Can moving wire location at circuit breaker reduce hum?

So, we are talking about a mechanical hum that you can hear or feel at the amp itself, right? OK, that’s a sign of DC on the line.

If you move to another "leg" of the panel it may fix the problem but only if the source of the DC is on another circuit. See if you can locate the source which is often something like LED power supplies or some wall wart somewhere or old dimmer switches. If the problem is on the same circuit as your audio gear then no amount of moving a breaker around will fix it.

If you are sure the source is not on your circuit, then try moving to another leg. Panels alternate legs horizontally, so pick a new location that is off by odd row numbers. 1, 3, 5, 7, etc. If you move horizontally or an even number you will stay on the same leg.

Of course, they also make DC blockers specifically for this purpose.

Hi

Looks like you have a pesky one. The way you described it is a little confusing though. Does the hum happen constantly or is it “oftentimes”?  Is the amp the only component humming or are there more?  You talked about “any component that’s humming”, what else is humming?  The fact that moving the amp to another room stops the problem tells you it’s not the amp. Have you tried different outlets in the original room?  To find out if the wiring is at fault, you can try a simple, inexpensive wire tester such as this one: Klein tool RT110 receptacle tester. Moving the wire should be your last result. Good luck. 

First make sure there are no motors on that circuit. If not, then use a receptacle tester (the one that plugs in with three lights) and see if it is properly wired. Next step is to check for an unbalanced neutral at that receptacle. Measure both hot and neutral with respect to the ground. Anything more than a few volts on  neutral to ground is not normal. Also check the hot to ground voltage at all other receptacles on that circuit. Any difference is the results of loose wiring, which can cause arcing. Any of the above will make transformers sing.

When I was building my room, I was advised that "the 2 dedicated 20 amp lines MUST be on the same phase leg. Otherwise I could get a ground loop".

Is the hum present when the component is connected to amp with RCA/XLR, or just the component into the electric outlet? Because if you just connect the component to the electric outlet and no other cables are connected to that, then you can rule out the ground loop.

@milpai  That's correct but I think you missed that this is mechanical, not electrical hum. 

Mechanical hum comes from DC on the line, not from ground loops.  DC is when the AC voltage is shifted up or down by a DC voltage.  So the AC may be 120V, but it's shifted so it's 0 crossing is no longer 0. 

Here's a great meter to use for basic testing, including Neutral voltages:

https://amzn.to/3y55cdF

Fortunately, the first test, to identify if this is caused by another electrical component is fairly simple.   Turn everything else off in the house. 😀

Flip off every breaker and make sure nothing is left on your circuit but your amps.  If the problem is gone, you know it's something else, and that's my bet, but yeah, it could be a bad neutral.

"Would swapping out the wires that go into the two separate rooms at the breaker make any difference?"

Give it a shot, you have nothing to lose!

     A lot of pro (instrument) amps have phase-reverse switches, to deal with hum issues, on stage.

     Those suggestions on the outlet wiring tester, to me, would be a good/basic place to start.

     Hots of all outlets in the room, on the same leg, in the panel/breaker box?

                                                    My 2 cents.

Ground loop you have..Tom

Thinking back over 25 years ago I had a client with top of the line Melos gear. Had the same hum issue and voltage on a line it turned out to be a coax cable hooked to a piece of gear connected to the preamp. Tom

Thanks, everyone, for your input.  I’ll pick up the tester on Amazon.

I have shut off the circuit that goes into my music room and went around testing the outlets all around it to see which ones are dead.  I’m guessing the receptacles would be in the same general area so I didn’t go to every receptacle in my house.

I’ve then disconnected everything except the amp and it’ll still hum.  I’ve had numerous electronic components hum in this particular room.  In the room just next door, dead quiet.  
 

Hair dryers, kitchen appliances, dimmers,... can cause this even by using dedicated lines for your system. One easy way to check is heat produced from the transformer when idling or with no signal (check preamp also). Try to relocate and eliminate possible suspects as advised above or get a dc blocker, it works. 

