The iFi audio iDefender+ is a device designed to combat audio interference caused by unwanted ground loops in the audio chain. When connected to the USB socket of the source equipment, the iDefender+ detects if there is a ground loop problem. It breaks the ground loop by 'intelligently' disconnecting the computer's ground, which not only eradicates audible ground loop hum, but also lowers the system's noise floor, improving resolution and dynamic contrast1.
In addition, the iDefender+ offers an extra benefit if used with a DAC (digital-to-analogue converter) that relies on USB power from a computer rather than power from the mains or a built-in battery. If an external power supply is connected to the USB-C socket on its side, it blocks power from the computer and instead feeds the DAC with 'clean' power from the external supply. If a high-quality, low-noise power adapter such as iFi's iPower X is used, the performance of the USB DAC will be significantly improved1.
iDefender+ now comes in three versions and includes the newer USB-C connector:
USB-A to USB-A
USB-C to USB-A
USB-C to USB-C
iFi has upgraded the circuit with low-ESR count capacitors for improved input and output filtering, and the filtering capacity has been increased tenfold1.
Ground loops in an electrical system occur when two points in an audio system both have a ground reference causing a 'potential voltage difference' between them. Ground loops are a major cause of noise, hum and interference in audio, video and computer systems1.
To "break" the earth/ground loop on USB-powered DACs, it is necessary to add a separate 5-volt supply. This is not required for DACs with an internally powered USB section1.
