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I posted this in a different thread.

 

After doing a search of the forum, I yielded no topic labeled "grounding", so I thought I would start one. If you understand this topic or would like to understand this topic, or like me have consulted people who should understand this topic, chime away.

 

On the chance that hum is a symptom, perhaps the problem is not properly managing grounding and shielding on the home, stereo room and system in the first place.

 

These are my thoughts on the subject based on my reading, consulting from people who know what they are doing and realized experience.

 

I am neither an Electrician, EE nor Attorney, consult all three before frying yourself if you are in doubt.

 

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There is a long thread on a sub with a hum problem on the thread listed, which has a lots and lots and lots of posts on whether or not you can or can not get fried by 110VAC.

 

This is the link.

 

https://community.klipsch.com/index.php?/topic/154152-cheap-fix-on-ground-loop/

 

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A few thoughts:

 

A lot of the gear that we use is high current, and it can hurt or kill depending on the person and the circumstance.

 

If gear arrives with a 3 prong plug, use it.

 

A lot of Vintage gear does not have a third prong, it floats (hope I am using the term correctly)

 

Electricity wants to go to ground via the path of least resistance, which could be through (you or) another piece of gear if not wired properly.

 

Many homes the breaker box is wired (grounded) to a water pipe in the basement.

 

When I added 2 roof antennas, I followed the methodology of a commercial radio mast from a white paper after reviewing it with an (EE, EE, 30 year tech and lots of guys in the FM section of AK and an) electrician, by some freak occurrence it was the one who wired my house 25 years earlier. Both antennas tied together, then down 2 sides of the house to grounding rods, an additional 8 ft rod was driven into the ground next to the meter box. All three rods were tied together in a ring. Since my house has an aluminum skin, it too was on the same ground.

 

All of my gear including the sub are on the same 15A breaker, all of the gear is plugged into good quality power distribution units that provide RF filtering, high and low voltage protection. By plugging them all into the same distribution, they are all tied to the same ground the shortest path to earth.

 

All power cables must not be touching speaker or RCA cables etc as it could induce a signal under the right conditions.

 

Sometimes, it's worth the $200 to get an electrician in to verify the house wiring and the box and isolate a 15 amp circuit for the stereo gear. A trip to the Emergency Room $500.........a trip to the Morgue priceless.....

 

Better wall sockets than the crap the builders install are a few dollars each, if you are not sure read the directions and watch a few youtube videos and methodically replace every cheapo in the house, same goes for light switches. If you have a friend who knows what they are doing get them to help you do some until you are comfortable then buy them lunch somewhere.

 

On the RCA and other cables, shielded cables are dirt cheap, there is no excuse for not using them.

 

PCs can be very noisy, so if they are a problem connect to them via toslink aka optical isolation.

 

Things like lamps and the CFL bulbs can cause buzz and emit RF.

 

Spend the $60 for an RF and EMI meter and go around the house measuring everything in every mode, if cordless phones and cell phones don't give us brain tumors ........they should judging by their energy plumes.

 

Note: The electrician I mentioned earlier who had retired and was working at Home Depot, I purchased 4 whole house surge protectors from him that day for my home and buildings, kept asking about the grounding I installed.

 

I started to think I was missing a cue and had made a mistake, so I asked him straight up why we were going over it again.

 

Answer: This weekend I am going to upgrade the grounding on my home, and my brothers home and add roof antennas (and whole house surge devices). On his brother's house he was also going to ground the metal roof to the grounding rods (new install) on both sides of the house.

 

I have zero grounding issues (knock on wood) and my daughter asked me what I had done to the TV the day after we completed the grounding. I asked her why, "sharper picture, better colors, everything looks better".

 

Verify the house wire, tie the house to earth at multiple points, tie all earth grounds together via a ring, replace all the cheapo sockets and switches, plug all of the gear into the same power distribution box APC, Monster etc........ just get a good one, and use a dedicated 15Amp outlet if possible.

 

Upgrade the box with a whole house surge protector, $50 plus labor. It may save your Air Conditioner, furnace motor and all major appliances some day. The builders are too cheap to put them in unless forced to by code, even on million dollar new build houses.

