Scarlet 2i2 Interface-Ground Loop Noise

[chichi]

Hello Guys,

I have been using Scarlett 2i2 Audio Interface, and when I turn of 48V there is this annoying noise which I believe is a Ground Loop. When I unplug the power cable from the laptop the noise goes away. And when I connect it to an iMac also the problem is there.

I have contacted Focusrite about this issue and they suggested various remedies which haven't worked and all my friends who have been using this Audio Interface have had the same issue.

Any of you guys had the same issue?

Any suggestions?

Thanks
Chi

[Hugh Robjohns]

I've no idea why turning off 48V phantom produces this problem. A ground loop is present the whole time. And usually the loop exists between the computer and mains-powered monitor speakers, so the typical solution is to disconnect the ground connection that runs from the interface to each speaker via the screen of the balanced audio cables.

You can do that either by physically cutting and isolating the screen connection inside the plugs at the speaker ends -- being a balanced connection, the signal transfer does not require the ground connection, or by using an isolation transformer box like the ART DTI (others are available).

If the noise is related directly to the use of phantom power, then something else more insidious is going on...

[chichi]

My bad-That's a typo Im sorry-It should be when I turn ON 48V.

Thanks Hugh for the reply.

In this case I have not been using any speaker-I use Only headphones.

And I can see the noise being recorded in the project file which is really annoying.

[chichi]

Hello Guys,

I have been using Scarlett 2i2 Audio Interface, and when I turn ON 48V there is this annoying noise which I believe is a Ground Loop. When I unplug the power cable from the laptop the noise goes away. And when I connect it to an iMac also the problem is there.

I have contacted Focusrite about this issue and they suggested various remedies which haven't worked and all my friends who have been using this Audio Interface have had the same issue.

Any of you guys had the same issue?

Any suggestions?

Thanks
Chi

[Hugh Robjohns]

It should be when I turn ON 48V. In this case I have not been using any speaker-I use Only headphones. And I can see the noise being recorded in the project file which is really annoying.

In that case I'd say its unlikely to be a conventional ground-loop, and is more likely to be an issue with the power supply that generates the 48V.

What else is connected to the Scarlett?

What are you powering with the phantom power?

And assuming it's a mic, how is that mic physically mounted? (Just in case there's a ground path via the mounting arrangements).

[Jimmy B]

I don't know if the following is going to fix this specific problem, but I'm adding it in case it helps anyone.
I have a Scarlett 2i2 version 1. For most pueposes it is excellent. However, trying to record from an electric guitar using avDell laptop, I was getting an annoying buzz, which went away when I touched the guitar strings and also when I disconnected the laptop power supply, so that it was running on batteries.
The guitar gave no such problems when plugged into a real guitar amp.
A little research allowed me to determine that this particular laptop (and indeed most laptops) is not grounded even when it is mains powered, and therefore neither is the Focusrite Scarlett or the guitar.
To prove a point, I ran a spare cable from the spare input on the Scarlett to the input socket of the guitar amplifier. The important point here was to join the grounds of the two systems using the shield in the cable.
This experiment was totally successful. The buzz disappeared.
Having proved the point, I rigged up a proper grounding cable for the Scarlett. If you don't know how to do this safely, please consult someone who does, as there is potential for serious harm here.

[Martin Walker]

Hi Jimmy B, and welcome to the SOS Forums!

And what a helpful first post too

Ground loop and 'no ground' problems can result in very similar hums/buzzes, so your approach makes perfect sense to check that there's an earth at all.

However, in plenty of cases nowadays, ground loops tend to result in a wide range of scratches, ticking, buzzing and other digital gremlins that are often associated with computer activities such as graphic redraws, mouse movements, and hard-drive activity.

This is why (for the original poster) linking to a short audio sample of the offending interference can help in identifying the most likely cause of a particular problem.

