Guitar Noise

I have my guitar wired up in a sort of star ground where every component's = ground is tied to a single spot on a pot(the typical configuration basicall= y). I have the bridge grounded which grounds the strings and I have the jac= k hooked up properly.

When I do not touch the guitar it hums and makes a sort of static noise sim= ilar to the sound of an amp and cable when the guitar is not plugged in(or = the sound you hear right when someone plugs in the guitar). When I touch an= y thing grounded it becomes silent.

The only explanation seems to be that the guitar is not grounded properly a= nd when I touch it I am providing a better path to ground.=20

I've measured from the ring plugged of a cable plugged into the guitar to h= ardware on the guitar and got < 1 ohm so it seems the guitar is grounded pr= operly.

Now, I want to say that when I take it outside my house I do not have this = issue.

Unless someone can come up with a good reason why the guitar wiring might b= e wrong(I doubt it since the < 1 ohm thing should be proof enough it is gro= unded) does this mean the house has a wiring issue? If so what could it be?= Could earth ground and neutral being significantly different be enough(may= be a bad transformer or something?)?

Reply to
Bobby Joe
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s ground is tied to a single spot on a pot(the typical configuration basica= lly). I have the bridge grounded which grounds the strings and I have the j= ack hooked up properly.

imilar to the sound of an amp and cable when the guitar is not plugged in(o= r the sound you hear right when someone plugs in the guitar). When I touch = any thing grounded it becomes silent.

and when I touch it I am providing a better path to ground.

hardware on the guitar and got < 1 ohm so it seems the guitar is grounded = properly.

s issue.

be wrong(I doubt it since the < 1 ohm thing should be proof enough it is g= rounded) does this mean the house has a wiring issue? If so what could it b= e? Could earth ground and neutral being significantly different be enough(m= aybe a bad transformer or something?)?

This is whats good about balanced inputs, the problem would simply vanish.

Possibles include a bad connection somewhere in the gorunding, eg less than perfect sockets or damaged cable ends. Also inadequate cable screening. There are others too, you really need to just test them all.

NT

Reply to
NT

"Bobby Joe"

I have my guitar wired up in a sort of star ground where every component's ground is tied to a single spot on a pot(the typical configuration basically). I have the bridge grounded which grounds the strings and I have the jack hooked up properly.

When I do not touch the guitar it hums and makes a sort of static noise similar to the sound of an amp and cable when the guitar is not plugged in(or the sound you hear right when someone plugs in the guitar). When I touch any thing grounded it becomes silent.

The only explanation seems to be that the guitar is not grounded properly and when I touch it I am providing a better path to ground.

I've measured from the ring plugged of a cable plugged into the guitar to hardware on the guitar and got < 1 ohm so it seems the guitar is grounded properly.

Now, I want to say that when I take it outside my house I do not have this issue.

Unless someone can come up with a good reason why the guitar wiring might be wrong(I doubt it since the < 1 ohm thing should be proof enough it is grounded) does this mean the house has a wiring issue? If so what could it be? Could earth ground and neutral being significantly different be enough(maybe a bad transformer or something?)?

** The problem is not grounding as such bit a LACK of good shielding.

Either the internal wiring is not fully shielded or the pickups are not metal cased and grounded.

What you describe is very common with many electric guitars that have plastic cased pickups and unshielded wiring.

Once you ground your body, most of the noise goes - so you have no real issue.

The explanation is that a grounded human body acts as an electrical shield.

.... Phil

Reply to
Phil Allison

You might consider posting to alt.guitar and/or alt.guitar.amps with this question. Lotsa very knowledgeable and even professional luthier/electronics ppl on both groups.

nb

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Reply to
notbob

"Luthitronics"?

Or

"Lutetronics"

Reply to
AnimalMagic

heh....

Sure, why not. You'd be astonished how many ways 2 or 3 pickups on the same electric guitar can be wired. I know I am. ;)

nb

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Reply to
notbob

What happens when you reverse the AC line phase on the amplifier? Many amps have a powerline phase reversal switch. Gets worse if you have preamp and power amp separated by some distance (ie sound systems where mixer is in the house and power amps are by the speakers). Here you ground the power amps and often have to lift the grounds on the mixer. Otherwise currents tend to flow in the shield and cause hum... Proper use of grounding is an art-form, not unlike designing for EMC.

