC says doesn't need added protection from damage, so most electricians play it that way. Current code calls for 3 ground connections in my neck of the woods. The connections should be a star configuration, meaning each ground returns to the panel and the various wires are connected to the buss as close together as possible.

- A house built in the 1950's shouldn't have aluminum wiring, unless someone added something later. Aluminum was a short-lived "thing" in the '70s. That said, some of the connections for wiring in that vintage could easily have loosened up over time. This would be another advantage to a new, dedicated circuit.

- The brand and age of the panel is significant. When I replaced my service entrance panel in 2006, I bought a Siemens panel, because the power busses were solid copper, no tin coating. Some Square D panels screw the breaker onto the busses. Those get loose over time and create some havoc.

- The suggestion of a dedicated breaker and line to one or two outlets in your playing room is very good. You can eliminate the chance of bad connections, wires going to more rooms than you expected, ground loops elsewhere in the circuit, as well as knowing what you have. Also, it should be a short run to minimize the antenna length. If the "new panel" is surface mounted, you could easily run the new circuit in conduit with metal box(es) to reduce noise (EMI) to THAT CIRCUIT.

- When the panel is open, have the electrician wiggle the breakers in and out if the panel uses stab lock breakers. That will clear any oxidation on the buss connections.

- Did anyone have the OP check to see whether the local distribution system has a lot of lines running parallel to the high tension stuff on the way to the house? If you have a few miles of wires going down a parallel path with the transmission lines, they'll couple energy there that's going to make a mess.

- If the stepdown transformer to the house isn't close to the entrance, you'll pick up some from that distance. Might want to jiggle the meter and check the meter base connections, too while you're at it.

That's all for now. Try the easy/cheap stuff, then work your way out from there. Best of luck.
Thanks so much for your response! Let me address some questions:

-I would like to try some nicer cables; perhaps I can get one and try it out soon. I have also not tried the battery powered amp idea yet;I just ordered a Blackstar FLY3 that will be here next week.

-I am in Seattle, which isn't rocky or arid.

-I don't know the specific age of the panel, but it is a newer Siemens panel.

I will have to go back and compile a list of questions based on all the feedback here for my electrician.
Old 15th December 2020 | Show parent
  #85
Quote:
Originally Posted by Jeffw5555 View Post
To start, let me say that I worked in the EMI-RFI suppression field for a number of years and have a lot of experience helping clients solve these types of noise issues. That said, I am thinking that filtering in the classic sense (removing high frequency noise) isn't going to help. Most problems with high frequency noise in audio are caused by what is called auto-rectification, where the high frequency energy creates noise unrelated to the frequency of the original noise.

I ran your clip into a spectrum analyzer, and have pronounced peaks in mostly the 60 hz region, and a peak at around 550 hz, which is the "overtone" you are talking about. If I were to guess, I am thinking you are getting this noise from the power lines in proximity to your house. The 550 hz noise is odd. Do you have any industrial buildings nearby? There may be back EMF on your lines from some large equipment into the power grid.

As others have pointed out, grounding issues are usually the cause of your 60 hz noise. You already mentioned using an electrician to check out your wiring.

If this was my situation, here are some quick and easy checks you can make.

1. Get a long extension cord and connect to an outlet adjacent to your panel, run to your room you use for music. Does this help?
2. Using same cord, repeat test outdoors on the side of house your room is located.
3. Using longer cord, ask your neighbor(s) to plug cord in and repeat above.

This will quickly rule out your house wiring and give you some indication of the source of the noise. If you still get the same excessive 60 and 550 hz noise even plugged into the neighbors house, well you have a bigger issue at hand.
Very interesting, regarding audio-rectification.

So the 550Hz tone is the overtone? What's interesting is that with the AM radio, I get a note like overtone in the house, but not really by the power lines. By the powelines I get more static, but this doesn't happen until well into my backyard; the room I play in does not extend this far out. I don't believe there are any industrial buildings in the immediate vicinity.

For clarification, the outlet is in the room I would use for music. There is a spare room I could potentially move to, but I've tested my amps in basically every room; the noise is always present.