You did the test kind of backwards. :) 

Turn off all breakers but your stereo.  If your hum disappears then start turning breakers on until it re-appears. If it remains even when the only thing on it is your amps then it's most likely a wiring issue.

Thanks, Erik.  I’ll try that.

"Would swapping out the wires that go into the two separate rooms at the breaker make any difference?"

Give it a shot, you have nothing to lose!

Some people would prefer to understand the problem with say. DMM, rather than just throw “solution buccaci” at it, and hoping that they hit it..

...make sure your insurance is up to date.... ;)

Shut everything else off at the circuit breaker and still hum.  

I guess I’ll keep on living with it until I get an electrician to install a dedicated line.

Hope that will do the trick.

OP:

You still need this evaluated, regardless of a dedicated circuit. 

Also, keep in mind they do make dedicated DC blockers that are quite effective.

Concur, this is DC issue ... several DC blockers on the market:

Audiolab

Emotiva

iFi

Humdinger, Audio by Van Alstine

Let us know!!

What exactly is on the branch circuit your equipment is on? Just the other outlets in the same room, another room too, sconces, recessed ceiling, Maybe I missed it if you mentioned it earlier so I apologize if that is the case.

When dimmers are off they are not really off and they are very pesky. Disconnect the power to them and see  what happens. If your unsure turn off your breaker before you detach the black wire at the switch..

@auidiodebe When you write

I’ve had numerous electronic components hum in this particular room. In the room just next door, dead quiet.

I can see why you asked the question as you did. While using a tester is a good suggestion, the tool is often only as good as the person using it. One has to know how to interpret the results of the testing. This is what an experienced electrician can provide. But having been an industrial electric/electronic technician for many years, I’ve learned that there is great value in ‘getting your hands on it.’ I’m in the ‘what have you got to lose? camp.
I don’t know how comfortable you are working on circuits, but, let me assume from your question, that you are. You could try the following:

1. Open up the panel, throw the main breaker (for your safety)

2. Using an appropriately sized screwdriver in good condition, tighten up all the screw terminals of all your breakers (I’ll bet you’ll find more than one or two loose) —you’re just doing maintenance at this point).
3. Turn everything back on (but don’t set the clocks yet), and see if there is any change.
If the problem remains,

4. Throw the main (again, for your safety) and open up the receptacle into which you plug your amplifier. Remove the wire from one side of the receptacle; that is, we expect to find one wire coming from the panel and one wire continuing on to other receptacles on the same circuit, but this may not be the case if your amp’s receptacle is at the end of the line or is fed by a ‘drop’ from another ‘junction’ box. Let us assume it is inline, and you can break the line at your amp’s receptacle. Make sure to separate the now freed wires (you can cap them with wire nuts). You can attach volt meter and/or tester leads at this point if you prefer not working with live 120 Volts, or don’t have proper Personal Protective Equipment (PPE), which in this case would be electrically rated gloves and leather protectors, and electrically rated face shield, fire-rated clothing and no exposed jewelry, including belt buckles. (The memories are coming back to me of working in this gear in very hot spaces.)

5. Apply power. You are looking to see which line into the receptacle is carrying the power from the panel. If you only have one tester, you may have to repeat the exercise. Once you have identified the hot leads, throw the mains again (for your safety).
6. While the power is down on the circuit, if it isn’t already, connect the receptacle to the wire which comes from the panel. Plug your amp into the receptacle.
7. Apply power and turn your amp on. If it hums, the problem is in the panel or possibly ahead of it, or it is between the panel and the amp’s receptacle.
Note: You need to be very careful when you open up the receptacle and guard against the possibility that the ‘wires got crossed’ somewhere in your house’s circuitry, with a second circuit ‘back-feeding’ into your sound room’s circuit. While you have the line broken at the amp receptacle, it would be an excellent time to check for this fault. Turn your amp’s circuit breaker off, unplug your amp, attach your leads, and turn all the other other circuit breakers one-by-one. There should be no voltage on any of the leads into your amp’s receptacle from either the panel side or from ‘down stream’ side. At this point, a receptacle tester would be quite helpful, as it would report voltage found on any lead (although we would expect to find an ‘open ground’ fault on the downstream side).
I only add this note because such mis-wiring does exist, and I have been bit hard by a supposedly ‘neutral’ wire on the downstream side of ceiling light fixture while installing a ceiling fan in my own newly purchased, just re-wired house. That was when I discovered that back-feeding was a real thing, and that electricity is a force to be respected. I should add, that in my case, no fuses blew, and no circuit breakers tripped, everything appeared to be working as expected until I opened the junction box up. Be careful, go slow, get help, and go for it, I say.