Reply to
Oppie

alt.guitar.amps used to be great - now it's overrun with political posts.

Reply to
Sofa Slug

This one isn't!? ;)

nb

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Reply to
notbob

"notbob"

** The few knowledgeable posters on alt.guitar.amps left years ago.

The NG is now completely swamped with f****it trolls.

BTW:

I am a guitar amp and electric guitar professional ( with 40 years experience ) and the OP will not get a better reply than mine.

... Phil

Reply to
Phil Allison

I don't know because my amp doesn't have that.

Obivously if two devices have different grounds then there will be an issue in general. This shouldn't be the case since it is just one device.

Reply to
Bobby Joe

I'll do some tests and report back...

Reply to
Bobby Joe

"Booby Joe"

** Don't bother.

Nobody needs to hear your asinine opinions.

.... Phil

Reply to
Phil Allison

"Booby Joe"

** Piss off to hell - you know nothing idiot.

.... Phil

Reply to
Phil Allison

I thought we had a "be nice" policy here.

Reply to
Oppie

"Oppie"

** There is NO policy to be nice to fuckwits or trolls.

Fuck off - you stinking IMBECILE.

Reply to
Phil Allison

general. This shouldn't be the case since it is just one device.

It's not a ground loop issue, it's EM noise pick up from the surroundings eg your house wiring which is why it reduces when you go outside. Fluorescent lights are particularly bad.

It's worse too with single-coil pickups (you didn't mention which type you have). If you have noisy humbuckers they're either incorrectly wired or faulty.

Shield your pickups - if you want magnetic shielding you'll need so-called mu-metal sheet (available on eBay) - and use shielded wire for all connections with the screen terminated back to your star earth.

Some guitars have the entire wiring cavity shielded, this is a fiddly job to DIY.

BTW, connecting your bridge (& strings) directly to signal ground can be a safety hazard if your amp develops a fault that causes the signal ground to go live then your guitar and then you! It's not generally recommended. Or even if you play in a venue with bad earthing, the PA equipment can go live (eg the microphone cases) - something about a 240V belt on the lips tends to make you forget the chords!

HTH

Chris.

Reply to
Chris

"Chris = IMBECILE "

** Correct.

** How absurd !!!

Magnetic shielding will STOP the pickup from working.

- and use shielded wire for

** Star earthing a guitar is totally absurd.
** Using tin plate or brass sheet it is do-able.

** Utterly absurd CRAP !!!

** 99% of all electric guitars have the strings earthed and they NEED to be !!

A fault that puts live on chassis will get you soon as you touch the jack plug in the guitar, a metal knob or the amp itself.

Wot f****it advice.

... Phil

Reply to
Phil Allison

ob

Also, handy for sealing junctions, etc. use 1 inch wide copper tape from 3M, be sure to use the 'conductive' adhesive form.

Cut the brass shim to handy sizes, bend appropriately, lay into the cavity, bridge gaps and curves too difficult to shape the shim to with the tape. You can solder to the tape, or to the brass. Makes one good 'almost' Farady shield that's easy to construct.

Be prepared for sticker shock at the price of the copper tape. I used to pay $36/roll That's a bargain today.

Reply to
Robert Macy

Yes, if you shield the pole pieces - you can shield it everywhere else but the top. IIRC the Fender "Lace" sensors have something similar to reduce their susceptibility to EM noise (willing to be corrected).

It's an option, not saying it's *the* best way to go. Personally I prefer humbucking PUs in the Strat/single-coil form factor.

The OP had it there already (hence "*your* star earth"), saves confusing him/her further.

A signal path to earth is good, sure.

Of course it does - never said otherwise.

But what if it develops during the performance, or is intermittent?

What if you touch another piece of gear that is badly earthed while playing or holding the strings?

So *you* say. I 'earthed' my bridge with a 100k resistor in parallel with a 100n cap. Noise is bearable and I no longer get belted by badly earthed PA gear, it just tingles now.

Chris.

Reply to
Chris

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