Building a Faraday's cage ?

[John O'Flaherty]

It clearly has a big effect on power wires in my walls - i can hear a loud
noise if i put my emg707 very close to a wire in my wall and that noise gets
much quieter if i turn my guitar 180 degrees to face away from the wall and
hold the pickup at the same distance to the wire.

If you can look at what load is fed through those particular wires, you
might be able to turn it off as an experiment. If there is no load on
the wires, there will be no current or magnetic field. If the noise is
still present, you could conclude that it's electrostatic.

 

[Phil Allison]

"CS" = one STUBBORN, SOB, graphic artist Puke

Ok if i am an idiot and you know better then you must be smart enough to
eplain to an idiot why "That scenario PROVES the direct opposite" ?

** HUH ???

YOU need to say how the HELL it demonstrates YOUR MAD CLAIM first.

My guitar (in my room) is ~30 dB quieter than my cousin's (genuine) strat.

** Fender Strats are the VERY WORST environmental hum field receivers
ever sold !!!!

The stupid, plastic covered, single coil PUs are not even ES shielded !!!

Most of the wiring is NOT shielded

Buzzzzzzzzzzzzzzzzzzzzzzzzzzzz..........

Do you realize that there is no humbucker on this planet that will buck
100%
of hum ?

** What PEDANTIC TWADDLE.

GROW UP - you PITA BLOODY FOOL ! !







........ Phil

 

[Phil Allison]

"CS" = COMPLETE SHITHEAD !



** Add dumb as dog shit to.





....... Phil

 

[Earle]

"CS"


** That hum is being injected MAGNETICALLY into your guitar's pickups.

A Faraday cage will have NO effect on it - whatever !!

FORGET IT !!

Your ONLY option to eliminate the hum is to get a guitar that has "
hum-bucking " pickups.

The hum problem YOU are having is WHY they were invented, way back in the
1960s.

Most musicians learn to live with it by orienting themselves when playing
to minimise the hum and/or using a *noise gate* to silence the hum when the
guitar is not being played.

BTW

I can hardly believe how many FUCKWITS posters here have given you the
WRONG answer for such a common problem.

They got you to help them. Not so dumb are they?

 

[[email protected]]

Hi

I have a small bedroom recording studio full of electromagnetic fields
(mainly 50hz+harmonics up to ~3,5khz from power cables in walls).

Here is how it looks on Adobe Audition's spectrum analyzer:
http://img158.imageshack.us/img158/4522/dirtysilence7th.jpg

I'm planning to build a 2m x 2m Faraday's cage/booth to protect active
electric guitar pickups from external electrostatic and electromagnetic
noise 20hz-96khz

Please suggest best material (copper ? aluminium ? iron ? or maybe a
combination of different metals), how thick should it be and how to get rid
of the current in a situation where no true ground is available.

How many dBs of attenuation should i expect ?

Thanks in advance.

ps. If this is not the right newsgroup to ask this question please suggest
the best one.

You should be able to know what the field is first. Take your equipment
common and attach a wire to a piece of aluminum window screen or just
plain alauminum metal. Wave it around with the guitar fixed. Then take
a fairly large piece of steel and wave it around. If the first method
made changes then thats a electrostatic field, and the second magnetic
and partially electrostatic.

GS

 

[Bob Masta]

Hi

I have a small bedroom recording studio full of electromagnetic fields
(mainly 50hz+harmonics up to ~3,5khz from power cables in walls).

Here is how it looks on Adobe Audition's spectrum analyzer:
http://img158.imageshack.us/img158/4522/dirtysilence7th.jpg

I'm planning to build a 2m x 2m Faraday's cage/booth to protect active
electric guitar pickups from external electrostatic and electromagnetic
noise 20hz-96khz

Please suggest best material (copper ? aluminium ? iron ? or maybe a
combination of different metals), how thick should it be and how to get rid
of the current in a situation where no true ground is available.

How many dBs of attenuation should i expect ?

Thanks in advance.

ps. If this is not the right newsgroup to ask this question please suggest
the best one.

As others have noted, this problem may not be helped by
a Faraday cage, which only provides electrostatic shielding.
But it should be easy enough to test this for yourself, by
wrapping your guitar in aluminum foil. (You should first
wrap it in plastic so the foil doesn't contact the strings.)
Then ground the foil... presto! A mini-Faraday cage!

Don't worry about the fact that Faraday cages usually
use copper mesh. The difference here will be trivial,
except to your wallet.

