OT: House wiring ideas needed

My brother bought a house 2 years ago, and remodeled the basement. Older
house, no ground wires on the overhead lights. We rewired just the wall
sockets with grounds, grounded at the box. 6 outlets along one wall, and
the ground at the last outlet is also attached to the incoming water
pipe. Did not do overhead lights, as ceiling tiles nailed up. His band
had a practice there Monday, and the 60 Hertz buzz was unbearable. I
went there today to see if a bad ground existed and maybe do some
testing. All wall socket wiring is good and correct. Here's where I am
stumped. None of the amps buzz at all without inputs applied, even at
max gain. (all amps are pro grade, no cheap stuff). plug a guitar in,
and crank up the gain, unbearable buzz. Seems to be depending on where
and what orientation you are holding the guitar. High end guitars, new
pro grade cables. Also, plugging in a cable to any amp, without a
guitar, generates a buzz. Bring it near an overhead light, on or not on,
the buzz gets much louder. Same goes for any ungrounded device in the
basement, on or not. Put a Klipsch Heresy speaker near the wall wiring,
no leads attached, it will buzz. There are dead spots, where you can
hold a hooked up guitar, with very little buzz. What to do next? They
have never had this problem when practicing any where else. They have
been together about 25 or 30 years, and know their equipment, none of it
, other than some of the guitars, are older than 5 years, and it is all
high grade stuff.
Reply to
Steve Walker
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Welcome to MI Hell....
BTDT. What you are getting is VERY common. The grounds HAVE to be single point. IE: you ground them ALL at the box. With your ground at the box and at the water pipe you have a nice ground loop RF generator.
First thing is to remove the ground at the water pipe. Then ground ALL the circuits to the box. If the lights are in metal boxes ground them as well.
This will help a LOT.
Check the ground path on the amps. Most have a separate ground stud that gets grounded to your single point as well. For this you just use some good copper and ground each one.
Reply to
Steve W.
You are SURE the receptacles are not wired backwards?
Are the lights flourescent? If so, they NEED a ground
Reply to
clare
Probably not your problem. but my friend was getting a hum in his recording laptop till he disconnected from the ground. Not saying it's a good idea and the comment below may well have been the problem at the location as the building had been built on the fast track for the army around WW2 and wiring upgrades probably weren't modern code. Karl
Reply to
kfvorwerk
Judging by the ground lead to the water pipe decision, I suspect that there are likely other obvious mistakes that were interpreted as "logical conclusions" during the wiring job.
In many places, this is a bad time of year to be without shelter/homeless.
It was all sounding fairly reasonable up to the point where bare speakers hum.
You may have a hum in that space/room that you thought was coming from the disconnected speaker(s).. but it isn't/wasn't.
Reply to
Wild_Bill
Are the "bare speakers" or are they speaker boxes with integral amps?
Reply to
Dennis
Bare speakers. My guess is the voice coils were/are picking up a strong 60 Hz signal from the wiring. Why so strong, I don't know.
Reply to
Steve Walker
The return path for electric circuits should be right next to the supply path to keep electric fields low. The ground you added is not necessarily the problem. It is more likely the return path.
This happens most often with three way switches.
Dan
Reply to
dcaster
The additional ground to the water pipe was my brother's friends doing. I forgot to mention that I disconnected it. The hum coming out of the amps still exists.
Not to worry. I did the rewiring of the wall outlets. It was done correctly, and inspected by a licensed electrician. The friend added the ground to the water pipe afterward.
That's what I thought. No idea why the bare speaker picked up a hum.
The hum coming out of the amps only occurs when any of the guitars are hooked up. All pro grade stuff.
Reply to
Steve Walker
Yes. White wire to large side of plug, black to smaller side.
Yes they are, CFL, but they weren't on. I have no idea about how they are wired yet. Tiled ceiling.
Reply to
Steve Walker
I forgot to mention, I disconnected the water pipe ground. That was done after I did the outlets, by a friend of his.
Ceiling light rewiring is next on the agenda.
All the amps have 3 wire plugs.
Reply to
Steve Walker
I don't think that you can substitute a cold water pipe for a ground rod. I think that you need to install a proper ground rod near the service entrance. While you're at it, check for corrosion at the service entrance box.
Reply to
Denis G.
rewired just the wall
the 60 Hertz buzz was unbearable.
plugging in a cable to any amp, without a
Bring it near an overhead light, on or not on,
OK. This tells you:
1) Something is wired incorrectly, no matter who installed and inspected it. It only happens in this basement.
2) From the symptoms stated, you want to look at the neutral bonding and grounding at the box. If a visual inspection does not reveal a problem, put a load on the branch and measure the voltages, line to neutral, line to ground, and neutral to ground. Something will point to the problem.
Put a Klipsch Heresy speaker near the wall wiring,
This is bizarre. It takes lot of current to push a woofer, and the voice coil is generally well shielded magnetically. If there is enough of an externally generated magnetically field to move the woofer, there is a enormous current flowing in your walls somewhere.
it is all
It is a bunch of guitar amplifiers ;)
Kevin Gallimore
Reply to
axolotl
Remember the safety ground must not carry any current. I think you will find that your safety earth is a return path for some load. (where neutral and ground are swapped). Put a current probe on the safety earth at the box. Once current is detected, start disconnecting loads until it stops, then you would have found your problem. You may have more than one fault.
Neutral and ground can only connect at one place, the entrance point. Furthermore the safety earth must be good connection to true earth. If it is resistive, the current it is carrying will create a voltage drop across that resistance. That reflected voltage would then be interpreted as noise by the electronics. Steve
house, no ground wires on the overhead lights. We
along one wall, and the ground at the last outlet is
ceiling tiles nailed up. His band had a practice there
bad ground existed and maybe do some testing. All
amps buzz at all without inputs applied, even at
crank up the gain, unbearable buzz. Seems to be
guitars, new pro grade cables. Also, plugging in a
overhead light, on or not on, the buzz gets much louder.
Heresy speaker near the wall wiring, no leads
guitar, with very little buzz. What to do next?
been together about 25 or 30 years, and know their
years, and it is all high grade stuff.
Reply to
Steve Lusardi
I agree. The only thing left is the overhead lights, or....
.......something here. This I have not done. Another responder suggested ground rods near the service entrance. This will be done this coming week.
Talked to my brother, who heard the speaker sound, I did not check it. He says it's a faint buzz, inaudible more that a foot or so from the speaker.
Yeah, I know. I should have said it's all newer name brand amps, with 3 wire plugs.
Reply to
Steve Walker
The water pipe ground has been removed. Ground rod will be done this week. Corrosion check also. thanks
Reply to
Steve Walker
Thanks for the suggestion. Ground rod will be installed this week. Also will be cleaning all the old connections at the service entrance.
Reply to
Steve Walker
The magnetic path in the speaker is shielded. It would take a very strong alternating magnetic field to produce sound. One that would damage electronics.
Reply to
Michael A. Terrell
He may hear a buzz, but it isn't generated by the speaker. The cone will focus ambient noise and make it louder if you are near the focal point. Since the cone isn't a parabolic, it isn't a well defined spot.
Reply to
Michael A. Terrell
THAT makes excellent sense!! Next time I'm over there, I'll check that out. Thanks Michael. One less puzzle to think/worry about.
Reply to
Steve Walker

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