Edited by Bubo
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Verify the house wire, tie the house to earth at multiple points, tie all earth grounds together via a ring, replace all the cheapo sockets and switches, plug all of the gear into the same power distribution box APC, Monster etc........ just get a good one, and use a dedicated 15Amp outlet if possible.

 

Having spent about 10 years studying ground loop hum -- Both problems and solutions, I had to get really serious last year when I started Bi-amping with Class 'D' Amps on my Khorn Bass Bins...... With that said Tracking down Ground Loop Hum is more 'Art than Science'. There are many causes and many solutions. Before I started Bi-amping my Solution was to float the ground on the plug with a cheater plug, but I added a GFCI on the Amp Circuits, which made it much safer than a 3 prong plug on a non GFCI circuit. This eliminated my hum with single amplifiers.

 

I had all of the 'Right Stuff' to prevent Ground Loop Hum and the experts I consulted (BTW - All of the Electricians and EE's, and Amp Builders that I hired were zero Help). I had a Separate Sub-Panel with Circuits totally dedicated to my Stereo System. Hospital Grade Outlets... The Best of Everything! And yet I had a 60 cycle hum when Bi-amping. Everything had 3 prong plugs (We never had this problem in the 60s and 70s when stereo gear had only two plugs and no path to ground to amplify.)

 

So, I spent about 3-4 weeks completely disassembling my Stereo System and hooking up 1 component at a time until I got the 'dreaded ground loop hum'.  I had a single dedicated circuit on a separate sub-panel with 12 gauge romex connecting three Hospital Grade outlets on that circuit about 4 feet apart from each other with nothing else on the circuit other than 2 monoblock amplifiers and a pre-amp. As soon as I plugged in an amplifier on another outlet on the same circuit, the ground loop hum would start.

 

The solution turned out to be a high quality extension cord from one Amplifier to the same outlet as the other Amplifier and Pre-amp. IOW - All components plugged into the same OUTLET. Not the same circuit! Having multiple outlets on the same circuit caused enough 'Difference of Potential' between the Outlets themselves (Even though it was probably Mili-Volts) to get Amplified and fed back to the Bass Bins causing the Dreaded HUMMMM.

 

My system is dead quiet now with 114db Horns and 104db Bass Bins. Every house is different and every solution is different depending on the components, wiring etc. --- You have to be willing to completely disassemble your system and track a 'Solution' down....  It's not that you have a 'Problem', because Mili-Volts are not a problem unless an Amplifier is Amplifying  the Signal and playing it out your Bass Bins. Everything can be perfect according to an Electrician, EE or an Amp designer, but you may still Have 'Ground Loop Hum'. You have to keep trying things until you find a solution for your system.

 

Everything can be perfectly Safe, Problem free, Right up to Code and hum like a Banshee....It's up to you to find a solution, because no one will  help you!

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The solution turned out to be a high quality extension cord from one Amplifier to the same outlet as the other Amplifier and Pre-amp. IOW - All components plugged into the same OUTLET. Not the same circuit! Having multiple outlets on the same circuit caused enough 'Difference of Potential' between the Outlets themselves (Even though it was probably Mili-Volts) to get Amplified and fed back to the Bass Bins causing the Dreaded HUMMMM.

 

The LOOP

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The solution turned out to be a high quality extension cord from one Amplifier to the same outlet as the other Amplifier and Pre-amp. IOW - All components plugged into the same OUTLET. Not the same circuit! Having multiple outlets on the same circuit caused enough 'Difference of Potential' between the Outlets themselves (Even though it was probably Mili-Volts) to get Amplified and fed back to the Bass Bins causing the Dreaded HUMMMM.

 

The LOOP

 

Not sure what you mean here, as yes I identified this as the Loop. Your solution of a Coax and Optical cable isolation would NOT have fixed this problem. Also these Isolation Transformers 'Break the Signal' and rely on the transformers to successfully reproduce them on the other side.... NO THANKS from me on that Solution!