Sounds like there is something else on the line or something with the ground wire.  Have you tried a cheater plug yet?  See what ese works when just that line is working.  Could be like a refrig, or something else cause the problem.

I have a system that was picking up hum when I moved into my current home, but not the previous home.  It's a custom system designed and built by a fellow I've know and used for years (Von Gaylord Audio).  When he visited after the hum was noticed, he was fairly sure  it was electrical interference.  There is a high voltage tower about 200 yards from my home.  He built me a set of shielded cables for the pre-amp to amp interconnects.  That took care of the hum.

Thank you so every much, everyone!

Is a DC blocker like the Hum X device?  If so I've got two of those and they really don't do much at all.

I'll trying tightening the screws and maybe moving the line that goes into my music room but beyond that it seems a bit scary.

On this particular line in my music room I've got other things plugged in and in the other room there are two receptacles connected to this line where a TV, amo and Amazon Firestick is plugged in.

But I get the buzz even when I unplug all unneccessary items.  I have the source components plugged into a PurePower 2000 which is connected to a different receptacle in the same circuit.  The amp goes into a RSA Maxim power conditioner but even if I plug strait i to the wall the buzz remains.

What's really weird is that not all amps will buzz.  Maybe I should have mentioned this sooner.  But more electronics have buzzed in this room.

I've got tubed headamps hum/buz, preamps emit a buzzing and even a CD transport hums.  All these components taken into the room next door and they're all dead silent.

It gets a bit frustrating at times.

I've got a cheater plug laying around somewhere so I'll try that, as well.

Cheers, all.

Mamoru

Some makes and models of amp will hum, some will hum less, and some will not hum at all when plugged in, in certain houses.  Some individual examples of a given amp may hum and others may not.  I've had no hum and variable degrees of hum from different amps, and one nearly drove me crazy: it had mechanical hum at the amp and hummed through the speakers.  I tried it in every room of the house, and it was always the same.  I also brought in 10-12 different boxes of conditioners, DC blockers, ground lifters, transformers, etc. etc., and not a single one cured the problem.  The fact that you get different results in different rooms tells me that the place to start for you is with an electrician, rather than with an extra piece of equipment.

@audiodwebe,

What amps do you have?

Mike

Plus 1 @erik_squires 

Another question, do you use LED lights on a dimmer switch? Not sure why, but I’ve issues when I used an outlet on the same circuit for a HT receiver.

All the Best.

JD

Another question, do you use LED lights on a dimmer switch? Not sure why, but I’ve issues when I used an outlet on the same circuit for a HT receiver.

I have used modern dimmers without a problem, but the older LED power supplies were awful.  The problem is they would only take power from one direction of the AC signal.  If the AC signal goes to +140 V and turns around and does -140V, and you have relatively high impedance on the wiring then you suck down one side, making it +135 to -140 and voila, DC.

OP: One other thing to consider is, how old is your house?? If those are older outlets or using back-stabbed connectors they need to go.

You can get good commercial grade / tamper resistant outlets for ~ $4 a piece.

So far in this 17 year old home I've replaced 28 light switches and about 20 outlets, including 7 GFCI outlets.  Given how many issues I found I'm glad I did. 

So I just looked online at a couple of DC blockers.  You have to be careful as the two I found were rated for 7 A or less.  If you are using monoblocks I am going to guess you are going to easily exceed this. 

