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Input ground loop hum only when p10 cables or XLR without phantom power are connected

I own a Scarlett 2i4 (USB interface) and all of a sudden a ground loop appeared that only makes noise when p10 cables or XLR cables without phantom power (when I turn it on, it disappears) are connected. I’ve changed the cables several times and nothing seems to work. Please help!
pedropmk_
erik_squires
5,268 posts
 
@cleeds I was being a little severe, but I still think it's wrong.

If you are testing a device which is often connected to a source of noise, such as a laptop with charger, you should test with that noise, not do everything you can to eliminate it in the test environment.

In effect you are denying those manufacturers who go out of their way to eliminate ground loops and digital noise the chance to shine, and putting them on a level playing field with DAC's that don't take the extra effort.


mb1audio
151 posts
 
Some people call TRS connectors Tip Ring Sleeve. Those are not balanced. You need to make sure the 1/4 connector has 3 contact points, and that they are wired correctly.
jea48
2,944 posts
 

pedropmk,

Nothing is connected to any of the outputs? Correct?

The guitar and mike plug directly into the inputs of the Scarlett 2i4? Correct?

Are you sure what you are hearing is a hum and not a buzz?

Scarlett 2i4 User Guide

https://d3se566zfvnmhf.cloudfront.net/sites/default/files/focusrite/downloads/8174/scarlett2i4-user-...

Help Centre

https://support.focusrite.com/hc/en-gb



jea48
2,944 posts
 

I own a Scarlett 2i4 (USB interface) and all of a sudden a ground loop appeared that only makes noise when p10 cables or XLR cables without phantom power (when I turn it on, it disappears) are connected.

Phantom power? Do you mean engaging the 48V Phantom power button on the Scarlett 2i4 unit? Is the microphone you are using a capacitor (condenser) type? If yes the Phantom Power button should be engaged according to the User Guide of 2i4 unit.

] https://www.youtube.com/watch?v=2M7KejHXr8Y[

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