Conference napalm::guitar

    You can buy copper foil (look in the stained glass shops if you can't
    find it anywhere else). This stuff will usually handle sheilding
    problems quite well. There is a paint (I think that both Stewart
    McDonalds and Luthiers Mercantile sell it) that you can apply. I
    prefer the copper shield & build it into the guitars that I make.
    An aluminum pick guard may help quite a bit too, but, I personally
    like the look of the plastic guard. I doubt that the pots are the cause
    are the specific problem, however I believe that is all of the
    unshielded wiring that you need to consider. Go for the copper (it's
    really quite thin & can be cut & shaped with scissors), and glue (with
    epoxy) the cut and soldered together sheild in place.

							    Jens

    Stewart MCdonalds sells conductive paint for shielding the cavity.
    
    anybody ever use it?
    
    dbii

    Hmmmm... this is an interesting discussion, in that, I have noticed
    a little crackling (static) throught my amp when I touch the strings
    (sometimes) and also a hum that goes away when I put my fingers
    in the strings.... I just assumed that I had an open ground in my
    wall socket.  Could these problems be corrected with shielding?
     Wouldn't Aluminium foil work as well??

> a hum that goes away when I put my fingers in the strings
> I just assumed that I had an open ground in my wall socket.  

That's exactly what was happeing to me, and I made the same assumption
at first. But when it also occurred in the music store, I knew it
was in the guitar itself.

Alan S.

    
    That hum you are hearing is found in almost all guitars.  I have
    never had one that *didn't* do it to some extent, although some
    were *much* noisier than others.  
    
    Being around fluorescents and improper grounding tends to worsen
    the problem, shielding and preamps tend to help it.
    
    

    Yep, mine does all of the above as well.  Sometimes, it's really
    noisy if I've got a radio or a PC on near it. Obviously, humbuckers
    are quieter than singles.  If there is a ground going under the
    bridge, is that indicative that the pots are not shielded?
    Are there other sources of hum that come solely from the guitar?
            
    /c
    

sorry guys but aluminum foil for some reason does not work well as a
    shield and GOOD LUCK SOLDERING IT---IT CANNOT BE DONE!!!stick with
    the copper or the conductive paint-both work very well;as long as
    you're at it,put a small cap in series w/the wire going to the bridge
    to cut down the level of pain! the ground to the bridgeis to enable
    the strings to help shield the pick-ups and has na-da to do w/the
    pot's shielding-emg's do not require this ground -i dont know why.
    see you all later---bill k.

    Whether aluminum foil will works depends alot on whether the problem
    is caused by electric fields (buzz) or magnetic fields (hum). Either
    way, copper will work, so I vote with -.1.
    
    Danny W.

    Hmmm, don't know if it's buzz or hum, but my SG makes a hell of
    a racket when I switch on any distortion unit whilst I'm using the
    P90 pick-up and not the hum-buck. I can usually get rid of the noise
    by moving around the room or moving the position of the guitar.
    It actually happens on the hum-bucker too but much less. 
    
    I've tried checking/removing grounds from equipment..no luck.
    Someone said in an earlier note that other equipment can cause it,
    well I usually have 2 to 3 PCs on in the room at the same time for
    my studio, could they be the cause? I'll check tonite, but if it's
    still there with them off I'm at a loss. I'll have to find a supplier
    in Toronto for that copper foil.
    
    Any other suggestions?
    
    Ken
    

I've recently acquired a sqier strat with a troubled past - originally I was
just going to hot rod it with pickups and some of those old Guitar Player
switching modifications.  The neck on it was beat, and I figured I wouldn't
feel guilty about violating the integrity of the instrument since it seemed
to be hurting.  Well, $50 of neck work at McDuff's has got the neck to
good shape (not as good as my SG, but g'nuff anyway).

As a first time Strat owner, I was disappointed and surprised at how much
pickup noise there was, specifically when selecting only one pickup at a
time.  So I checked out notes in here for recommendations on shielding
(e.g. 31, 488, 983, 1125, 1238, 1399, 1787).  I could not locate that copper
foil at auto stores - where do you folks get that and what is it *supposed*
to be used for?  And I learned some things I want to share here - with
questions to the well shielded.

It was suggested that the performance of copper vs aluminum may differ
on mag-fields; their performance being equal on E-fields.  I looked into
this, that is, I asked someone who knows more about this stuff than me.
The summary for the guitarist is that the only effective shield against
M-fields is a 'mu-metal' (Greek letter mu) - some sort of alloy with all
sorts of properties, sort of a kryptonite against noise.  It does not
even need to be hooked to electrical ground since that is not the point.
If you are physically near M-fields, e.g., very large transformers,
electric motors, or high-power lines you will have big problems with
copper OR aluminum.  Fortunately, E-fields are the real noise culprits
and copper and aluminum are effective against these.  Of course, keep
you guitar cord away from AC cords anyway.  As far as aluminum
foil vs copper foil - the effectiveness is a function of the sheet
resistance of the foil - lower is better, I dunno which is lower,
I'd bet on copper, depends on the foil, your mileage may vary.

I read that people recommend foil over the conductive paint - *but why*?
Technically, the sheet resistance of foil will be less than that of a
layer of conductive paint, so therefore foil is better.  But methinks
that the paint may be good enough? Any non-recommendations on the paint?
At least with the paint you can easily shield the back of the pickguard
as well as the cavity and get closer to a complete faraday cage.  I wonder
if you could even shield the inside of the plastic cover on the pickup;
if you could get it off without causing damage.
I suspect that the paint is aluminum-based, how thick is the paint shield?
Apparently, you can buy paint that is effective against E and M fields,
though this is specialty stuff.  How about the copper tape from Stew-Mac,
is this stuff substantial enough to really work?  Has anyone tried aluminum
flashing? (possibly a topic for HOMEWORK).

Anyway, I was fired up to shield the strat so I tried aluminum foil instead.
And I'll tell you what - it works real well!  I'm going to keep the original
pickups!  I bet real copper foil would work even better and would be easier
to work with - the aluminum foil rips if you work it too often or too hard,
even folded over into layers.  To ground the shield, I thumbtacked it to
the cavity, and I mechanically hooked a wire onto one of the thumbtacks and
soldered the other end to a common ground point on one of the pots.
Yeah, yeah, yeah, I know.  I'll do it right later . . .

But what I basically concluded, and what I want to say here, is if you
own a Strat, shield it before you do anything about replacing pickups.
In fact, no matter what you play - shield it.  Even if you know you want
to use the stacked humbucker replacements, when you are in there doing the
mods - shield your axe.  The improvement is tremendous - so good that I
plan to shield my SG as soon as I get a chance.  It seldom has noise
problems, and only in real bad situations, but the Strat improvement is so
dramatic . . . you can't go wrong.  I can't believe that manufacturers sell
models for > 1 kilobuck and don't shield it for you :-(.

Well, times being what they are, this leads me to put forth a cliche phrase
or two to drive home my point so to speak.  After all, it is a modern world,
and this is how one spreads the word so here goes . . .



"Practice Safe Sonics - use a shield"





or, to a rap beat . . .



"Shield you axe - from noise attacks"





or . . .



"If its a Strat you wield -  where's your shield?"





or how about . . .



"If you are gonna take out your axe - shield it to the max"





or maybe . . .



"Foil E&M fields - always use a shield"





or appeal to the higher sensibilities (though this one is discriminatory) . . .



"Good boys - are shielded from noise"





oh yeah - this is going nowhere . . . .
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T