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.
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Steve Walker
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Steve Walker wrote:

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.
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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.
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Steve Walker wrote:

OK then the loop shouldn't be the problem.

I noticed you said CFLs, they are VERY noisy rf wise.

As a test to see if it's the wiring in that room you could run a lead over to another room or neighbors house and see if you still get the hum in the room.
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On Fri, 24 Dec 2010 08:02:22 -0500, Steve Walker

Steve, I just saw the original post and have more information now.
Are you sure that the existing ground rod is proper and working, and that all connections to it are corrosion-free? I've felt warm ground rods where corrosion had build up between the connector and the rod, giving some resistance. It looked good but didn't function well.
-- Remember, in an emergency, dial 1911.
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On Sun, 26 Dec 2010 07:35:48 -0800, Larry Jaques
*Snip*

If your ground rod has enough juice running through it to get warm you have *SERIOUS* issues someplace, there should not, under un-faulted conditions, be any current going to ground.
H.
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On Sun, 26 Dec 2010 13:26:26 -0400, Howard Eisenhauer

With all the extra circuits someone ran in the house during bedroom addons, the ground had a 40VAC tingle to it. Subsequent circuit tracing found multiple problems and we fixed it. That Old House was built in 1939 and it had the full knob & tube wiring, complete with ceramic screw-in fuses. When I redid the front bath, I found roughsawn 2" x 3" redwood and cedar studs holding it up.
-- Remember, in an emergency, dial 1911.
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Larry Jaques wrote:

Whoa! Something else was very wrong. Ground connections & rods carry current ONLY under fault conditions. The normal, fault-free, condition is that the neutral carries all the load, including the service neutral back to the pole. A current-carrying ground means that the service neutral has a fault. Either missing/disconnected or a high-resistance connection.
Bob
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wrote:

WRONG. Metal water piping is required to be bonded to the grounding electrode system -- this is not in order to ground the *electrical* system, but to ground the *plumbing* system to ensure that the pipes cannot become live.
OP: Ignore this dangerous advice. DO NOT disconnect the water piping from the grounding electrode system. The remainder of the post is good sense, but this is dangerous.

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On Thu, 23 Dec 2010 22:39:36 -0500, Steve Walker

You are SURE the receptacles are not wired backwards?
Are the lights flourescent? If so, they NEED a ground
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On 12/23/2010 23:03, snipped-for-privacy@snyder.on.ca wrote:

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.
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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
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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.
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WB
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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.
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Steve Walker wrote:

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.
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On Fri, 24 Dec 2010 07:39:36 -0500, Steve Walker

Impossible if the voice coils were open circuit - because there would be no current flow, and therefore no magnetic field generated. If there is a crossover of some sort, it could be a possibility.
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snipped-for-privacy@snyder.on.ca wrote:

Yup, VERY strong possibility, there is a big magnetic field from something in the house, and it was getting into the big coils in the crossover network, which are typically air-core to avoid saturation.
Jon
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More likely power lines outside carrying the high current and having a large field intensity.
I had a pair of corner mounting wall speakers that one developed some hum. It was a bad DC supply for the main magnet coil. Yea - not permanent magnets but DC magnets.
Martin
On 12/24/2010 7:02 PM, Jon Elson wrote:

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wrote:

OK, so not "bare speakers" but "speaker systems" with crossover networks - which are tuned tank circuits, to some extent, and can pass significant current within themselves at certain frequencies. A "bare speaker" could NOT POSSIBLY exhibit the behaviour, under ANY conditions.
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