Jazz Shielding Pictorial (Big Images Warning)

[rockchalkbass]

Help! So I attempted to shield my AmDeluxe J and seem to have realized the worst case scenario: yes the buzz is now worse. The bass was already wired with ground lugs in both cavities connected to the jack so I didn't touch any wiring, just unscrewed the lugs and tightened them back down after the copper was applied. Any thoughts?

 

[scotch]

Either the shielding is touching a 'hot' (signal) connection or some portion of your shielding isn't grounded properly?

 

[timobee4]

I shielded my both my basses but I wonder about the pickup screws!! Obviously when they in I get continuity between strings through all the shielding to the screws! Is that ok?? Tnx

 

[BlueTalon]

The pickup screws shouldn't matter at all, assuming the pickup cavity is shielded, the pickup screws go through that shielding, and that pickup cavity shield is grounded to the control cavity shielding. That will ground the screws. And since the bridge should also be grounded, and the strings grounded through contact with the bridge, touching the pickup screws should have the same effect as touching the bridge or the strings (minus the bass tones) -- ideally, nothing.

To put it another way, if you have shielding, then the pickup screws are supposed to go through it.

 

[fnordlyone]

just bookmarked! I need to do this; been out in the yard. Soon, insane heat will facilitate inside tinkering and ; you got a nice document…
much thanks,
fnord!

 

[nickdot]

Shouldn't he have used shielded wire on the output jack?

 

[BlueTalon]

You mean shielded wire internally on the bass or a shielded guitar cable? Inside the bass it's not necessary if everything else is shielded. Inserting the 1/4" plug effectively seals off the jack hole, so if the wires inside are not shielded, it doesn't matter as long as the cavity is shielded to the jack.

 

[chienmort]

Was going to say that the shielding is already in place but was beaten to it.


It ain't how low you can go but what you do when you get there!

 

[Vic]

You mean shielded wire internally on the bass or a shielded guitar cable? Inside the bass it's not necessary if everything else is shielded. Inserting the 1/4" plug effectively seals off the jack hole, so if the wires inside are not shielded, it doesn't matter as long as the cavity is shielded to the jack.

Correct. The only time you should consider using shielded cable inside the instrument is when the wire passes through an area that's not already otherwise shielded... such as the channels from the pickup cavities to the control cavity.

 

[BlueTalon]

My personal approach is to shield those wire channels. I'd rather do that than mess with the pickup wires in any way.


For anyone interested, there are several ways to do it. If using shielding paint, just gob a Q-tip with the stuff and slather the inside of the wire channel with it. Give it a few coats, and be sure to check continuity after it dries.

I prefer to use copper. In my avatar bass, three pickups with rear route control cavity means three wire channels. I got some 1/4" copper tubing from a hardware store, cut it to length, filed the inside edge of the cuts, and slid the bits right into place. I used some copper tape to hold them exactly in place, and then soldered them on both ends to the shielded cavity walls.

If that seems like overkill, it is. The job can be just as effectively done by wrapping copper tape around a straw or dowel, adhesive side out, and sliding that through the hole(s). Ideally, there should be about 1/4" - 1/2" sticking out on both ends. Make some slits lengthwise in the bits sticking out, and then fold them back to the cavity sides. The adhesive will hold them in place, making the new addition pretty much permanent. The job could be considered finished at this point, but why stop now? Use a bit more tape to tidy up, and then solder everything.

Now go have a beer.

 

[nickdot]

You mean shielded wire internally on the bass or a shielded guitar cable? Inside the bass it's not necessary if everything else is shielded. Inserting the 1/4" plug effectively seals off the jack hole, so if the wires inside are not shielded, it doesn't matter as long as the cavity is shielded to the jack.

I meant shielded wire. I've been reading "everywhere" and people are always recommending shielded wire for the output jack. Still a little confused with this exact solder points are though; tone pot to output jack?

And I agree with you on shielding the wire channels. I botched a pickup rewire once and it was hell getting it functional again.

