"Arny Krueger" wrote

I'm replacing the unshielded power cord on a microphone
preamp.

Elsewhere you talk about foil wrap and standed wire shielding.
Please clarify - is this cable shielded or not?

See product description on my 2nd post.


Besides having an insulated ground wire there is
a raw wire lead.

That would be the drain wire for the foil shield.

And the braid wire shielding, too.


That raw lead is attached to the plug ground, of course,

Not a given.

No, it is based on meter reading.


but in addition to the foil wire wrap and in turn to the
stranded wire shielding.

That's what drain wires do.

Why are four electrical pathways needed?


What is the purpose of the raw wire lead and what
should be done with it?

Its the thing you use to make an electrical connection
to the foil wrap.

That's clear as mud.


I was under the impression that for maximum RF/EMF
rejection the coax shield/foil only drained into the common
ground of the plug, not to the equipment itself.

The drain wire can be used either way, or both.

Unlikely, otherwise why would the manufacture design
the cable this way giving one choice?


Consider that the world is full of mic preamps that have
unshielded power cords and work just fine.

OSAF


The shielding serves very little purpose in many
environments where the power wiring in the building is
unshielded. Any interference that the shelded cord may
wish to protect the power wiring from can easily come in
via the unshielded wiring in the building.

Which is why the amp is connected to a power conditioner
with RF/EMI filtering with a isolated transformer.
Unfortunately there are several other cables together with
this one like power, analog, digital, ect.