Shielding

northwalianbass · #1 05-26-2006, 06:10 AM

Hi there,
I'm building a bass and have just wired in all the pickups and need to know, do i have to shield the control cavity or can i leave it unshielded. Im using EMG pickups and since they are internaly shielded i didnt think i needed to. Just checking though.

Cheers

Sneakyfella · #2 05-26-2006, 10:39 AM

You can never have enough shielding.

Do a search for this topic, you will find just what you are looking for.

Trevorus · #3 05-26-2006, 10:58 AM

Actually, did you know that some serious guitar audiophiles consider shielding to be a hindrance to high frequency signals? They consider shielding near the coils of the pickups possibly a bad idea. Crazy guitarists...

Kenny Allyn · #4 05-26-2006, 11:30 AM

I'm guessing your going to use EMG active pickups? ... I'll just relay this, I had them in my Spector and have since replaced them with passive pickups ... there was NO shielding in the bass (was in the control panel) we had to add shielding for the passives and grounds. I referenced the fine shielding thread on this forum BTW. Anyway if the bass I have is any indication then NO you should not have to do shielding for active EMGs.

Trevorus · #5 05-26-2006, 11:31 AM

IIRC, emgs are internally shielded.

Bob Lee (QSC) · #6 05-26-2006, 04:42 PM

Shielding will help against electrostatic noise fields. Magnetic noise fields are more prevalent, but that's what humbuckers are for.

bigd4207 · #7 05-26-2006, 07:53 PM

Emg actives you do not sheild, passive pickups you do.

Jazzin' · #8 05-26-2006, 07:57 PM

Sorry if this counts as hijacking a thread...
I have a noobish shielding question.
What if I were to just slap some aluminum foil under the pickguard of my MIM Jazzes, would that help even a little bit for shielding? I am a very lazy person as you can tell. Is it worth the 20-30 minutes of work?

bigd4207 · #9 05-26-2006, 08:01 PM

Takes 5 minutes to run a wire from the ground to the bridge. Take the time and do it right.

Jazzin' · #10 05-26-2006, 08:10 PM

Quote:

Originally Posted by bigd4207

Takes 5 minutes to run a wire from the ground to the bridge. Take the time and do it right.

If you are answering my question, I already have a ground wire attached to the bridge.

So would slapping on some aluminum foil be useful?

bigd4207 · #11 05-26-2006, 09:21 PM

I doubt it, once it's grounded its good. It could even interfere with something.

Jazzin' · #12 05-26-2006, 09:41 PM

Quote:

Originally Posted by bigd4207

I doubt it, once it's grounded its good. It could even interfere with something.

But my bass still isn't shielded and still has noise. Grounding only gets rid of certain noise.

Trevorus · #13 05-26-2006, 09:49 PM

Quote:

Originally Posted by bigd4207

Takes 5 minutes to run a wire from the ground to the bridge. Take the time and do it right.

If you are using active pickups like EMG's you do not want to connect the bridge ground. Passive, you can even get away with not having it. The reason is possible interaction of ground loops. The best way I have found to quiet a passive bass is star grounding. Electrically it looks the same, but in practice it works wonderfully.

Nick Ioannucci · #14 05-26-2006, 10:39 PM

aluminum foil... idk man if it bothers you that much why dont you do it right? noise has been bothering me so i had my dad order me this great 3M 2" wide copper adhesive tape from work. i cant wait to see how much itll help with noise and such.

bigd4207 · #15 05-27-2006, 12:38 AM

Quote:

Originally Posted by Trevorus

If you are using active pickups like EMG's you do not want to connect the bridge ground. Passive, you can even get away with not having it. The reason is possible interaction of ground loops. The best way I have found to quiet a passive bass is star grounding. Electrically it looks the same, but in practice it works wonderfully.

As I stated above, active emg's you do not ground, what exactly is star grounding? Never heard of it. And by the way jazzin, if you want to help sheild try brass mesh instead. That helps keep out any unwanted frequencies. All metals are not created equally, some help some hurt.

Trevorus · #16 05-27-2006, 12:43 AM

star grounding: all ground traces come to one central point. If you use a shield of some sort, make sure you supply only one path to ground. I would generally make the shield unable to connect to the pots any other way than through the star ground pattern. I built a guitar with just star grounding (no shielding), and it was the quiteset I have ever heard.

Sneakyfella · #17 05-27-2006, 09:59 AM

Call me a fanatc, but if I could.... I would shield the world.

RyreInc · #18 05-27-2006, 11:41 PM

Quote:

Originally Posted by Sneakyfella

Call me a fanatc, but if I could.... I would shield the world.

How would birds migrate? Huh?!?

Bob Lee (QSC) · #19 05-30-2006, 10:46 AM

Quote:

Originally Posted by Nick Ioannucci

aluminum foil... idk man if it bothers you that much why dont you do it right? noise has been bothering me so i had my dad order me this great 3M 2" wide copper adhesive tape from work. i cant wait to see how much itll help with noise and such.

Copper adhesive tape is popular for cavity shielding, and it works pretty well as long as you ground it.

lilboo77 · #20 05-30-2006, 10:57 AM

Quote:

Originally Posted by Bob Lee (QSC)

Copper adhesive tape is popular for cavity shielding, and it works pretty well as long as you ground it.

They make copper foil - sold on rolls same as aluminium foil, but it is copper and usually a little thicker - you should be able to find it at most craft stores along with some 3m spray adhesive and you should be good to go.

I have used aluminium foil on the back of pickguards and control cavity covers with good results, but I didn't shield the cavity - just did a star ground and put shielding on all the outside stuff.