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Any experience with shielding your pickups?

Posted: Mon Sep 03, 2007 6:59 am
by bassman2k
Rickenbackers are probably the noisiest basses made. At least from what I've played. I'm looking into shielding the electronics with copper tape. Does anyone have experience and/or have tips on how to do this and how it worked out?

Posted: Mon Sep 03, 2007 10:09 am
by ajish4
There have been many posts from John Hall about this on both forums.

I presently have a 4003 at my luthiers having this very thing done. The control cavity, pickguard AND the pickup cavities are being shielded with copper tape.

There can be MANY external causes for this to happen. It can run the gambit from faulty house wiring, dimmer switches and Fluorescent Lighting all can cause noise problems. ALSO, I've heard mention of switched polarity and improperly grounded outlets are all contributors to noise.

The problems I'm having are definitely externally caused. My bass is like an antenna. I point it in one direction and it is dead quiet, I point the bass in a different direction, and the noise makes me crazy.

My luthier referred to it as Faraday's Cage.

http://en.wikipedia.org/wiki/Faraday_cage

He couldn't guarantee me that it would work, he explained the difference between 60 Cycle hum (that all single coil pickups have) and external noise, which is what I am having a problem with. BUT, I'll let you know how I make out when I get it back next week.

Posted: Mon Sep 03, 2007 10:34 am
by rictified
I did two once with copper tape. I was running stereo at the time and picking up everything within ten miles of me. After I shielded everything and I mean everything it was quiet as a churchmouse. I did the complete pickguard, the bridge pickup cavity, and the whole control cavity up to and including the neck pickup cavity. I made sure they were all soldiered to each other (the pieces) with wire and that the top piece on the pickguard grounded out to the bottom piece. The whole thing was grounded to the ground on the output jack. If everything isn't grounded whatever isn't will act like an antenna and be even more noisy that it was originally. The difference was dramatic, I had to aim the bass at neon lights to get any buzz at all.
If it is done right it will be very quiet, if not it will be worse than it was before.

Posted: Mon Sep 03, 2007 12:18 pm
by jwr2
Ric's are not the noisiest ... a jazz bass with one volume turned down is really noisy ... the noisiest basses are the ones with single coil pickups and active electronics ...

also I have tried to shield Ric basses with copper foil, aluminum foil, the black shielding paint, and they all still sounded like a bass with single coil pickups ...

I have found 2 ways to quiet down a Ric bass ...

1 - a noise gate
2 - put a jazz pickup in the mute cavity

Posted: Mon Sep 03, 2007 12:27 pm
by rictified
"the noisiest basses are the ones with single coil pickups and active electronics ..."
I agree with this, but when properly shielded a Ric can be very quiet.

Posted: Mon Sep 03, 2007 12:50 pm
by gray
My 4003 can buzz like a beehive in some places, but they're all chock full of beer signs and giant TVs. One place, I have to play right under the giant TV, which drives me nuts, because the other side is just a wall of beer signs.
But some other places, you can't even tell when the amp is on, it's so quiet. At home it barely makes a peep until I play it.
So in the end, even though I've considered shielding, I've just chosen to let it go. In the end, the less time we take between songs, the less anyone notices buzz anyhow. The easiest cure seems a mute pedal.

Posted: Tue Sep 04, 2007 12:39 pm
by rictified
I could take those two 4001's into the worst noisy environments and they were always quiet unless I deliberately aimed it at something I knew would make it buzz. Good shielding works wonders, your sound is cleaner too.

Posted: Tue Sep 04, 2007 12:49 pm
by johnhall
Bob, you're very lucky to have hit the winning combination on the first try. Usually this mass shielding method creates so many ground loops that the noise level increases rather than decreases. It's really a black art to determine where those drain wires should go and what bits should be part of the scheme.

I guess what I'm saying is that not everyone is going to achieve the results you did, working only from your description. Close-up pictures, on the other hand, could be quite useful.

Posted: Tue Sep 04, 2007 12:57 pm
by bassman2k
So what is the best way for shielding (if there is one) or reducing noise in general? I have a noise gate, but it's one that activates when I'm not playing. When I am playing, I hear the noise. Besides, it takes away from my tone, and I'd prefer to not use it if possible.

Posted: Tue Sep 04, 2007 2:19 pm
by jps
Another solution would be the Alembic way, by using a dummy coil hidden under the pickguard to make everything humbucking.

Posted: Tue Sep 04, 2007 3:30 pm
by rictified
All I did John was to soldier wires from piece to piece, to make it all one solid piece of conductive copper. I only hooked it to ground at one place: the ground side of the mono jack I believe. So I don't think there were any ground loops in there it wasn't just a random thing, I was careful. I did lay the tape and overlap, I just didn't trust the connections with adhesive sticking to copper so I soldiered them just to make sure. It was like one big encapsulated shield. This was about 15 years ago and the basses unfortunately are long gone. I'm a Ham too John and know something about ground loops, every piece of equipment in my shack goes to the same ground rod.

Posted: Tue Sep 04, 2007 4:18 pm
by johnallg
What I think Bob did right was let the copper in the cavities lay over on the body a little, then the shielding on the back side of the pickguard can touch the cavity overlay, and a complete "box" is made with the electronics inside. Also do the overlap around the treble pup's surround. Soldering the copper foils together helps complete that "box".

I used aluminum duct tape as that was all I had, but made sure all points measured zero ohms to the jack ground, also doing the overlaps as above, and I too have a dead quiet 4003 - unless I point it at a noise source. It is possible to achieve, but takes understanding the above (and Bob's post) and making it happen. Ohm it all to ground to insure you've got total grounding/continuity.

Posted: Tue Sep 04, 2007 4:22 pm
by johnallg
Forgot the pic:

Image

Put the shielding tape on the inside of the pickguard also to reach the overlapped shielding of the body.

Posted: Tue Sep 04, 2007 4:22 pm
by johnallg
double post

Posted: Tue Sep 04, 2007 11:36 pm
by rictified
Yup that's just about what my looked like, and when you put the pick guard back on it completed the circuit. I had a black trim bass that had so much paint (or whatever it was) on the tailpiece that the allen screws from the bridge weren't making contact with the tailpiece itself which is the way it grounds. The effect was the strings and keys were like a big antenna, very noisy. I cleaned out the holes where the allen screws rested and it became much quieter. The tailpiece is grounded from a ground wire coming from the control compartment, it is not in John's picture.