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Shielding P-90's in Archtops


charlie brown

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i had a humbucker sized pair in my es333 and they weren't excessively noisy. but i've never tried regular sized p90s, so maybe i don't know what i'm talking about. they were bg pickups pure90s and they are incredible. now i can't turn up too loud because i'm in an apartment, but i used ungodly amounts of gain and some effects and while standing 2 feet from the amp, it wasn't a big deal. i could make it feedback if i wanted to, but for the most part, the noise was contolled to liveable.

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Why, wotcha thinking there Charlie??

 

Surely P90s would "scream" alot more in an archtop (i.e. Freedom of sound via flutes etc) , at least I'd surmise this to be the case (not having an archtop), and to shield them would defeat the purpose of having them installed in the first place No??

 

I would have thought that if you were thinking of doing this then you purchased the wrong guitar surely? I mean we all buy a guitar fit for purpose, i.e. style of music, loudness of music, quality of sound etc so to want to change away from a P90 surely mean that the guitar wasn't right at the time of purchase, maybe I'm wrong, I don't know.. But I have a Goldtop with P90s in it, no comparison to an archtop I know, but the rougher edge they provide I have to say I favour against my other guitars, but its fit for purpose as I play a lot of rock music (70's 80's stuff and it fits ) So I'm curious as to why the change and the reasoning behind it (no disrespect intended)?

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Well, I have a person that does this, down in Edmond, OK., so I know it's possible, and workable.

What I was curious about, is if anyone here, had done that, and how you liked the result?

I'm thinking about doing it on my original '66 Casino, which is quite a bit noisier, than my recently

purchased Riviera P-93 LE. So, that made me even more curious, as to whether or not shielding

would be the way to go, for the Casino. So, that's "Why" I want to do it.

 

I've had a LP with P-90's shielded, and it helped a lot! It did NOT, change the tone,

or "edge/growl" of the pickups, in any way. So, I'm not concerned about that, really. I was just

curious if there was anyone here, that had some expience, with having an archtop shielded?

 

CB

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That's interesting. My understanding is that copper or aluminum foil surrounding the pickup acts as a Faraday cage but I don't understand why the conductive metal base plate or the conductive metal cover that is already on the Casino pickup would not already serve that purpose.

 

Can you explain why an additional copper foil wrap of the bobbin and windings works? I'd probably do it but I would have to unsolder the pickups from the metal covers to do it.

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That's interesting. My understanding is that copper or aluminum foil surrounding the pickup acts as a Faraday cage but I don't understand why the conductive metal base plate or the conductive metal cover that is already on the Casino pickup would not already serve that purpose.

 

Can you explain why an additional copper foil wrap of the bobbin and windings works? I'd probably do it but I would have to unsolder the pickups from the metal covers to do it.

 

A Faraday cage is best understood as an approximation to an ideal hollow conductor. Externally applied electric fields produce forces on the charge carriers (usually electrons) within the conductor' date=' generating a current that rearranges the charges. Once the charges have rearranged so as to cancel the applied field inside, the current stops.

 

If a charge is placed inside an ungrounded Faraday cage the internal face of the cage will be charged (in the same manner described for an external charge) to prevent the existence of a field inside the body of the cage. However, this charging of the inner face would re-distribute the charges in the body of the cage. This charges the outer face of the cage with a charge equal in sign and magnitude to the one placed inside the cage. Since the internal charge and the inner face cancel each other out, the spread of charges on the outer face is not affected by the position of the internal charge inside the cage. So for all intents and purposes the cage will generate the same electric field it would generate if it was simply charged by the charge placed inside.

 

If the cage is grounded the excess charges will go to the ground instead of the outer face, so the inner face and the inner charge will cancel each other out and the rest of the cage would remain neutral. A Faraday cage is capable of completely stopping an attack using electromagnetism such as an EMP.[citation needed']

 

The cage will block external electrical fields even if the cage contains some charges and an electric field in its interior. This is a consequence of the superposition principle and the fact that Maxwell equations are linear.

 

A Faraday cage will not shield its contents from static magnetic fields. However, rapidly-changing magnetic fields create electric fields in accordance with Maxwell's equations. The conductors cancel the electric fields and therefore the changing magnetic fields as well. The wall materials' thickness and skin depth set the frequency at which the cage suppresses electromagnetic fields. Static or slowly-changing magnetic fields penetrate the cage; rapidly-changing ones do not

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I have two epis with p90s.. one with plastic cream covers, one with metal chrome covers.

 

I was just playing in the living room, used both.

large tv was on.

 

I've not shield painted the metal p90s yet.. but I've used shield painting on the other..

 

you'll get noise off that tv screen.. you'll get noise standing close to the tube amp..

turn a it goes away..

the sheilding reduced this dramatically.. and copper foil works as well as paint.

 

tape over the coils is a good idea if they aren't metal covered, but probably not going to do much if they are.

you want to be sure to ground your sheilding to the guitars electronics.

 

For me, all this does is reduce the noise. nothing gets rid of it.

But instead of having one spot I can play in. I now only have one or two spots I can't play in.

 

I'd go metal covers, as much shielding as I can get in there.. and then be happy cause they are what they are.

and we know they're worth the hassle!

 

TWANG

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Commonly called "60 cycle hum," or "Mains Hum"...it's the hum, that happens when single coil pickups, are used around TV's, Refrigerators, neon or florescent lighting, and/or Anything Else that uses the 50-60 hertz alternating/occillating current. "Humbucker" pickups, using two coils (in series, but reversed polarity),

were developed to cancell out, that hum.

 

CB

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Commonly called "60 cycle hum' date='" or "Mains Hum"...it's the hum, that happens when single coil pickups, are used around TV's, Refrigerators, neon or florescent lighting, and/or Anything Else that uses the 50-60 hertz alternating/occillating current. "Humbucker" pickups, using two coils (in series, but reversed polarity),

were developed to cancell out, that hum.

 

CB[/quote']

 

Well, I tend not to play around any of those items, so that explains why I could never figure out why I never expereinced that with Strat or Wildkat.

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Well' date=' I tend not to play around any of those items, so that explains why I could never figure out why I never expereinced that with Strat or Wildkat.[/quote']

 

Well, you've been fortunate, then...OR, you're so used to it, you don't notice it.

Those, and other appliances, don't need to be in the same room, even.

Just on the same circuit, as you amp. We've had problems with neon signs, in bars/clubs, like the beer

signs, etc., or even the "fridge," that beer/food is stored in, in those place, do that. Overhead fans, vents,

Literally anything, that uses alternating current.

 

CB

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