string grounding question

[thelloydr]

hi all,
this is probably a stupid question but thats exactly the sort of question i get stumped on. I know very little about electronics and when wiring up components i just follow the diagram and hope it works...anyhow-
when I wire up my guitars, I run the string ground wire from underneath a bridge-post (tune-o-matic) and join it clumsily to the humbucker's metal cover via the humbucker screw. Would it make any difference if I just fed the string ground to my star grounding point? how does everyone else do it? String grounds only get a passing mention in hiscock's book...
cheers,
thelloydr

[mongrel]

Hey,
listen, grounding seems to stump a lot of people, just one of those things I guess. "grounding" is a horrible word cause there is no "ground" per se. Like people saying that the negative on a car is "earth" or "ground" when it sits ISOLATED from the ground on 4 rubber tyres.
OK
There are two lines in all electrical work, source and sink. AC or DC it doesn't matter - in the most fundamental way - you have power comming from somewhere and somewhere for it to go.
The "ground" is the sink, the place the power needs to go.
Power follows the path of least resistance so we surround a signal - the "source" with a "ground" which is essentially 0 volts This acts as a "sink" or a "drain" to any extronious signals floating around outside the guitar, 50 hertz hum from flouro lights, mobile phones, unshielded electrical items etc get attracted to and neutralised by the "ground".
So the thing is the more comprehensive your "grounding" network is the better.
If it doesn't carry a signal then ground it. If it's got a metal case like pots and some switches then 99 times out of 100 you should ground it. You can tell if it shouldn't be grounded cause most times you lose signal completely if you ground a signal line. hell I ground truss rods when I can. If you cant solder it then pressure connect it with a screw or a bold. If its insulative paint then put a self tapper in first with your wire on it and paint over it.
Because the guitar is usually not connected to the ground physically the ground is connected to your amplifier by your guitar lead, so make sure your common connection to the jack is secure and well soldered.

Look, I am no teacher and it is hard to describe this sort of thing without pics, so if enough people want it I could put a tut together if you want. I am trades qualified in electronics and with a bit of time I think I could put something together that would explain it much better than this.
All shielding work I do has a common point that I work back to, guitars are the same. It puts more wire in your axe but each wite is a potenital noise sink and that seems good to me.

Cheers

Jason

[black_labb]

the strings are actually grounded when the amp is grounded. the ground on the guitar is connected to the amp chasis, which is grounded*. it doesnt usually seem that way, as you thing of it as the second part of the signal, but it is there. extra hot/ signal wires will give you more hum, but anything attached to the ground shouldnt give you any hum.

*some vintage/old amps are not grounded, but the reissues are.

[thelloydr]

thanks guys,
I guess i'll just ground it to the star point and see what happens. btw all my negative leads, pot cases etc always go to this point, no loops as in grounding a -ve pot connection by bending it back onto the case. last guitar I made was pretty much totally noiseless, thanks to the star grounding and judicious use of copper foil tape. I just see the lead from the bridge post to the metal pickup cover as difficult to secure, I have had the connections come loose before with this arrangement. It would be great to see a tutorial on this stuff somewhere, its something I know I havent thought about since high school (physics) and like many people i got a bit rusty on it.
lloydr