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Is this a shielding issue?

#21
I have now shielded 8 basses successfully. I'm a very happy bassist these days, I feel like I have discovered a new instrument! I use 3 coats of Stew-Mac shielding paint for the control cavity and the pickup cavities. I use copper foil tape bought on E-bay for the pickup covers and the underside of the pick guard. Although my multimeter does not read "0" I still don't hear any of the old buzzing that I used to. The paint is very easy to use and easy to clean up. I'll easily be able to shield 10 basses with one can. So even though the paint is expensive for a small can, it works out to about $3.50 total in paint and copper foil. The paint is way faster than the tape, and is easier to use, and cleans up very easily. Q-tips for paint application in the wire chambers between cavities.

And you OCD perfectionists will cringe, but I did all this without disconnecting any pickups or wires, other than to unscrew the ground lugs. So yes, I painted the the wire tunnel to the main control cavity, using a q-tip to apply the paint, while the wires were still in the tunnel. Yeah, it got a little sloppy, but in the end it did not matter, because the only thing that did matter was coating the wood tunnel.
 
#22
Eight more silent basses? I love it!

I would just find it more irritating with the stuff in the way than be worried about getting paint on some wires. I usually just pull the ground wire from the bridge and pull the guts as one piece. I also spray my paint, I do not brush it on. I would be worried about getting paint on the body. If you do not immediately remove conductive paint, you will never remove it.

Personally, I have never bothered with wire cavities. My basses are as silent as they are going to get so I don't waste the effort. You will also never read 0 on the mulit-meter, it only hits 0 in theory (I think.)
 
#23
Interesting about not shielding the wire tunnel... And I hear what you are saying about getting in the way, but I still find it's easier than re-soldering lead wires (J basses). Not sure what you mean about paint clean up. A wet paper towel, or at most a dab if gum-off, is all it takes. And saves lots of time not having to tape an entire bass. But to each his own... If it works, it works!
 
#24
I use copper for everything, but for those who like paint, I recommend the same Q-tip trick you use to shield the wire channel. I never thought of doing it with the wires in it, but there's no reason not to as long as the integrity of the insulation is sound (and if it's not, it's an issue that needs to be addressed anyway, and coating the wires with shielding paint could actually help troubleshoot it quicker). Even for those who use a spray, a two or three second shot on a newspaper should provide enough paint to Q-tip the wire channel.

It's certainly less risky than replacing unshielded pickup wires with shielded wires. And it's so easy to do, not doing it because it's a "waste of effort" is a silly reason not to do it.
 
#25
I'm going to test this theory further in the near future, but it is starting to seem to me that shielding the interior of the plastic pickup covers may be overkill. I say this because I had to trim some of the shielding tape in 2 of the P-basses I recently shielded due to contact between my copper tape and the hot wire in the pickup, which was leading to problems in the pickup signal. While I had the covers off, I decided to plug the bass in with the pickups in place but not screwed down, and without the covers on. I had the bass otherwise assembled fully. I noticed no real difference in audible noise, the bass was just as quiet as it was when the covers were on. Interesting... Especially when considering the time and effort involved in shielding the plastic pieces with little strips of copper tape, and when considering the contact issue with the pickup hot wire, which I can tell is something I'll have to do a better job accounting for in the future.
 
#26
bassman_al said:
I'm going to test this theory further in the near future, but it is starting to seem to me that shielding the interior of the plastic pickup covers may be overkill. I say this because I had to trim some of the shielding tape in 2 of the P-basses I recently shielded due to contact between my copper tape and the hot wire in the pickup, which was leading to problems in the pickup signal. While I had the covers off, I decided to plug the bass in with the pickups in place but not screwed down, and without the covers on. I had the bass otherwise assembled fully. I noticed no real difference in audible noise, the bass was just as quiet as it was when the covers were on. Interesting... Especially when considering the time and effort involved in shielding the plastic pieces with little strips of copper tape, and when considering the contact issue with the pickup hot wire, which I can tell is something I'll have to do a better job accounting for in the future.
Click to expand...

I also gave up on shielding INSIDE of the pickup covers. I eventually settled on just shielding the pickup routs and the wire tunnels. Not only is shielding the inside of pickup covers a hassle, and ti can lead to shorts, but also I found that having the shield so close to the coil adds a lot of capacitance which can change the tone. And like you I never found the internal shielding to work any better than just coating the pickup cavity.

On the other hand one internal shielding I DID find important is grounding the pole pieces. This can be done with a strip of copper:
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If you don't ground the poles they can inject noise right into the coil! My personal choice for pole grounding is a Radio Shack conductive pen. You just draw with the conductive ink on the poles and run a line of the "ink" over to the ground connection. Same idea as the copper but done with conductive paint. Note that the other Audere FAQ on shielding shows the inside of the pickup cover lined with copper which I gave up on doing for the reasons above.
 
#28
Interesting and definitely useful! I think I will try the copper tape solution as I'm not following how you would run a line of ink to the cavity ground or output jack ground, other than to slap a grounded piece of copper tape over the conductive ink, in which case it would be just as easy to run tape over the entire bottom of the poles...

I'm excited to think about how nice it would be to play a P bass (or J) without having to ever worry about the opping noise that happens when I accidentally touch the poles on the top of the pickup!
 
#29
Due to a short I removed all tape from pickups in one P bass. No audible difference. Then discovered short was in jack due to hot wire touching cavity wall. Covered hot wire and back of jack contact with electrical tape. Fixed. Any other ideas for more pro-looking fix to covering exposed hot connections?
 
#31
ex-tension said:
Any info about the 'life' of that ink? For how many years it will stay conductive?
Click to expand...

It's called a "circuit writer pen (Radio Shack 2760037). The paint has powdered silver in it and I figured if it doesn't last forever it least should last as long as the conductive glue on the copper foil. The pen has this sort of valve thing on the tip (you push down to write and release paint) that seems to make the pen keep from drying out even when store a while after using it. It was especially useful on my G&L MFD pickups where it's hard to reach the poles to ground them.
 
#32
I'm not saying not to use the pen as it sounds like a handy tool, but the adhesive backing on the copper tape is good stuff. I'm not sure where the idea came from that the adhesive will dry out or become ineffective but I'm certain it wasn't from personal experience of having properly installed shielding on a bass come loose. (The adhesive on duct tape outlasts the tape itself -- if copper tape wasn't copper, I'd be tempted to say the same thing about it. IME.)

I'm also not saying you said that, but your post kinda hinted at it.
 

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