UR28M ground screw

Hi all,

Just received my UR28M and it seems I have ground loop issues.

The config I want to achieve is very simple: laptop → UR28M → 2 * HS7

The “hum” is very loud and annoying in the monitors, and is even there if I use headphones.
As soon as the UR28M has a metallic contact with my laptop powered by AC, even if I don’t plug the cable, the “hum” appears. Also if I unplug the charger from the laptop while it’s still running, the “hum” completely disappears. This makes me think it’s a ground loop issue.

I’ve spent these last 2 days looking for a solution unsuccessfully (I spare you the details and all the discarded solutions), and my last resort before I ask for a refund seems to be the ground screw at the back of the UR28M.

The manual says: “For connection to a ground wire. If you have a problem with hum or noise, use this terminal to connect to ground. The noise may be reduced.”

I’m no electrician, and this is very poorly documented. What is the safe procedure to achieve this? What do I have to do exactly?

Thanks in advance for your answers!

There are a few things you can try, but it would be better to have someone knowledgeable check it out.
One simple thing you might try however is reversing the adapter plugs (which are usually 2 prong) in the power sockets. Do this one at a time and try all configurations. It’s also a good idea to have all devices (including your active speakers) plugged into the same power bar if possible.

You can safely connect a wire from the ground screw to something grounded in your place, like a water pipe, or radiator.

On my UR44 I tried grounding it with poor results though. Running balanced XLRs cables from the main outs to my Event 20/20s fixed it completely, no more more hum or other noise (computer generated stuff).