Nonetheless, I will get an extension cord.
Old 15th December 2020 | Show parent
  #86
Gear Head
 
Quote:
Originally Posted by _starbelly View Post
What's interesting is that with the AM radio, I get a note like overtone in the house
Do you get the overtone with power on/off in your house? I get tones on the AM radio from certain appliances (TV is a big one) and some LED lamps I built, but if I kill the power they go away. And also a crazy tone by the power meter outside.
Old 15th December 2020 | Show parent
  #87
Quote:
Originally Posted by quarantinebeats View Post
Do you get the overtone with power on/off in your house? I get tones on the AM radio from certain appliances (TV is a big one) and some LED lamps I built, but if I kill the power they go away. And also a crazy tone by the power meter outside.
I have yet to try by turning off the main power in the house. I will try today after work. I believe I got a lot of noise by the power meter outside as well.
Old 15th December 2020 | Show parent
  #88
Lives for gear
 
🎧 5 years
TL:DR

Had an 1830's house with bad wiring.. I assume that

1) you have checked all outlets with a circuit tested to verify they are grounded?.. if it is old house with two fabric conductors and a "grounded" conduit you may be able to fix some/all of them as the issue is 99% either inside the socket outlet box or a junction box..if this is the case seriously just get the whole house rewired.. fabric covered wiring is a fire risk.

2) Before you sell up and move (JOKING!!!!) turn off/unplug all non incandescent lighting, LED bulbs and dimmer switches can cause problems. So can fridges, freezers etc.. make the whole house electrically dark as an experiment.

3) is the problem worse in late afternoon/evening vs (say) 10am?.. this would be then noise on your incoming lines from the neighborhood and could support a poor house ground theory (not that i buy into it if the connection is strong and the rod doesn't move.. for a suspicious ground, soaking the area would dramatically improve the ground contact and would be a controlled test)

I spent years mucking around trying to be cheap.. and while yes i moved (and its glorious) i really should have simply rewired the place a few months after moving in
Old 15th December 2020
  #89
Gear Head
 
Quote:
Originally Posted by Jeffw5555 View Post
To start, let me say that I worked in the EMI-RFI suppression field for a number of years and have a lot of experience helping clients solve these types of noise issues. That said, I am thinking that filtering in the classic sense (removing high frequency noise) isn't going to help. Most problems with high frequency noise in audio are caused by what is called audio-rectification, where the high frequency energy creates noise unrelated to the frequency of the original noise.

I ran your clip into a spectrum analyzer, and have pronounced peaks in mostly the 60 hz region, and a peak at around 550 hz, which is the "overtone" you are talking about. If I were to guess, I am thinking you are getting this noise from the power lines in proximity to your house. The 550 hz noise is odd. Do you have any industrial buildings nearby? There may be back EMF on your lines from some large equipment into the power grid.

As others have pointed out, grounding issues are usually the cause of your 60 hz noise. You already mentioned using an electrician to check out your wiring.

If this was my situation, here are some quick and easy checks you can make.

1. Get a long extension cord and connect to an outlet adjacent to your panel, run to your room you use for music. Does this help?
2. Using same cord, repeat test outdoors on the side of house your room is located.
3. Using longer cord, ask your neighbor(s) to plug cord in and repeat above.

This will quickly rule out your house wiring and give you some indication of the source of the noise. If you still get the same excessive 60 and 550 hz noise even plugged into the neighbors house, well you have a bigger issue at hand.
Good info Jeffw5555. Are you using an FFT device or an audio frequency SA? For the kind of work you mention, I'd expect a low-end frequency limit of something like 9kHz. on an SA. If you swept the audio range and only came up with 60 and 550Hz., that seems odd to me, too. You did mention peaks "around" 60Hz. and didn't mention amplitude. I don't suppose there's a way to post the spectrum?

I wouldn't offhand expect industrial equipment to produce a back EMF at 550Hz. Motor drives would be outside that range on both ends, I'd think.
Old 15th December 2020
  #90
Gear Guru
 
monkeyxx's Avatar
 
18 Reviews written
🎧 10 years
This thread is hot like a real live wire. Thanks to everyone who contributed, and especially the professionals who took the time to speak on this fascinating topic.
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