 

[Vic]

...people are always recommending shielded wire for the output jack...

Not needed at all in a properly shielded cavity.

 

[nickdot]

Makes sense. Is there a diagram for a standard J bass wiring? (2 volumes and a tone, instead of the blend OP used)

 

[Vic]

Makes sense. Is there a diagram for a standard J bass wiring? (2 volumes and a tone, instead of the blend OP used)

Many. Google is your friend. Take yer pick.

 

[nickdot]

Found one. I guess my confusion was how the ground of the bridge and pickup negative leads connected with the grounding of the pots, but I guess I just have to make sure the pot plate touches the copper activity well? Is that why people have the copper tape coming out of the cavity a bit?

 

[Vic]

...I guess I just have to make sure the pot plate touches the copper activity well? Is that why people have the copper tape coming out of the cavity a bit?

Correct. And usually at a screw hole to insure a solid connection. Some folks even sand off chrome for best electrical connection... like on the bottom of a bridge for the ground wire.

 

[mikeguyfriend]

Is anybody available in the try-state area, or anywhere in the Northeast really to help me out with this? I'd be happy to throw down some $$$. Thanks guys!! PM me if you're available and know whats up with this stuff.

 

[mickeyj4j]

i wish i could do that to my j

but i cant because i have no idea of how to do it properly

maybe someday...

i am in the same boat no experience in this??? it looks fairly easy to achieve and I can apply tape to things, I have done some basic soldered before so will apply the tape, solder the edges and wire the cavities together. will leave the circuit as is and see if it helps my hum issue Extra Hum: - Normal or not.

 

[heavyfunkmachin]

i am in the same boat no experience in this??? it looks fairly easy to achieve and I can apply tape to things, I have done some basic soldered before so will apply the tape, solder the edges and wire the cavities together. will leave the circuit as is and see if it helps my hum issue Extra Hum: - Normal or not.

My post is years old, since then I've become quite confidebt and perform this to all my basses... Go for it!! not that hard

 

[BlueTalon]

i am in the same boat no experience in this??? it looks fairly easy to achieve and I can apply tape to things, I have done some basic soldered before so will apply the tape, solder the edges and wire the cavities together. will leave the circuit as is and see if it helps my hum issue Extra Hum: - Normal or not.

It is simple, but not necessarily easy. You just have to take your time and be meticulous.

Start with this copper tape on ebay. It's from an American source (even if you don't care much about that, it will get to you much quicker than shipping it from China), and it's the least expensive you are going to find anywhere.

When you apply it, use something to press each piece to the surface so the adhesive fully engages. Make sure you press everywhere on each piece. I use the back of my fingernail for much of it, and I use a tool for the corners and hard to reach areas. Use multiple layers -- you'll have enough tape to where you don't feel the need to scrimp. Don't leave any gaps -- that would be like putting a screen door on a submarine. The whole point is to keep the bad stuff out.

I'm assuming you have a Jazz bass, since you're posting in this thread. I recommend also shielding the drilled wire channel -- you can read the last 10-15 pages of this thread for some ideas on that. My opinion is that if you are already going to the trouble to do the job anyway, you might as well take a little more time to make sure your shielding job is bulletproof.

I have the same philosophy for the bridge ground. What I do is make a foundation for the bridge using the copper tape (one layer, no overlap), that covers less area than the bridge, but is big enough to cover the screw holes. I then solder bridge ground wire to that copper where the hole for the ground wire is, and then solder the other end of the wire to the shielded cavity wall.


Two other things not related to shielding. (1) To truly have a noise-free experience on your bass, you should really have hum canceling pickups. All major pickup manufacturers make them. (2) Make sure the electrical outlet you plug your amp into is properly grounded. I went to a guy's house one time, plugged in, and got hum & noise. I thought something was wrong with my gear, but it turned out to be an ungrounded outlet. I ran an extension cord to another outlet that was grounded, problem solved.