Martin

[eva.pepe@gmail.com]

I also have a ground loop noise issue. It seems to be in the connection between my mac laptop (unplugged) and the Scarlett 2i2 interface. I have read about the iFi audio iDefender helping to fix this problem https://www.bhphotovideo.com/c/product/ ... l/overview

Has anyone tried this product?
I can send a sound sample of my noise if I can figure out how to attach it in this post.

Edited to remove what appears to be an affiliate link - JP

[Sam Spoons]

Does the noise go away when the laptop is plugged in*? If not and a, the 2i2 is bus powered by the laptop and b, the laptop is unplugged, your problem will be the opposite of a 'ground (earth) loop' and removing the ground/earth between the two will not help. First thing to try is to connect something with a known good earth to the system, maybe a mains powered guitar amp, and see if that helps.

* Not all laptop power supplies have a good, low resistance earth so plugging it in may still not solve the problem.

[Hugh Robjohns]

I also have a ground loop noise issue. It seems to be in the connection between my mac laptop (unplugged) and the Scarlett 2i2 interface.

Think about it... where is the ground loop? The laptop isn't connected to the mains Earth and neither is the bus-powered interface. So where's the ground loop?

In fact you have the opposite problem. Instead of too many ground connections you have none. The system is 'floating' which means any noisy interference doesn't get carried away to Earth where it can do no harm, but gets added to the audio instead.

Connect something properly grounded to your groundless interface and your unwanted noises will almost certainly go away.

Edit: sorry, didn't read Sam's reply before typing my own... But nice that we are on the same page.

[eva.pepe@gmail.com]

Thank you both for your very prompt replies, and to others who have contributed to this thread. And I apologize for not giving you more details about my setup. My goal was to export music tracks from my old ZOOM MRS-1044 recorder and input them to GarageBand. I assume that the ZOOM was the grounded component in this situation. I used an RCA to RCA (1/4") auxiliary cable and connected it to the headphone output on the ZOOM and the instrument input on the Scarlett 2i2. This actually worked well, except for the high-pitched noise. I referred to an earlier post about phantom power and tried turning it off. Voila! No more noise.
Thanks again to all!

[Faitherino]

I found that when I touched my mic it gave off this low and heavy humming noise, I sat for like 30 min trying to troubleshoot. I changed the cables position, I tried switching usb cables. Nothing worked and when I held my hand on the metal part of the xlr cable going into the interface it stopped even when I didn't touch the mic.

I sat for 5 more min and touched around all the metal parts, turns out that the holder on the mic stand for the mic wasn't FULLY screwed in, I screwed it in tight and the humming stopped completely...

This was my grounding issue and solution to it.. It plagued me for 3 weeks..

[Sam Spoons]

Hi and welcome to the forums.

To properly understand what is going on here more info on your rig is required, please can you post a detailed list of your gear and how it is connected?

On the surface you solution sounds improbable, how would the connection between a mic mount (plastic?)* and a mic stand (usually on rubber feet and/or carpet/vinyl flooring) change the earthing on your rig? Clearly I'm missing something but it would be unusual for the mount/stand to be carrying any sort of earth connection.

* A LDC with a screw on mount would probably be metal but even that could not be relied upon to provide a good earth...

[Faitherino]

Hi Sam.

My gear is the literally just the studio package Focusrite 2i2 3rd Gen.

The thing I believe, and the only thing I could think caused this, was that the ground pin in some way shape or form wasn't connected fully, therefore the grounding issue. When it wasn't screwed in properly and I touched the actual mic mount that comes with the mic, not the actual mic stand itself, and wiggled it I could hear sparkling. The issue wasn't in the mic stand, I hope this clears it, if there is anything else please ask more, I'm a bit tired and not the best at typing.

The way it is connected is literally just through an xlr cable straight into port 1 nothing weird. I must have unscrewed it a little by mistake when moving the mic around at some point in time.

Also the humming could be heard clearly when the selfhearing was enabled and the mic was touched but stopped when I touched the metal part of the cable going into the interface. Otherwise it was a very quite humming.