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applying copper tape directly to a humbucker?
Old 30th July 2020
  #1
applying copper tape directly to a humbucker?

this is kind of a theoretical question, but after shielding my cavities and single coils, i read this article about shielding humbuckers with copper tape and a cover. and i guess my question is this:

if the tape is not in contact with the magnets or solder lugs, and is grounded, what purpose does the cover actually serve? potentially a stupid question. as the article explains, you want to make an H pattern of tape on the inside of a wooden or plastic cover. why wouldn't you just apply that pattern directly to the plastic? i've had trouble with microphonic covers in the past, and the H-style pickup covers i've seen for sale seems like they have potential to vibrate, just resting on top of the humbucker.

admittedly i'm a terrible student of electricity, just trying to understand the situation. tape seems like the simplest way to do this to me. my rehearsal space has a ton of noise in it and i'm going to be micing the amps and doing a record in there shortly. i have ebtech hum-x installed, there's no ground loop.
Old 30th July 2020
  #2
Gear Guru
 
Muser's Avatar
I think what he’s saying is to do with replacing the metal shielding cover in a hum bucker. the Filter’Tron geometry is used as an an example to copy. but you use a plastic cover and line it with copper tape and copy the geometry of the Filter’Tron. because he’s claiming this design breaks up the eddy currents which a full metal humbucker housing produces in the way it alters the magnetic field.

presumably the housing is to soak up external electrical interference, then the metal converts it to a voltage and it’s allowed to run to ground.
Old 30th July 2020
  #3
Lives for gear
 

I did this to a vintage PAF humbucker set. --- uhhh about 35 - 40 years ago. They're still going strong though. To Tell the truth, I'm afraid to try and remove the tape and copper at this stage. They have a nice green patina to them
Old 30th July 2020
  #4
Quote:
Originally Posted by RBHan View Post
I did this to a vintage PAF humbucker set. --- uhhh about 35 - 40 years ago. They're still going strong though. To Tell the truth, I'm afraid to try and remove the tape and copper at this stage. They have a nice green patina to them
post pics! does it help? any drawbacks?
Old 30th July 2020
  #5
There are humbucking pickup covers with an open top. Those will shield a good amount of buzz while letting all the string vibration through. Line the top with thin copper foil and all the noise is gone with 99% of the sound intact. Use the normal full covers and some top end is lost.
Old 30th July 2020
  #6
Quote:
Originally Posted by Jim Williams View Post
There are humbucking pickup covers with an open top. Those will shield a good amount of buzz while letting all the string vibration through. Line the top with thin copper foil and all the noise is gone with 99% of the sound intact. Use the normal full covers and some top end is lost.
yes i realize that, the question is what purpose does the cover serve if it's the copper tape that does the work? do those h-style ones vibrate and whine like solid ones do? i really don't want to apply resin or solder the thing together, seems like a hassle for a piece that i'm dubious about the value of.
Old 30th July 2020
  #7
Gear Head
 
Glue2020's Avatar
 

Quote:
presumably the housing is to soak up external electrical interference, then the metal converts it to a voltage and it’s allowed to run to ground.
From my understanding the copper foil serves as an electrostatic shield - not a magnetic one . Any currents in that shield should run to ground.
Old 31st July 2020
  #8
Quote:
Originally Posted by hedgehognrown View Post
yes i realize that, the question is what purpose does the cover serve if it's the copper tape that does the work? do those h-style ones vibrate and whine like solid ones do? i really don't want to apply resin or solder the thing together, seems like a hassle for a piece that i'm dubious about the value of.
Aahhh, just wear your mask!

But seriously, surrounding ther pickup with conductive metal creates a Faraday cage around it to block electronic noise.

And if your cover "vibrates and whines" somethings's probably wrong - somebody has installed the cover improperly. A metal cover on a humbucker should have the cover soldered to the baseplate at two points, one on each side of the bottom of the pickup.

If it isn't soldered it may not be making proper contact to shield the pickup.
Old 31st July 2020
  #9
Quote:
Originally Posted by John Eppstein View Post
Aahhh, just wear your mask!

But seriously, surrounding ther pickup with conductive metal creates a Faraday cage around it to block electronic noise.

And if your cover "vibrates and whines" somethings's probably wrong - somebody has installed the cover improperly. A metal cover on a humbucker should have the cover soldered to the baseplate at two points, one on each side of the bottom of the pickup.

If it isn't soldered it may not be making proper contact to shield the pickup.
it's in contact with the faraday cage i made out of the entire cavity, does that count?
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Old 1st August 2020
  #10
Quote:
Originally Posted by hedgehognrown View Post
it's in contact with the faraday cage i made out of the entire cavity, does that count?
It really needs a soldered connection. Else you can have an intermittent, which can cause intermittent noise problems that can be hard to locate.
Old 1st August 2020
  #11
Quote:
Originally Posted by hedgehognrown View Post
it's in contact with the faraday cage i made out of the entire cavity, does that count?
Judging by those photos, you need to take it to a tech or luthier who actually knows what he's doing. Because whoever did that CLEARLY does not.
Old 1st August 2020
  #12
Quote:
Originally Posted by John Eppstein View Post
Judging by those photos, you need to take it to a tech or luthier who actually knows what he's doing. Because whoever did that CLEARLY does not.
yeah but he had fun applying removable copper tape to a couple of broken spare parts to try and give someone a visual. it's not like i asked if it's ok to check your tube amp caps with both hands while it's plugged in. i'll ask this in the simplest way i know how.

what is the difference between this:



(and we're assuming here that the copper in connected to a shielded cavity, and that the windings and magnets have been wrapped in pickup tape and/or electrical tape before the copper was applied)

and this:



and this:





and this:



and i'm not looking for feedback about the execution, i'm trying to understand this from a theoretical perpective.
Old 1st August 2020
  #13
Quote:
Originally Posted by hedgehognrown View Post
yeah but he had fun applying removable copper tape to a couple of broken spare parts to try and give someone a visual. it's not like i asked if it's ok to check your tube amp caps with both hands while it's plugged in. i'll ask this in the simplest way i know how.

what is the difference between this:



(and we're assuming here that the copper in connected to a shielded cavity, and that the windings and magnets have been wrapped in pickup tape and/or electrical tape before the copper was applied)

and this:



and this:





and this:



and i'm not looking for feedback about the execution, i'm trying to understand this from a theoretical perpective.
The "execution" has a lot to do with how well the shielding works.

Shielding tape on the top of the pickup does little, if anything. OTOH it probably doesn't hurt.

Shielding of a pickup MUST be connected to a ground wire or it won't work.

Pickup covers do supply shielding, unless they are plastic. This includes "chrome" colored plastic.

Not all metals shield equally.
Old 1st August 2020
  #14
Quote:
Originally Posted by John Eppstein View Post
The "execution" has a lot to do with how well the shielding works.
i don't even know if i want to actually do any of these things to an actual functioning guitar yet, i'm trying to get a very simple question answered.
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