Breaking earth loops ?

Emp_Fab

So I've got an old iMac running Pro Tools and an MBox 2 mini usb interface.

I'm getting a 1kHz whine through my speakers when I connect them to the MBox.  I don't get any whine when I plug headphones directly into it, so it's an earth loop problem.

I don't particularly want to disconnect the earth lead from either the amp or the iMac (which world solve the issue).

I do have an old Radio Shack isolator somewhere (basically a 1:1 audio transformer) but I remember that dulling the top end a bit.

Any (sensible) suggestions for fixing an earth loop like this?

steamabacus

Orchid do a dual transformer isolator. I have a couple of their single isolators - very good quality transformers and I've never noticed a drop in sound quality.

PrecisionGuided

What's the connection from MBox to speakers? - balanced or unbalanced?

If balanced to balanced disconnect the signal earth at one (MBox) end.

Emp_Fab

It's a bit like me, unbalanced.

nero1701

Emp_Fab said:

It's a bit like me, unbalanced.

I'd say unhinged

Macca_25387

an ART dti box may help.

grappagreen

Emp_Fab said:

It's a bit like me, unbalanced.

May want to go for a pseudo balanced cable as per;

https://www.soundonsound.com/techniques/ground-loops-explained

Si