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PostPosted: Fri Sep 15, 2006 3:17 pm 
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Location: Nashville, TN
The 600 sq. ft. space was previously an apartment. My electrician removed all the old stuff (including the breaker box), ran new romex, new (plastic) enclosures. I'm not sure if he incorporated star ground or not, but certain outlets are on their own IGR circuit, separate from lights/HVAC, etc.

The HVAC is also brand-spankin' new (1.5t Trane).

So....my guitar hums. This happens to be my profession, so I know a good room from a bad one...and this is not good enough.


Last edited by chrisgraff on Sat May 12, 2007 2:35 pm, edited 1 time in total.

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PostPosted: Sat Sep 16, 2006 3:46 am 
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Chris,

I'll post here so all can see, instead of just PM.

In addition to what I've asked so far...

What type of lighting do you have? Florescent, Halogen, or regular bulbs. Do you have a dimmer anywhere in your electrical system?

Do you have more than one guitar you can try? Try different cables (how long is your guitar cable?) Have you tried placing your cabinet in another spot in the room?

Have you tried the trick w/ aluminum foil...CAREFUL...you can shock the shit out of yourself.

You've already said you have a new ground. Is all 8 ft. of it all the way in the ground?

Quote:
I don't hear radio signals at all. But I'm not sure that would rule out RFI. The tech power (with isolated ground) is definitely better than the other outlets, in that, when I let go of the guitar the hum does NOT get louder.

Something else...an AM radio, plugged into tech power, will pop when I flip the lights on & off. Mind you, the radio is plugged into tech power, which should be totally separate from everything else. What I don't know, is whether that's an indication of ground problems or RFI. It is a radio, after all.

_________________
-Chris Graff


Double check all those electrical connections. Sounds like your lights are also on the tech power???


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PostPosted: Sat Sep 16, 2006 8:57 am 
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There are halogen (line voltage) in the lounge. No dimmers whatsoever in the building.

I haven't tried another guitar or amp, but I hauled the two over to my neighbors tool shed (slightly quieter), and my buddy's studio (much quieter).

I should mention that when both pickups are on (middle pos./Telecaster), the hum goes away completely. Yet, an AM radio plugged into the tech power outlet(s) will pop when the lights are switched on/off. Lights are not on the tech power circuit. Nothing on that circuit but the tech power outlets

Here are some pics:

• Old groundwire (disconnected, I assume) / New groundwire

• New groundwire...installed correctly?

• lounge/kitchen

• Circuit breaker. Waterheater will not be installed (hot water will come from the house)

• Tech power outlets. Comments?

Image
Image
Image
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PostPosted: Sat Sep 16, 2006 9:04 am 
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Aaronw wrote:
Chris,

Try different cables (how long is your guitar cable?) Have you tried placing your cabinet in another spot in the room?


Yes, I've tried both Mogami and Zaolla cables; also tried the amp in several locations within the building.

Aaronw wrote:
Have you tried the trick w/ aluminum foil...CAREFUL...you can shock the shit out of yourself.


Yes, tried that one. No change in hum. This would lead me to believe there is not a ground problem

Aaronw wrote:
You've already said you have a new ground. Is all 8 ft. of it all the way in the ground?


See pic. You tell me :wink:

Aaronw wrote:
Double check all those electrical connections. Sounds like your lights are also on the tech power???


I'll ask the electrician to do that. Lights definitely separate from tech power.[/i]


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PostPosted: Wed Sep 20, 2006 12:38 pm 
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Chris,

Looking at your panel labeling...you've got things like the fridge on the same leg as some of your isolated circuits.

Most panels, alternate the load between the two legs coming into the panel (so you can have 220 circuits for like HVAC, etc.).

If you're not sure what I mean, give me a few minutes, I'll go take a picture of my subpanel since the cover is off...


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PostPosted: Wed Sep 20, 2006 12:43 pm 
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Here you go. Here's picture of the buzz bar down the middle of a panel...


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PostPosted: Wed Sep 20, 2006 1:35 pm 
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All those green home-run grounds! I'm Jealous!

I noticed that too about the fridge. I can't even begin to express the frustration.

I've come to the conclusion that I hired the text-book example of who NOT to hire. So I paid him, and sent him on his way.

Gotta find someone else to fix this mess.

On another note...

I tried my guitar+pedalboard+amp yesterday. I think I have Nashville's noisiest studio! :shock: Seriously, when I plug the guitar cable into the amp, then wave the other end over the pedalboard - the hum gets louder.

RFI or ground problem? Still gotta determine that.


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PostPosted: Wed Sep 20, 2006 1:43 pm 
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Quote:
All those green home-run grounds! I'm Jealous!


You Bet! Every single outlet in the studio has it's own ground wire back to the panel. With a #2 AWG wire running to the 5/8" copper ground rod.

Since you're local, drop me a PM. Maybe we can figure out the issue.

It's also possible you just have bad power or transformer coming into the house. You may have to install some filters or transformers to isolate it completely.


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PostPosted: Wed Sep 20, 2006 1:45 pm 
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Speaking of power. Do you have a voltage meter? What are you reading for voltage?


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PostPosted: Wed Sep 20, 2006 1:52 pm 
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I'll get back to you...my v.m. is packed away in the attic somewhere.


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PostPosted: Mon Feb 05, 2007 5:51 pm 
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Here's the latest...

I have power lines/poles running alongside my building - maybe 10 feet away or so. A certain number of those poles (possibly all?) are supposed to be grounded. I tech who was over here today noticed that one of the poles (the only one with a ground wire) had it's ground wire snipped. Whatever's up there on those lines is finding ground at my house!! :shock:

I can't imagine that the electric co. wouldn't fix this. Could my guitar hum problems be over???

Stay tuned!


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PostPosted: Thu Mar 15, 2007 3:40 pm 
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another $800 spent, exactly 0dB improvement. I searched and searched to find "the best guy in town". My business is at a standstill until I get this resolved.


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PostPosted: Thu Mar 15, 2007 11:32 pm 
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Hello Chris.

Another $800. Ouch. Don't feel bad. I've run into a ground loop issue myself over the past few weeks. Trying to avoid having to spend thousands myself to resolve it. I'll let you know what I find in my resolution.


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PostPosted: Thu Mar 15, 2007 11:39 pm 
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Chris, have you tried a GROUND-LESS outlet yet? (have the electrician make a portable one for you) I use those during PA setup on location. Whenever there's a hummingbird, I'll kill it with such ground-less connection.


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PostPosted: Fri Mar 16, 2007 12:24 am 
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There seems to be some debate whether the electric poles running next to the building need to be grounded. There is one apx. 30 meters behind the building with a large can transformer. It has a groundwire that is connected. What is interesting is that my cheap (speaker) gaussmeter, shows that as quiet; as I walk away from the transformer (walking parallel to the line), the hum gets louder.

The next pole towards the street sits off the front corner of the building. It is not grounded. Finally the one on the street has a groundwire sticking out of the ground, but is not connected up the pole.

The electric company says that A) they are only required to ground four poles per mile, and B) they usually only ground the poles with transformers.

This last electrician wants to install an isolation transformer, as a next step. If it corrected the problem, I'd spend the $$$ in a second. However, I'll be extremely angry/disappointed if I spend the money for no benefit.


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