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Why ground wire?
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10123&t=32416		 Page 1 of 1
Author:  jeff.scott [ Thu Jun 02, 2011 12:58 pm ]
Post subject:  Why ground wire?
I was so excited to have strings on my first build that I wired the pickup directly to the output jack, tuned it up and plugged it in. I couldn't believe the crisp tone from P90s and an all maple guitar - like no other axe in my collection.

I had been playing for almost an hour when I realized that I forget to add the ground wire. It certainly didn't need it. The sound was pure and clean and no buzz at all. I got to thinking that since wood is a great insulator, and my hands are in no way touching the electrical componants of the guitar, why put yourself at risk by adding a ground wire?

Just wondering how the lack of ground wire would affect a Strat style (single coil) circuit, or a Les Paul (humbucker) circuit?

J
Author:  the Padma [ Thu Jun 02, 2011 1:09 pm ]
Post subject:  Re: Why ground wire?
Actually wood is a conductor...not a very high one, but a conductor non the less.

The ground wire is simple...something goes wrong in your amp ...say a power surge rips through and guess what.... daz right...you may get shocked or fried. You are actualy puting yourself at risk by not adding a ground wire.

Just something to think about.


blessings
duh Padma
Author:  mdubs712 [ Thu Jun 02, 2011 8:43 pm ]
Post subject:  Re: Why ground wire?
add a ground wire to what? your strings?
Author:  Chameleon [ Thu Jun 02, 2011 10:03 pm ]
Post subject:  Re: Why ground wire?
mdubs712 wrote:
add a ground wire to what? your strings?

That's a good point, having your ground connected to the bridge, and thus the strings, is what makes your guitar vulnerable to electrical shock. On some guitars you'll notice less noise when your hands are touching the strings and when you lift them off, hear a mild buzzing.

The author of the guitarnuts website talks about adding a 400V capacitor to your wiring schematic to prevent electrical shock in the event of an amp failing on you. http://www.guitarnuts.com/wiring/shielding/shield3.php scroll down to "Why a 400V Capacitor?"
Author:  johnparchem [ Thu Jun 02, 2011 11:25 pm ]
Post subject:  Re: Why ground wire?
I agree with Chameleon, adding the ground to your bridge and thus your strings increases the risk of a shock. Before the ground is added the bridge and the strings are nicely isolated from all of the electrical components. Once the ground wire is added you are in effect touching a wire that goes right to the amp everytime you touch the bridge or a string. An amp problem may very well send 110V in the US or 220V in Europe through the ground wire right to the bridge or strings. The ground is added to get rid of 60 cycle buzz on passive pickups. In guitars with active pickups the bridge is not wired to ground. If you have a clean sound without the ground wire leave it off.
Author:  the Padma [ Thu Jun 02, 2011 11:28 pm ]
Post subject:  Re: Why ground wire?
Hmmm...
Author:  mdubs712 [ Fri Jun 03, 2011 1:31 pm ]
Post subject:  Re: Why ground wire?
Ok here is my understanding of guitar wiring. If you get sound from your guitar through the amp... its grounded. Circuits are not complete without being grounded, there is always a lot of confusion with the so called ground, and it may continue with me although i believe the info i have read to be accurate. as simple as it can be put, a circuit is a circle, if u put your pickups in that circle the north side of your coil is the "in" and the south side is your "out" granted its a circle you can label it however you'd like. Your "out" is your ground if the ground inst wired then the circuit is not complete. All your grounds lead to the ground end if your pick up jack and from there into your amp and from there into the ground of your amp and from there into the ground of your power source and so on. Feel free to correct me if i am wrong because i would really like to know! Its all about resistance and making sure you have more resistance than the other ways of completing a circuit.

mike
Author:  johnparchem [ Sat Jun 04, 2011 10:29 am ]
Post subject:  Re: Why ground wire?
mdubs712 wrote:
Ok here is my understanding of guitar wiring. If you get sound from your guitar through the amp... its grounded. Circuits are not complete without being grounded, there is always a lot of confusion with the so called ground, and it may continue with me although i believe the info i have read to be accurate. as simple as it can be put, a circuit is a circle, if u put your pickups in that circle the north side of your coil is the "in" and the south side is your "out" granted its a circle you can label it however you'd like. Your "out" is your ground if the ground inst wired then the circuit is not complete. All your grounds lead to the ground end if your pick up jack and from there into your amp and from there into the ground of your amp and from there into the ground of your power source and so on. Feel free to correct me if i am wrong because i would really like to know! Its all about resistance and making sure you have more resistance than the other ways of completing a circuit.

mike



you are right about how the ground to the coil works. In a lot of guitars the bridge is also grounded which grounds the strings as well. The steel strings are great at picking up 60 cycle hum and is able to transmit that hum to the pickups. The ground wire drains that 60 cycle away.
Author:  mdubs712 [ Sat Jun 04, 2011 1:29 pm ]
Post subject:  Re: Why ground wire?
johnparchem wrote:
you are right about how the ground to the coil works. In a lot of guitars the bridge is also grounded which grounds the strings as well. The steel strings are great at picking up 60 cycle hum and is able to transmit that hum to the pickups. The ground wire drains that 60 cycle away.


yes I understand why they ground the bridge but I believe he didn't think his guitar was grounded and i was just saying if there's sound its grounded. People think its bad to ground strings to remove the hum because it increases your chances of getting shocked, but it still comes down to resistance adding the ground to the bridge and touching your strings is still a dead end for that circuit because there are many other paths of less resistance... unless your body has less resistance than the normal wiring your not going to be the path it will choose. also people say you will get shocked from touching other electrical equipment while touching grounded strings its the same case. circuits are predictable its not magic.

mike
Author:  Chameleon [ Sat Jun 04, 2011 1:39 pm ]
Post subject:  Re: Why ground wire?
Yeah I guess it makes sense that the circuit was grounded somewhere because even humbuckers will be noisy as hell without being grounded. Maybe he accidentally grounded it somewhere in there.
Author:  ledbthand [ Sun Jun 05, 2011 2:42 am ]
Post subject:  Re: Why ground wire?
Wasn't KISS's song Shock Me written because of a bad ground wire hehe
Author:  jfmckenna [ Mon Jun 06, 2011 2:44 pm ]
Post subject:  Re: Why ground wire?
You most certainly are grounded if you can hear your guitar through your amp. In your case the P 90 has two wires, the hot wire and the shield that surrounds it. You soldered the hot wire to the bigger external lug of the jack that connects to the tip of your cable plug and the shield wire to the smaller internal lug that connects to the sleeve of the cable plug, that's the ground.

On all my electric guitars I wire in tone and volume pots and you know what? I never use them. I'll probably build one like you did one day. Two pickups to a switch and a master volume or maybe just two volume's and right out the door.
Author:  jeff.scott [ Mon Jun 13, 2011 6:59 am ]
Post subject:  Re: Why ground wire?
ledbthand wrote:
Wasn't KISS's song Shock Me written because of a bad ground wire hehe



Ok, I'm the KISS expert here. Yes, Ace Frehley was coming down the metal stairs (part of their 1977 set) and when he touched the steel railing he got a big jolt of voltage and was actually unconscious for about 10 or 15 minutes. He came back and played the show with burns on his hands. What a trooper.

After that the band invested in very primative and very expensive wireless units. "Shock Me" was written after that as well.

I use wireless as much as possible for the freedom, so I don't worry much about electric shock at gigs.

J
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