I'll be surprised if it solves your problem, but at least
you'll know quickly and cheaply. And if it doesn't,
I don't have any tricks to offer.... I've also had plenty
of hum problems from alleged humbucker pickups.
Which is pretty annoying considering that they cost
more, sound worse, and have lower output than
ordinary "hot" pickups.

Best regards,




Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Home of DaqGen, the FREEWARE signal generator

 

[Meindert Sprang]

As others have noted, this problem may not be helped by
a Faraday cage, which only provides electrostatic shielding.
But it should be easy enough to test this for yourself, by
wrapping your guitar in aluminum foil. (You should first
wrap it in plastic so the foil doesn't contact the strings.)
Then ground the foil... presto! A mini-Faraday cage!

Two corrections:

1) a faraday cage shields agaist electrostatic and magnetic fields, in case
of an AC field.

2) a faraday cage does not need to be grounded.

Meindert

 

[GregS]

Two corrections:

1) a faraday cage shields agaist electrostatic and magnetic fields, in case
of an AC field.

2) a faraday cage does not need to be grounded.

Thanks for the definition. In this real world situation, you
have an imperfect cage, and you have things inside coupled
to the outside.

greg

 

[Phil Allison]

You should be able to know what the field is first.

** Straight from the Twilight Zone.....







......... Phil

 

[Phil Allison]

"Meindert Sprang Dutch Fuckwit"

1) a faraday cage shields agaist electrostatic and magnetic fields, in
case
of an AC field.

** Crapology !!!!!!!!!!!!!

There is ZERO attenuation of low frequency magnetic induction.





........ Phil

 

[Phil Allison]

"GregS"

Thanks for the definition.

** NEVER mistake a *Daffy Notion" for a "definition".

Be like mistaking shit for chocolate.

Yuckee poo..........





....... Phil

 

[John Larkin]

The worst are nearfield magnetic, eg a train passing
5m from your house. At the time of CRTs, it was
impossible to work during the time the current flowed
through the rails. And it wasn't shieldable. As
John Larkin said, for a decent magnetic shielding,
eg 120dB up, you need substantial amounts of iron.

A Hoffmann 14-gauge formed-and-welded steel electrical enclosure is a
pretty substantial hunk of metal, and won't dependably attenuate a 60
Hz magnetic field by 2:1, a mere 6 dB. And the bigger the box, the
worse the shielding.

John

 

[Phil Allison]

"jasen"

guitars use unbalanced cables.

** Matches the *unbalanced* players .





...... Phil

 

[Frank Raffaeli]

"jasen"



** Matches the *unbalanced* players .





..... Phil

Q:How do you know when the stage is level?








A: The bass player is drooling out *both* sides of his mouth

---------

Q: What do you call a drummer that just broke up w / girlfriend?










A: Homeless

Couldn't resist.

Frank

 

[Eeyore]

Hi

I have a small bedroom recording studio full of electromagnetic fields
(mainly 50hz+harmonics up to ~3,5khz from power cables in walls).

Here is how it looks on Adobe Audition's spectrum analyzer:
http://img158.imageshack.us/img158/4522/dirtysilence7th.jpg

I'm planning to build a 2m x 2m Faraday's cage/booth to protect active
electric guitar pickups from external electrostatic and electromagnetic
noise 20hz-96khz

You're wasting your time !

I do know a guy who built a huge Faraday cage in Mark Knopler's studio in London
btw.

Graham

 

[Eeyore]

1 No lights were on at that time.
2 I'm pretty sure it is from power cables inside my walls - i can detect
them (the cables) with my guitar.

You need a different guitar.

Graham

 

[Jim Thompson]

You're wasting your time !

I do know a guy who built a huge Faraday cage in Mark Knopler's studio in London
btw.

Graham

In my day they were called "screen rooms". We had one at Motorola SPD
that was 10' X 10' X 10', 2" X 6" studs, wire mesh on both surfaces.

...Jim Thompson

 

[Eeyore]

In my day they were called "screen rooms". We had one at Motorola SPD
that was 10' X 10' X 10', 2" X 6" studs, wire mesh on both surfaces.

...Jim Thompson

There was something pretty similar to that at Kelvin Hughes radar. Interesting place
to work for a while.

Graham

 

[Rene Tschaggelar]

"Meindert Sprang Dutch Fuckwit"


There is ZERO attenuation of low frequency magnetic induction.

Almost.
The currents induced in the conductor take
energy off the field and thus attenuate it.

Rene

 

[Phil Allison]

"Meindert Sprang - Dutch Fuckwit "


** Sorry for the tautology.

Almost.

** Exactly.

The currents induced in the conductor take
energy off the field and thus attenuate it.

** Crapology.




......... Phil