Shielding the pickup covers?

[fourstringbliss]

I know that many of you (myself included) have shielded the control cavity and pickup cavities of your Jazz and other basses. Some have even shielded the pickup coils (with good and bad results). What about shielding the plastic pickup shells?

Here's a picture of a pretty complete shielding job:

[Invalid or Expired Link Removed]

Have any of you done this?

I'm buying an SX Jazz bass from my local GC and I like the sound of the pickups, but like all straight single-coil pups they hum. I certainly plan on shielding the control cavity and pickup cavities, and even the back of the pups with copper foil, but what about the inside of the pickup shells? Would that help kill some of the hum?

 

[Floyd Eye]

Highly unlikely.

 

[Bassamatic]

Since the cavity is shielded, covering the sides of the pup cover will have little effect. Maybe a little bit from the top. For me, I find that doing the cavities is really enough.

Don't forget that all the shielding has to be connected to ground to work. Otherwise it has little or no effect.

 

[fourstringbliss]

Since the cavity is shielded, covering the sides of the pup cover will have little effect. Maybe a little bit from the top. For me, I find that doing the cavities is really enough.

Don't forget that all the shielding has to be connected to ground to work. Otherwise it has little or no effect.

I definitley make sure all of my shielding connects to ground. All of my grounds are connected to the same place in the control cavity.

 

[bassbenj]

Have any of you done this?

I'm buying an SX Jazz bass from my local GC and I like the sound of the pickups, but like all straight single-coil pups they hum. I certainly plan on shielding the control cavity and pickup cavities, and even the back of the pups with copper foil, but what about the inside of the pickup shells? Would that help kill some of the hum?

No. In fact in most cases you DO NOT want to do this. The reason is that the added foil inside the cavity foil does not improve the shielding. BUT, when you have foil very close to the pickup coils it forms a capacitor which can dramatically change the tone depending on what you've done.

What you DO want to do (if possible) is to ground the pole pieces of the pickups. If they float they can inject hum into the center of the the coils. The usual fix it to run a strip of conductive glue copper foil down the bottom of the pole pieces. (this is not always possible depending on how pickup is made)

But what you don't know is that there are TWO kinds of hum. There is the usual hum you pickup from power wiring and that is a hum that can be fixed with copper shielding. The true test for power hum would be if the hum goes away or gets less if you touch ground (srings, jack, control plate etc.)

The OTHER kind of hum is single coil hum. Shielding will not affect this kind of hum. The test for it is touching ground and hum level does NOT change but moving bass in to various orientations DOES change the hum level. The only fix for single coil hum is humbucker pickups. Note that when both Jazz pickups are turned to max (or the same volume) they are wired to cancel single coil hum and act like a humbucker. If you go to either neck or bridge hum comes back. The only fix is to install humbucker or "noiseless" pickups like the stacked coil Fenders (which I don't think much of the tone) or say Norstrands (which I don't think much of the COST! )

 

[eastcoasteddie]

Zombie thread revival alert!!!

I was recently thinking about if this had ever been done; not to reduce single coil hum, but to reduce RF interference.

I found an article about it:
Mod Garage: How to Shield Single-Coil Pickup Covers

And prior to this, they shield the pickup itself:
Mod Garage: How to Shield Single-Coil Pickups

Any reason not to try this if done correctly?

 

[PedullaPlayer56]

No. In fact in most cases you DO NOT want to do this. The reason is that the added foil inside the cavity foil does not improve the shielding. BUT, when you have foil very close to the pickup coils it forms a capacitor which can dramatically change the tone depending on what you've done.

What you DO want to do (if possible) is to ground the pole pieces of the pickups. If they float they can inject hum into the center of the the coils. The usual fix it to run a strip of conductive glue copper foil down the bottom of the pole pieces. (this is not always possible depending on how pickup is made)

But what you don't know is that there are TWO kinds of hum. There is the usual hum you pickup from power wiring and that is a hum that can be fixed with copper shielding. The true test for power hum would be if the hum goes away or gets less if you touch ground (srings, jack, control plate etc.)

The OTHER kind of hum is single coil hum. Shielding will not affect this kind of hum. The test for it is touching ground and hum level does NOT change but moving bass in to various orientations DOES change the hum level. The only fix for single coil hum is humbucker pickups. Note that when both Jazz pickups are turned to max (or the same volume) they are wired to cancel single coil hum and act like a humbucker. If you go to either neck or bridge hum comes back. The only fix is to install humbucker or "noiseless" pickups like the stacked coil Fenders (which I don't think much of the tone) or say Norstrands (which I don't think much of the COST! )

So i'm having a very similar issue with my P/J

cavity is shielded well, connected to ground, pickup poles are grounded, i know its the bass, ive done test to rule out the amp or cables or power. it definitely changes the quality of the hum or static-y noise when i move it around my room. noisy in other venues too. strange thing is, the hum doesn't go away when isolating pickups. p pickup all the way down and j is up, noisy, and vice versa. racking my brain trying to figure it out. any help is appreciated, going on tour in a couple weeks with a bigger artist and id love to use this custom bass i got, but im sure the sound engineers would hate me if i showed up with it how it is currently