Grounding Issue?

Roland

Junior Member
Messages
31
Hey I just finished wiring up my Warmoth, and electronically everything seems to be fine. Both pickups are working, and the tone and volume knob do what they're supposed to. However, when I am not touching any metal on the guitar, it buzzes noticeably. If I touch the bridge, knob, strings, etc. the buzzing stops. Do any of you know what might be causing this to happen?
 
It's not that your guitar has a grounding issue, your body does. Your body is behaving as a large antenna that's picking up and concentrating the EMI/RFI around you and in turn radiating that noise to your guitar's wiring. Then when you touch the strings/bridge/pots/etc., you ground yourself and drain away most of what you're picking up. If your guitar had a grounding/polarity problem, touching it either would either make it worse or not do anything at all. Best way to mitigate that is to use shielded cable wherever possible internally, and where it's not possible, keep the wires as short as possible.
 
Yeah that makes sense, thanks for the help Cagey. I rather foolishly thought I could put P90s in a guitar without any shielding at all and get away with it. The wires are all shielded though, if by shielded you mean that they have the rubber sleeve thing around them. I'll try shielding the pickups cavities and the control cavity. What have you found to be the most effective shielding?
 
Rubber doesn't do any shielding, it's just insulation. There may be a shield underneath that, though. It would look like a metal foil or braided wire mesh wrap, and is intended to be grounded in order to have any effect.

Unfortunately, since P90s are single coil pickups, they're never going to be very quiet. Shielding the cavities won't help. It's just something you have to live with.
 
Ok yeah I thought that might be the case. It doesn't matter, I'm fine with the 60 cycle hum because I love the tone of the pickups. For future reference though, what do you find to be the best material to shield control cavities/pickguards/etc. with?
 
Roland said:
Hey I just finished wiring up my Warmoth, and electronically everything seems to be fine. Both pickups are working, and the tone and volume knob do what they're supposed to. However, when I am not touching any metal on the guitar, it buzzes noticeably. If I touch the bridge, knob, strings, etc. the buzzing stops. Do any of you know what might be causing this to happen?

Sounds like your bridge isn't properly grounded, check that first.
 
Roland said:
Ok yeah I thought that might be the case. It doesn't matter, I'm fine with the 60 cycle hum because I love the tone of the pickups. For future reference though, what do you find to be the best material to shield control cavities/pickguards/etc. with?

Nothing. Air. I don't put shielding in pickup or control cavities. It doesn't hurt anything, but it doesn't do any good, either. The only people who shield pickup and control cavities are do-it-yourselfers and some "boutique" builders.

It is sometimes helpful to put a piece of aluminum or copper sheeting under the pickguard if you use one, to prevent static build up. But, that doesn't eliminate any hum, it just prevents that crackly noise you sometimes hear on plastic pickguard equipped guitars.

For hum, the thing to do is use shielded cable, and keep any unshielded wires as short as possible.
 
jackthehack said:
Sounds like your bridge isn't properly grounded, check that first.

If his bridge wasn't grounded, touching it would have no effect. If the polarity of the line running to the bridge or trem claw was backward, touching it would make the noise louder.
 
Cagey said:
jackthehack said:
Sounds like your bridge isn't properly grounded, check that first.

If his bridge wasn't grounded, touching it would have no effect. If the polarity of the line running to the bridge or trem claw was backward, touching it would make the noise louder.

You're clueless and that makes no sense at all...
 
jackthehack said:
You're clueless and that makes no sense at all...

Whether or not something makes sense to you has no effect on the laws of physics. But, just for fun, if the bridge isn't grounded, where you suppose the signal goes when he touches it? Atlantis? Buffalo?
 
jackthehack said:
Cagey said:
jackthehack said:
Sounds like your bridge isn't properly grounded, check that first.

If his bridge wasn't grounded, touching it would have no effect. If the polarity of the line running to the bridge or trem claw was backward, touching it would make the noise louder.

You're clueless and that makes no sense at all...

Actually, Cagey makes perfect sense.  It's your body that's noisy and it's getting picked up into the 'hot' lead.  If the bridge ground was connected to said hot lead, it would get very loud - much like touching the tip of a guitar cord plugged into an amp. 

The whole idea of grounding the bridge is to give all that noise your body is picking up a path to ground so it won't get into your signal path.  If you don't like grounding your bridge, you can just ground yourself some other way.  That aluminum toilet seat is good for something after all!  :)
 
Roland said:
Hey I just finished wiring up my Warmoth, and electronically everything seems to be fine.
Both pickups are working, and the tone and volume knob do what they're supposed to.
However, when I am not touching any metal on the guitar, it buzzes noticeably.
If I touch the bridge, knob, strings, etc. the buzzing stops.
Do any of you know what might be causing this to happen?
This kind-of just happened to me too.  :doh:
Slightly different thou ....
It's when I touched the switch or switch screws !!!
Is when I get a buzzing / hum effect.
 