Edited by Cut-Throat
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I moved into a house about 12 years ago that had a HUGE magnetic problem on one circuit. It was so bad that if a TV or monitor were placed on one bedroom wall, the screen would completely distort and become unviewable. I purchased a Gauss probe that fit my DVM. A ceiling fan had been installed by a previous owner and he mis-wired the neutral. 

This is also why a neutral should be pulled into every box, and is now required by code. Without a neutral wire to offset the magnetic field of the power wire, induction will produce a magnetic field. This magnetic field can cause all sorts of problems with electronics.

I recently had my Dad's house re-wired and the electrician did not believe a neutral was required. The guy was a joke as an electrician. I complained to the state and the city, but they just let it slide. I had to re-wire a lot of his work. Very sloppy and lazy electrician. This is the norm rather than an exception to the rule.

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The solution turned out to be a high quality extension cord from one Amplifier to the same outlet as the other Amplifier and Pre-amp. IOW - All components plugged into the same OUTLET. Not the same circuit! Having multiple outlets on the same circuit caused enough 'Difference of Potential' between the Outlets themselves (Even though it was probably Mili-Volts) to get Amplified and fed back to the Bass Bins causing the Dreaded HUMMMM.

 

The LOOP

 

Not sure what you mean here, as yes I identified this as the Loop. Your solution of a Coax and Optical cable isolation would NOT have fixed this problem. Also these Isolation Transformers 'Break the Signal' and rely on the transformers to successfully reproduce them on the other side.... NO THANKS from me on that Solution!

 

 

 

Actually I was suggesting it as a solution for optically isolating data signals and not power cords and outlets which is why I didn't quote or reference your post, sorry for any confusion.

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... With that said Tracking down Ground Loop Hum is more 'Art than Science'. There are many causes and many solutions...

 

Bingo. Having worked on many systems I can confirm that solutions have to be worked out and sometimes it's not easy. I have never run across an issue with the house grounding although I'm sure that can be a problem in some installations but it is not common in newer houses. At least not in my experience. In most cases doing the work of finding the offending component provides the best results. I can almost say with some conviction that audio systems should be free of any noise if you have taken the time to solve all the issues.

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I moved into a house about 12 years ago that had a HUGE magnetic problem on one circuit. It was so bad that if a TV or monitor were placed on one bedroom wall, the screen would completely distort and become unviewable. I purchased a Gauss probe that fit my DVM. A ceiling fan had been installed by a previous owner and he mis-wired the neutral. 

This is also why a neutral should be pulled into every box, and is now required by code. Without a neutral wire to offset the magnetic field of the power wire, induction will produce a magnetic field. This magnetic field can cause all sorts of problems with electronics.

I recently had my Dad's house re-wired and the electrician did not believe a neutral was required. The guy was a joke as an electrician. I complained to the state and the city, but they just let it slide. I had to re-wire a lot of his work. Very sloppy and lazy electrician. This is the norm rather than an exception to the rule.

 

When visiting a relative, I noticed some problems with the way the house was behaving.

 

I interviewed some electricians, read some reviews, and after my relation's wife went to work the Electrician showed up and started looking.

 

I walked around with him, he pulled out shoddy work and mis-wiring almost everywhere he looked. His synopsis "your lucky the house didn't burn down with you in it." Six hours later the house was safe. The next day he was able to do some upgrades that my relation wanted.

 

Not an isolated story.

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They worked for you and that's what counts! ...... However, if you look at the Reviews for the link you supplied, you will see that they did not work for half of the people that bought them. They would not have worked for me as I don't even have balanced connections! ...

 

That is the problem with Ground Loops!, If you buy solutions and start applying them, you will probably be disappointed! The best thing is to try to find the source of the Ground Loop and then apply a solution to that particular source.

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That is the problem with Ground Loops!, If you buy solutions and start applying them, you will probably be disappointed! The best thing is to try to find the source of the Ground Loop and then apply a solution to that particular source.

 

Expanding on that.  Assume component A connects to B.  B also connects to C.  And C has a connection to A maybe via the power cord.  By breaking a connection between A and B, then a hum is eliminated.  Does that mean A or B is defective?  Of course not.  A defect can exist in C.  Breaking an A to B connectdion only temporarily interrupted the ground loop current created by a defective C.

