Grounding / Shielding Question

[Merlin Zener]

Christopher_List at sonymusic.com wrote:
> 
> [...snip]
> Question - can shielding work like an antenna rather than a shield?

I'll preface my comments with the disclaimer that I'm not really an
expert - just my impressions based on various experiences in the
field...
Yes. I think the thing is to make sure the case/shield is properly
grounded. 

> What if
> you're using a dual supply and the ground for the power supply isn't
> connected to earth ground (like the power cable has a ground lifter on
> it).

{image: Will Robinson's robot, with arms waving wildly}
WARNING WARNING WARNING WARNING WARNING WARNING
Lifting ground on the power is very dangerous, as well as illegal
(here in Australia, at least). The only reason you should have to
lift an earth is if you are having earth loop (hum) problems, and
then the answer is never to lift the power earth. You should lift
the earth at the source end of the audio cable, and or use a
balancing transformer if necessary. The point is, the shield of
the cable is connected to the case on the recieving end (still
providing shielding) and lifted at the source end only if you
need to.

> 
> Does the thickness of the material used for the shielding make a
> difference?

Sorry, I'll have to defer to others on this one...
 

-- 
Merlin Zener                                 phone (+61) (0)7 5578 5011
Musician, Technician                           fax (+61) (0)7 5578 5311
Gold Coast, Australia                           email merlin at ion.com.au
                                          http://www.ion.com.au/~merlin

           "research shows that no-one ever went blind from
                 looking on the bright side of life"