Re: [PLUG] Ground Loops / Hum

[Casey Bralla via plug <plug@lists.phillylinux.org>]

Good ideas, Martin.  I'll check this out.  Thanks!

On 3/24/25 5:05 PM, Martin Cracauer via plug wrote:
> Casey Bralla via plug wrote on Mon, Mar 24, 2025 at 03:34:30PM -0400:
> > So how should I kill the ground loop?
> You should first confirm that it is what you think it is.
>
> Have a headphone amp at the soundcard directly.  Is the hum gone?
>
> Connect just one in-the-wall cable? Is the hum there?
>   
> > I tried enhancing the earth ground connection to the shielding, but this
> > didn't help.
> The opposite is appropriate, terminate the shield connection of the
> cable on one end.
>
> Another possibility is transformer-based isolation devices.  Same
> principle they break ground.
>
> > One thought I had was to separate all the grounds at the distribution box.??
> > Each cable run to the distribution box would be grounded only to its
> > individual amplifier.?? This means the signal lines will still be shielded,
> > but will be floating relative to ground.?? Is this acceptable practice?
> Yes.  But only if it is a true ground loop.  Which hum often isn't.
>
> Martin
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