Without neck or strings on .....
Was testing controls / pups etc, all good.
Except ONLY when I touched the switch (chrome tip) or the 2 mount screws holding the switch.
Interference was there.

Pots (with plastic knobs) and the Chrome hum rings and screws all good (NO buzz or hum)

I know I know I know ... I don't use the shielded wire for hot out  ...... Cagey  :icon_biggrin:

:icon_scratch:  Then thought of trying something.
Squeezed a wire between the switch and ran it to an earth and soldered it.
(It's a strat 3 way switch that don't have a earth like a LP toggle switches)

Now there is NO hum or buzz when I touch the switch or the screws holding it.
:dontknow: ....  if thats what you do ..... but it worked  :icon_thumright:

.... Man this purple strat is giving me a hard time  :tard:

Can see in pic, where I squeezed the wire into the bottom of the switch.

539ba536.jpg
 
You have too much exposed signal line. The effectiveness of  shielded cable is dramatically reduced if you strip half the shield off. Also, you need to shield the line out.
 
:doh:  Ok thanks
More digging around, great .....

Funny it got rid of it thou  :icon_scratch:
 
Grounding that switch housing kept it from behaving as a radiator the same way the OP touching some piece of grounded hardware kept his body from being a radiator.
 
Don't forget you only need to ground the shielding at one end. At the other end you can just strip straight to the inner insulator. Typically it's easier to ground at one end, for instance if one end goes to a pot.

Also it's better to pull the inner core out through some shielding and connect it, and then take the shield to a ground point, than it is to strip back loads of shield near a ground point and run the signal from there.
 
I know what Cagey is saying.
But you lost me there Jumble.  :icon_scratch:

Anyway ...
I don't have shielding cable from the mid / vol lug to output.
I usually don't. But I really know I should start using it.
That is PROBABLY my issue.  :doh:

I'm using grounding lugs on the pots, have a earth from one to the other then to output jack.
Vol pot lug is earthed to one as too is the cap.
Have a earth wire coming from one of those earth lugs, to attach pup earth wires.
Which is what I usually do.

Custom 5 in the bridge (4 conductor) and a 59' in the neck, But it's a (2 conductor) thats the braided wire.
1st time I've mixed 2 & 4 conductor, but they should work together.
Red & White solider & taped together on the Custom 5.
Green & Bare to earth, with the braided from 59' to the same earth.
Black from both pups to the correct switch lugs neck / bridge.

Now all is quiet ie: no buzz or hum touching any screws switch etc ……
Thats after my botch wire from the switch. (which I still can't work out why)  :dontknow:

But the vol of the 59'  isn't very loud at all, the custom 5 is all good thou.
That's just testing by holding another guitar over the top of the pups.
I'm not stringing up when I know something isn't right yet.
I'll just have to re-do / re-check it all, I think.  :doh:  ... Oh well something to do.

Darn Purple Strat has got something against me, really giving me a hard time.
This happened to me once before I did a simple basic build  :tard:
When I do something with more detail ie: GK-3 internal install, all goes well.  :laughing7:
Gotta buy some shielding wire and a new meter !!

1st the Sperzel Tuners stuffed up ...
2nd Graph Tech Saddles stuffed up .... getting RMA on them.

This Purple strat is now banished to the naughty corner, for a few days  :icon_biggrin:
I think it's bloody jinxed .....
 
Updown said:
This Purple strat is now banished to the naughty corner, for a few days  :icon_biggrin:
I think it's bloody jinxed .....
It kept looking at me  :evil4:  So .....


:blob7:  Yippie Yar Yar .....  I Fixed it !!  :icon_biggrin:

Pulled out the 2 conductor 59' from the neck (it just wasn't loud enough) had about 1/10th of the vol of the Custom 5
Not sure why  :icon_scratch:
I just knew it shouldn't be that much difference between the two.
Did try re-soldiering etc, but it just didn't work  :dontknow:

Put in a 4 conductor 59' (just happen to be lying around, that I forgot about)  :doh:

Per-fect-o  :headbang: .... and quiet as a mouse.

Now just gotta put the neck on, but before doing that,
I'm taking it to my local music shop guitar tech (5minutes away) to do some smoothing of the fret ends etc.
The best part about this, is he's gunna show me how this is done  :icon_thumright:
He also raves on about how good the Warmoth necks are. He's got many.
But of cause, I already knew that  :icon_biggrin:
 
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