helix USB Causing Noise

[Goooner1]

I run my Helix plugged into my pc via USB and out to a pair of monitor speakers, I run all my pc sound through the Helix and it’s easy to run Helix Edit for experimenting with patches. 
 

Recently bought a Marshall DSL1HR and MX112 cab. Thought I’d try running the Helix into the front of that but I get horrendous white noise/static. 
 

After much swapping of cables it turns out that it’s the USB cable form the Helix to the PC that’s causing the issue, but only when I have the Helix plugged into the amp, not the monitors. 
 

Tries replacing the USB cable with one with two ferrite shields, one each end to no avail. 
 

Plugged the Helix into a USB hub which reduced the level of the noise but at the same time introduced a whine/hum type sound. 
 

If I connect the Helix to the amp (still connected to the pc) with my Xvive wireless it’s fine, no noise at all. So I could just use wireless, but then I need to remember to keep it charged and switch it off when I’m done

 

Any ideas how to solve the noise issue when using cables?

 

Have tried the ground lift button on the back of the Helix. 

 

[JLondon]

Yep.  That's what happens alright.  Not just you.  It's a ground loop and it's a problem for everyone wanting to plug into their computer and an amplifier at the same time.  There is a box you can buy on Amazon that you plug USB into before computer that a lot of people claim to have had good luck with but I don't recall at the moment what it is.  Do a Google search of ground loop Helix USB and you should find it pretty quick.  They're about $70 if memory serves correctly.

 

[PierM]

These noise problems are rarely caused by USB cables, but instead it's typically interferences produced by devices connected to the PC/Laptop, passing through. Try unplugging everything from that PC, apart the Helix, and see if does help.

 

In my experience, many times are PC monitors using HDMI ports, but can be virtually anything using a wall socket.

[Schmalle]

The USB cable completes a ground loop that acts as an antenna. The loop: socket 1 - power cable - Helix - USB cable - computer - power cable - socket 2 - socket 1.

This has 2 effects:

1) Electromagnetic fields inside this loop will be picked up. So  if you minimize the area the loop spans you minimize the noise it can pick up. Laying power cables in parallel next to each other helps, also using the USB ports in the back of the computer are usually better, because the loop now doesn't contain the inside of it where the cpu and other stuff produce electromagnetic noise.

2)The loop can also inject mains hum. That can be minimized by plugging PC and Helix into the same wall outlet using a multi socket.

 

Of course not closing the loop is best which can be done by using an USB isolator, but those aren't cheap.

If you use a laptop you can unplug it's power supply and prevent a ground loop that way.

[Goooner1]

Thanks guys. 
 

At least I know what it is no. I’ll just stick to wireless. 

[chasingMango]

I have both my helix and powercab in a custom cabinet, both usbs hooked up to a USB extender that runs it over a single ethernet cable to my computer.  Works great, and no noise!  I didn't notice any noise before, but  I rarely plugged in the usb, now there are plugged in all the time.

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