 

Many then want to cure symptoms using an isolator between A and B.  Instead, one should fix the problem by first identifying it.  Anywhere an isolator is required is already inside each A, B, and C box.  Also critically important are all grounds at a building level.

 

All buildings are full of grounds that are all different.  The digital ground in an electronic box can be completely different from its analog ground, which is different from it chassis ground, different from the wall receptacle safety ground, different from a static electric ground in the carpet beneath shoes, different from the breaker box safety ground, different from the earth ground, and obviously different from floating grounds maybe found in some higher voltage appliances.

 

Some grounds may be interconnected (ie safety ground and earth ground).  And yet all remain electrically different.

 

Grounds are different when each ground addresses a different problem. Ground loops are only one example.  Interruptions from a painful static electric discharge only exist with defective grounds.  Semicondictor interface IC will withstand 2000 or 15,000 volts transients without damage ,,, only if properly grounded.

 

Grounding is an art.  Which explains why ground loops are sometimes so difficult to solve.  Many mistakenly assume grounds at two ends of a wire are electrically same.  They are not. 

 

Electricians are taught grounding only for human safety.  For example, a water pipe ground is no longer sufficient. if grounding for other purposed, then a ground wire rising up from the breaker box, over the foundation, and down to earth ground rods is also insufficient.  Sufficient for human safety.  Insufficient for other purposes.

Edited by westom
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I had a good one a little while back. I had a small hybrid pre-amp that had a low level hum. The solution was flipping the power cord. The two prong cord could be inserted both ways on the unit. One way was dead quiet the other gave slight hum. That one took some work to isolate.

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Things like lamps and the CFL bulbs can cause buzz and emit RF.  
This points out that 60 Hz hum and its 120+ Hz overtones are more likely EMI, which is quite different from RFI.  A lot of that great writing in this thread appears to be focused on EMI.  RFI seems to be completely different, and in my limited experience is frequently not helped by anti-EMI measures.  As I've noted before on the forum, I had a very annoying BUZZ (not hum!!) that was cured by putting the right kind of dimmer switch on some halogen track lighting.  That's all it took, although I spent LOTS of $$$ on isolated grounding and the like.

 

Bottom line:  Distinguish between EMI and RFI, and treat the right problem.  I don't know what many of you are calling "hum" in this thread!

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 Not a ground loop problem, at least I think, but a RF problem has been driving me nuts for awhile now. I did all of the usual things, isolate power cords from speaker cables & ICs, swapped speaker positions, etc. The weird thing is, when my stereo is off the hum only comes from the right speaker even with the speaker cable pulled out of the back. When I turn on my system, the hum changes frequency and spreads out to both speakers. I also swapped amps & it got worse.

 I am wondering if the culprit could be the shop lights I had installed in my basement. It seems to me the problem occurred shortly after I had them put in. Any suggestions?

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It strikes me that EMI is either a grounding problem or proximity to a strong 60 Hz field.  This can be a real challenge if it originates or is transmitted through walls or the building structure.  One thread many years ago tracked it down to electrical cabling built into the wall in the corner of a high-rise apartment.

 

This signal is airborne, likely to be picked up by the speaker's crossover coils, and therefore can't be eliminated by disconnecting speaker cables even from the amplifier!  Because an airborne signal is omnidirectional, anti-magnetic sheeting doesn't seem to work, or not very well.

 

RFI often comes much earlier in the audio chain.  I once had to tackle it by shielding the base of a tonearm, or aluminum foil layered in behind the preamp, wrapped around where the RCA plugs enter the pre.

 

Dimmer switches are a notorious source.  I once eliminated a raspy buzz by changing a wall on-off dimmer paddle switch from one labeled "incandescent lights only" to one for transformer-based halogen lights.  This is critical to check out.

 

Grounding rather than RFI, a loose connection in the RCA plugs or their wiring inside the pre back panel.

 

RFI and loose connections will change as you walk around the room or wave your hand near the offending parts.  EMI is not affected by these actions in my experience.

 

Hope this helps.

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