Ground Loops

In an electrical system, a Ground or Earth loop occurs when two points of an audio system both have a ground reference which causes a ‘potential voltage difference’ between them. Ground loops are a major cause of the noise, hum, and interference in audio, video, and computer systems.

iFi audio iDefender
Tired of doing battle with buzz, hum and hiss?

Our iDefender3.0 is for those struggling with noisy audio due to unwanted ground loops in their audio chain.

Bah humbuzz!

Annoyed by hum and buzz invading your listening?

Using multiple plugs means separate earth points. These multiple earth or ground points cause earth/ground loops and create an unwanted chain of noise, buzz and distortion.

iFi audio iDefender

Break the earth loop

The iDefender3.0 plugs into your computer USB port and auto-detects if there is more than one earth and will ‘intelligently’ disconnect the computer earth for cleaner sound.

Using a USB DAC?

If your DAC is USB powered, the iDefender3.0 requires an external 5 volts to break the earth. It works pretty well with our 5-volt iPower (just saying!). Injecting clean power will ensure you get the maximum out of your USB audio.

Inject 5 volts of clean power clean via the ‘separate’ micro port. This disconnects the USB power from the PC and replaces it with clean external power. For ultra-low noise, use our 5-volt iPower X.

Adding the separate 5 volts to the unit is necessary to ‘break’ the earth/ground on USB-powered DACs. This is not required for DACs with an internally-powered USB section.

iFi audio iDefender

So, why USB3.0? USB3.0 allows for a greater amount of audio transfer due to the better wiring specification. It is still backwards compatible with USB2.0.

Kills USB power noise by ‘breaking’ the earth/ground loops in the correct way.

It significantly reduces the system noise floor and makes for better dynamic contrast, warmth and resolution.


Super-Speed USB3.0 (and USB2.0 backwards compatible)
Connec­­tors: USB3.0 gold-plated connectors
Dimensions: 48 (l) x 18 (w) x 8 mm (h)
Weight: 6.5g (0.23oz)
Warranty period: 12 months


No more noise / ground loop

In my home studio I had ground loop problems by connecting my guitar preamp / audio interface (line6 hx stomp) to my PC via USB and then to my monitoring speakers via jack, with an infernal noise. I tried in vain all the advice of the guides: quality power strip with IRF filter, quality balanced XLR cables, ferrite rings on all cables. The noise still present.

Then I found this miraculous device that connects between the PC and the audio interface, creates a new ground for the USB device and thus eliminates the loop and noise. It saved my sanity, I highly recommend if you have the same type of problem. It is compatible with high speed USB devices.

(Click name to read original review)


iSilencer3.0 iDefender3.0
Primary useHomeHome
Who is it for? Generalist-for reduced USB port noiseSpecialist-for breaking Ground loops
Also inject clean 5v via additional iPOWER
(External power supply needed for iDef3.0 to break the Ground when USB-powered DAC is used. Not required if USB is internally-powered by DAC.)
USB standard (max)USB3.0 Super-speed 5GbpsUSB3.0 Super-speed 5Gbps
Active Noie CancellationYes-
Reduced jitter Yes-
IsoEarth (auto)-Yes
Inject 5v for clean power (iPOWER rec. )-Yes
Dimensions48 (l) x 18 (w) x 8 mm (h) 48 (l) x 18 (w) x 8 mm (h)
Weight6.3g (0.22 lbs)6.5g (0.23 lbs)