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Jazz Bass Hum

#44
johnk_10 said:
there should be a brass plate at the bottom of the cavity and under each pickup with the ground wires connecting them all together, and one wire coming from it soldered to the back of one of the pots.
i use conductive paint (expensive but effective) and others use adhesive backed copper foil to line the cavites. it's best to use a star ground (i.e. a single point of ground to avoid ground loop)s, and the chrome control plate takes care of the ground plane for the pots and jack (i.e. there shouldn't be a wire going from pot to pot to the jack's ground lug.
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Thanks John, the wiring on my AV62 is as it should be so I guess I should give the conductive paint a go. Do I just paint all surfaces of the control cavity or is there more to it? Also are all these conductive paints the same and where would be a good place to try and get some? (I live in the UK) ATB, Bob
 
#46
bob atherton said:
Thanks John, the wiring on my AV62 is as it should be so I guess I should give the conductive paint a go. Do I just paint all surfaces of the control cavity or is there more to it? Also are all these conductive paints the same and where would be a good place to try and get some? (I live in the UK) ATB, Bob
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i use a product by MG chemicals called nickel print or their silver print.

nickel print:
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silver print:
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#51
bob atherton said:
Thanks John, the wiring on my AV62 is as it should be so I guess I should give the conductive paint a go. Do I just paint all surfaces of the control cavity or is there more to it? Also are all these conductive paints the same and where would be a good place to try and get some? (I live in the UK) ATB, Bob
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Conductive paint is simple, easy, and relatively cheap to do, but be aware that sometimes it gives mixed results and that includes the paint that Fender uses at the factory! Sometimes it's great sometimes not. I have no idea why. Copper foil ALWAYS works but is a much bigger pain to install.

And don't forget any shielding MUST be grounded (to the jack outside terminal or to something connected to it). The usual way to ground paint is with a wood screw through the paint with a lock washer with teeth under the head that bites into paint and a wire lug that is run to the ground point. (they make these cool solder lugs that have a built-in lock washer with teeth if you can find one.)
 
#52
i generally don't use the foil because i've seen it peel up years down the road and sometimes can cause a problem in tight control cavities when you don't even have a mm to spare.

IME, fender doesn't shield them all that well, but nickel or silver print (like alembic uses) works perfectly, and i even paint it with a q-tip or a tiny paint brush thru the pickup wiring holes so the wire is shielded from the pickup routes to the control cavity which is something you just can't do with the foil unless you wrap the foil around the wires and ground it which looks messy to me.

i ground it with a screw and star washer and then paint over the screw & bare wire to ensure a good ground.
 
#55
bassbenj said:
Conductive paint is simple, easy, and relatively cheap to do, but be aware that sometimes it gives mixed results and that includes the paint that Fender uses at the factory! Sometimes it's great sometimes not. I have no idea why. Copper foil ALWAYS works but is a much bigger pain to install.
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Yes it is a pain, but it's all I will use. I've tried all the shielding paints out there and just couldn't get the same level of quiet I get with copper tape. It may peel up a bit in 20 years, but it's easily fixed.

I'm a bit psycho about hum, and all my copper-shielded basses are ultra quiet. Of course you can never totally eliminate hum with single-coil pickups, but you can get very close.

And yes, the shielding (all of it) must be connected to ground. In a J bass, I shield all the cavities. Then I solder a lead from the foil in each pickup cavity to the foil in the control cavity, then a lead from the control cavity foil to one of the pots.
 
#57
johnk_10 said:
IME, if someone can't eliminate the hum as much using conductive paint as much as they can with foil, then they're either using the wrong shielding paint, applying it wrong, or not shielding it properly
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I don't understand why you're so critical of people doing things differently than you. To each his own. And I'm certainly not the only one who has found copper tape to be more effective. For instance, see the GuitarNuts shielding tutorials: Invalid Link Removed

My basses are super quiet. It obviously works for me. I happen to prefer cutting the copper tape to applying 3 coats of paint and dealing with dry times. And in my experience, the copper has yielded better performance.

Different strokes, man.
 
#59
If your Jazz Bass Hums, print out a copy of the lyrics and leave them in the bass case with your bass overnight. That should take care of it. :cool:

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