My recommendation that you need to have your power evaluated by a pro stands no matter what.

If you really need a DC blocker, Audio by Van Alstine has a good one, and they allow returns.

The current culprit is a Marsh amp.  Lights but no dimmer switch.  The house was build in 2001 but I upgraded the receptacle with one of the audiophile-approved  Randy’s about a year back.

I’ve always had a problem with this room and initially thought all my gear was going bad until one day, on a whim, tried a component in another room.

One of my daughter’s friends is an electrician.  I’ll probably have him look into it.

Thanks, all.

Cheers,

Mamoru

OP:  I encourage you to replace all upstream outlets if they use backstabbed connections. Again, not suggesting you spend a lot, $4/$5 per outlet for new, commercial grade/tamper resistant.

I installed a cooktop about 3 years ago and it became nightmare of noise in my REL subs. At first, I had no idea what was making my subs hum. It wasn't a ground loop. I sent them to Pyramid Audio and they found no problem. I have 4 dedicated lines & a Furman Ref IT15 and they did nothing to silent the humming. After much research, I determined it was a DC issue caused by the cooktop. I purchased 2 Emotiva DC blockers & no noise

@jb1 That's interesting.  Was the cooktop 120V or 240V?

One of my daughter’s friends is an electrician.  I’ll probably have him look into it.

Well done on the plan.

@audiodwebe,

Here is a good article on sound and power for your home if you decide to go with dedicated circuits for your audio system.

Mike

Maybe run an extension cord from the room with the good socket as a temporary measure?

Well, you have received lots of advice but I'll throw one more at you of a bit different nature. If you decide to create a dedicated circuit then pulling wire is plain grunt work that requires no special training. If you can access everything easily you can save a lot of money by pulling the wire yourself. Why pay an electrician to do menial labor? Just be kind and leave him plenty of wire to work with on each end. Especially at the panel. Oh, and please let us know what you find. I believe there is an issue on that particular circuit. 

Get several cheater Plugs and make sure the AC ground is not connected. These are male to female AC connectors that you can disable the AC ground. Many times hum is related to to a ground loop between units. Even if everything connected to the same AC outlet you can still have circulating ground currents.

Get several cheater Plugs and make sure the AC ground is not connected. These are male to female AC connectors that you can disable the AC ground. Many times hum is related to to a ground loop between units. Even if everything connected to the same AC outlet you can still have circulating ground currents.

If the OP already knows that the amps are humming without inputs, then it is not a ground loop.
And. The OP knows that a different circuit does not hum.

These clues are very good, and going against code with a potential for danger would lead me to believe that messing with grounds is likely be best to be avoided.

I would start by getting a big heavy extension cord.  Use the cord to try different outlets.  Before you set about to fix the problem be sure you are fixing the right problem.

Cheap power outlets are plentiful out there. From way back when, I change out every outlet in the house with pro grade Leviton outlets. Same with switches. I have even had to change out some breakers because they can become weak with age.

Even if the particular outlet that your amp is plugged into has no trouble, it is in a chain of outlets, one connected to the next.

Having said this, I don’t think that there will be the described trouble from the outlets themselves, but you may discover some ’interesting wiring’ along the way.

In reference to part of your original question, "Would changing breaker positions closer to the main breaker make a difference?" That is a seldom asked question yet an interesting one. Having worked for Ma Bell in the central telephone office, this was a consideration, at least at the ground buss. We were working with negative 48 volt DC, so this might be apples and oranges in a way. The ’switch’ room, which was the brains of call connections, had it’s very own buss and power for that matter. The intention here was all about noise and circuit protection, but I wonder if the same might be said with AC.

Lastly, I would like to mention the idea of a dedicated circuit for your system. I would agree about running the wire yourself, with at least one thing in mind. The path chosen for the run should ideally be it’s own, not to be shared with other runs or existing wiring (to save some drilling).

Please keep us informed as to what you find as an answer.

@erik_squires . Would balanced power unit, like an Equitech, be any use?