Bridge grounding: pros and cons

[gorjan]

I am looking into grounding and shielding and have read many controversial things about both. some people prefer just adding layers of shielding to your instrument and not solider a bridge ground, others have said that the shielding is not very effective (read it on this forum somewhere).

I am wondering what is your opinion on the topic, and why do you choose to ground the bridge or not?

Gorjan

[DrGonz78]

Ground the bridge as a matter of fact of whatever type of guitar it is... Let's just say that the strings make a connection to the bridge right? Your fingers are grounded to the strings? Right? So, grounding of the bridge is very easy to do... Shield it with your cable... Ground it with every connection that makes any sort of contact to your strings. Anything else is just opinion... Or maybe my opinion is just to create a ground that connects anything conductive throughout the entire system of the guitar. Grounding out the electronics or there of metal/conductive connections throughout the guitar, is a good idea no matter what. Or maybe that is just my opinion...??? Let's see what your amp says.

[gorjan]

Well I have no background or experience in electronics, so I get confused when reading opposite recommendations. My theory is that when the bridge is grounded you touch the strings and it will quieten up the guitar. but the problem would be that now you have the bridge, strings, tuners (and maybe the nut if it is brass or metal) as a part of your circuit. these bare unshielded metal part would love to soak up 50-60hz hum from any source (neon lights, TFT monitors and so forth...). I wanted to hear what you as techs do and recommend to your clients. Which of these two opinions you support and prefer and why?

Gorjan

[Cygnus X1]

I'd love to be able to getting away with not grounding to the bridge.
Tried it several times and have never been able to get away except in active systems.
It's always an issue.

[Jazz P Bass]

There is something creepy about having the strings (via grounded bridge) possibly connected to the mains (through equipment fault).
Here is a nice work around to this issue.
Link: donh safety circuit

[Chuck H]

That circuit assumes your using shielded pickup leads. Very idealistic. And it's great if all things are in place to implement. I will say that ALL MY GUITARS USE SHIELDED PICKUP LEADS AND ARE WIRED THIS WAY!!! But not everyone is willing or able to add a shielded lead to any pickup. There is a capacitor ground dump circuit around, but I was unable to find it. It's probably just a large cap inline with the ground lead. This effectively would isolate the user from DC while still allowing any AC to ground via that user. One thing I can tell you from personal experience is that you DON'T want to get shocked on stage in front of an audience! You might end up with a nick name like "Sizzlin' Chuck" and it wouldn't be because of your playing

[Cygnus X1]

Chuck I guess you're speaking of the braided wire?
I never do anything with that, it just sits there not connected.
Should I attach that to the foil, circuit ground, or the bridge?

[Chuck H]

The braid is the shield for the pickup leads. If your working in something like a strat that is fully shielded it makes little difference. If your working with a paul you need to attach the braid to the cavity foil because the channels in the guitar that the pickup leads are routed through aren't typically shielded.

[Mick Bailey]

There is something creepy about having the strings (via grounded bridge) possibly connected to the mains (through equipment fault).
Here is a nice work around to this issue.
Link: donh safety circuit

I have a Taylor with a 5ma fuse in the string ground circuit (ES system). These are fairly troublesome (+ hugely expensive, and in the guitar I'm working on not user replaceable). I'm going to experiment with this approach instead.

[Mick Bailey]

It works perfectly. I decided on a 47nf cap with parallel 220k resistor - gives roughly 4.7ma current leakage @ 240v/50hz.