Helix USB / PC ground loop isolation issue

[cometphoton]

Please help I have a ground loop USB problem. 

 

Helix LT with usb connection to a Windows 11 PC. Line 6 Workbench and HX edit software.   Focusrite 18i20 usb interface to pc and helix has a stereo connection via analog to helix. Variax connected to Helix via digital cable. Roland KC-550 connected to the focusrite via balanced cables.

 

Anyhow when i move the PC mouse i hear a buzzing sound thru everthing. Well thru process of adding balanced cables to everthing but the guitar I found this. When I disconnect the usb cable between the Helix and the pc the buzz is gone. This is nice but I like to use my line 6 software too. 

 

Did anyone find a usb isolator that you can put between PC usb and Helix Usb that works ? I tried this one and it did not. (  Jhoinrch USB Isolator Onboard ADUM3160 Chip ). 

 

What Usb type and what speed dose the Helix require. Anyhow this is one for the EE that designed the product. Need to add Isolation to the next gen so this is gone via the helix processor / interface / electronics.

 

 

  

[SaschaFranck]

Are you using the balanced XLR outs from the Helix to your interface? If not, I'd try using those first and check their ground settings, too.

[Schmalle]

Ground loop means that your Helix has at least two ground connections to your PC (one via USB and two via 1/4" Outs).

 

Connect via XLR and engage the GND Lift. Then you have one ground connection and the noise should be gone.

[cometphoton]

Purchased a Topping HS02-bk Isolator, Bingo!! no more noise. Yahoo!!!

 

Note: Schmalle is right about the grn loops. The two 1/4" outs and the usb in unison created my noise problem,

So when you remove both 1/4" cables the noise goes away.

 

I will order two balanced cables replace my 1/4"unbalanced. Then let eveyone in on what happens. 

 

Thanks

On 9/20/2026 at 1:05 PM, SaschaFranck said:

Are you using the balanced XLR outs from the Helix to your interface? If not, I'd try using those first and check their ground settings, too.

 

 

[cometphoton]

Everyone hit the nail on the head. Instrument cables (2 wire) caused ground loop. XLR balanced is the best senerio.

One XLR cable caused a low hum too. The Cable nomenclature = low noise.  Replaced it now: No PC mouse noise and no hum.

Thanks for helping me with simple solution. 

 

[Schmalle]

On 9/22/2026 at 3:35 AM, cometphoton said:

Everyone hit the nail on the head. Instrument cables (2 wire) caused ground loop. XLR balanced is the best senerio.

One XLR cable caused a low hum too. The Cable nomenclature = low noise.  Replaced it now: No PC mouse noise and no hum.

Thanks for helping me with simple solution. 

Ground loops are a very common problem with audio gear in general.

 

Balanced signals work without ground connection - so the GND lift most often is the best option to open / eliminate the loop. 

 

For ground loop issues where that is not an option the Behringer HD400 / Pyle HDE 300 is my general recommendation - basically a transformer based galvanic isolation box (like in most D.I. boxes), but two channels and with TS ins and outs.