My ZAPPPPP!!! copper shielding experience.

[Tomis17]

A couple of weeks ago I got my copper shield tape in after 2 weeks of wait. I was really excited about how it's going to eliminate the humming noise from my bass. I un-soldered the pickups & control plate and immediately put the tape around the cavities. When I got done, I re-soldered the pickups back onto the pots and here's the stupid thing I did: I soldered the ground to the copper in the control cavity. I plugged the bass in and ZAPPPPPPPPP!!!!!!!!!! OUCH!!!!!!! I could feel the electricity run through my body. I thought about it for a sec and realized how stupid I was.

 

[amistybleu]

I thought you were supposed to connect all grounds to the copper shielding, IE: Star Grounding?

 

[Tomis17]

I think you are supposed to for the pickups but not in the control cavity. What I did after I got zapped was tie the ground in electrical tape to keep from touching the copper. It works. This was the diagram I used to get myself zapped. Must've done something wrong.

http://www.talkbass.com/forum/showthread.php?t=159191&highlight=shielding

 

[GeoffByrne]

FWIW:

It's my understanding that all the shielding should be grounded. This turns the inside of the control cavity into a Faraday Cage, effectively, cutting out radio interference.

I have several guitars and basses which I have shielded and they are all grounded in various ways to suit the design.

Geoff

 

[ibnzneksrul]

Sounds like a grounding issue with the amp, not the bass.

 

[lemur821]

Yeah, it sounds more like you've just discovered something you really needed to know about your other equipment. A ground loop in your bass (which it sounds like you have created) should be only a sonic problem, unless you've got other equipment trying to kill you.

 

[Rodent]

agreed - you have grounding issues with your and and/or the electrical circuit that your amp is plugged into

your pickup cavity shielding should be connected to your control cavity shielding ... whether or not you connect your bridge to ground is another story ... and the real culprit that allowed the ground problem in your amp to nail you

all the best,

R

 

[4Mal]

agreed - you have grounding issues with your and and/or the electrical circuit that your amp is plugged into

your pickup cavity shielding should be connected to your control cavity shielding ... whether or not you connect your bridge to ground is another story ... and the real culprit that allowed the ground problem in your amp to nail you

all the best,

R

I've been star grounding for a bit and I ground the bridge to the cavity and the cavity to the jack. Haven't gotten zapped yet but Rodent - am I doing something wrong here ?

 

[Tomis17]

Hmmm...that brings up a real curiosity to me. Should I try it again?

Here's what I have: EMG Jazz pickups and harness w/ V9 battery. I grounded the pickups to the battery together and then ground the 3 of them to the copper in the control cavity. Don't know if this makes a difference but I kept the battery in the control cavity also. Does this cause improper electrical movement thorugh the bass?

 

[ibnzneksrul]

Hmmm...that brings up a real curiosity to me. Should I try it again?

Here's what I have: EMG Jazz pickups and harness w/ V9 battery. I grounded the pickups to the battery together and then ground the 3 of them to the copper in the control cavity. Don't know if this makes a difference but I kept the battery in the control cavity also. Does this cause improper electrical movement thorugh the bass?

Forget the bass.

You have a (potentially dangerous) grounding problem upstream from the bass, with either your amp, or the AC circuit it is plugged into. Please tell us about the equipment you are plugging your bass into, and also if it has a three-prong power plug into the AC outlet.

 

[Foamy]

Forget the bass.

You have a (potentially dangerous) grounding problem upstream from the bass, with either your amp, or the AC circuit it is plugged into. Please tell us about the equipment you are plugging your bass into, and also if it has a three-prong power plug into the AC outlet.

...and get an outlet tester from your local WalMart or Lowe's/Home Depot. They are jsut like a buck or two and have little LED's that will show open or missing ground, reversed neutral and hot, and OK. I NEVER EVER plug in unless the circuit passes the tester's test.
In the interim, you can go wireless. But priority one is to get that outlet or amp fixed!!!! Seriously!!!

 

[Rodent]

I've been star grounding for a bit and I ground the bridge to the cavity and the cavity to the jack. Haven't gotten zapped yet but Rodent - am I doing something wrong here ?

there is an ongoing debate about grounding the bridge ... if you have a grounded bridge and your amp (or the house PA you are running direct into, or the mic you sing into) has an electrical issue like ibnzneksrul notes above ... you stand the very real potential of learning first-hand who your Maker is. If you know well the gear and electrical circuits of the places you play at, and you have tested everything to know it's all connected/working properly, then you're probably OK. But on the chance that something goes wrong ...

if you don't ground the bridge you will obviously get a little EMI buzz when your hands are off the strings - but you won't have the potential to get a deadly zap

still ... it's hard to sell a new bass that has an EMI buzz due to a non-grounded bridge, so most companies chase the $$$ and ground the bridge.

I have delivered several basses with a ground lead coming from the bridge that is not connected inside the cavity. On these basses I have clearly labeled the wire end, and also provided a note explaining why I left this lead disconnected. If a client decides to connect the bridge to ground, they have done so at their own risk.


I'm typing this while somewhat distracted by another conversation ... hopefully it makes coherent sense

all the best,

R

 

[DavidMP]

http://www.guitarnuts.com/technical/electrical/safety/index.php

 

[4Mal]

That's an bit Rodent. I need to mulll that over a bit as I would prefer not to be the butt of 'a guy meets Peter at hte Peraly Gates joke' any time soon ...

 

[bgavin]

The Guitar Nuts link posted above talks in detail about the very real danger of getting Makerized, and how to avoid it.

His articles are designed around Strats, but are easily applied to basses.

 

[Rodent]

http://www.guitarnuts.com/technical/electrical/safety/index.php

That's the page referenced by the discussion I mentioned ... I couldn't find my link for it. Definitely a read that should be had by all, and then make an educated/informed decision on the amount of risk you're comfortable with.


I have a few schematics for bridge ground lead modification that claim to offer a voltage reduction should you be shocked ... but I simply don't have the stomach (or the $$$ insurance policy) to take a chance at something outside of accepted grounding practices

all the best,

R

 

[Thunder_Fingers]

Danger? i have the entire cavity of my bass covered in foil and the bridge ground and pickup ground is conected in the cavity. is that dangerous?

 

[Foamy]

Danger? i have the entire cavity of my bass covered in foil and the bridge ground and pickup ground is conected in the cavity. is that dangerous?

Better not be - that's how I did my Strat. Both of my Squiers came shielded with shielding paint, and my Geddy has metal plates in the cavities. The foil should be just fine. I think what we're telling him is that there is some other external (to the bass) grounding problem.

 

[Rodent]

Danger? i have the entire cavity of my bass covered in foil and the bridge ground and pickup ground is conected in the cavity. is that dangerous?

if your amp, PA, and building circuitry are a-OK, there should be no danger ... if there is an electrical issue (faulty grounding and/or wiring) then there could very well be a danger

hence the whole discussion of grounding the bridge as seen on the referenced web link

all the best,

R