iFi iDefender+ USB Audio Ground Loop Eliminator (Type C > C)

iFi iDefender+

In recent years, more and more music lovers have taken to using computers as their primary audio source. These are often connected to audio gear via USB – the universal interface that enables digital data to pass from one piece of hardware to another.

The iDefender+ is a more specialised USB audio device, specifically designed to tackle ground (or earth) loops that can cause real issues with some computer-based systems, typically resulting in an irritating buzz or hum from the speakers.

The iDefender+ upgrades the performance of the outgoing iDefender3.0 with the addition of low-ESR Tantalum capacitors for input and output filtering. It, too, is available in three versions to suit the connected equipment

USB-A to USB-A,

USB-C to USB-A, and

USB-C to USB-C.

The USB3.0 and USB2.0 standards are supported and the connectors are gold plated.

iDefender+ A-A

When plugged into the source device’s USB socket, the iDefender+ detects whether there is a ground loop problem, caused by the presence of multiple earths that add noise. It breaks the ground loop by ‘intelligently’ disconnecting the computer’s earth; as well as eradicating audible ground-loop hum it lowers the system noise floor, improving resolution and dynamic contrast.

iDefender+ C-A

When used with a DAC that relies on USB power from a computer, rather than power from the mains or a built-in battery, the iDefender+ offers an additional benefit. If an external power supply is plugged into the USB-C socket on its side, it blocks power from the computer and instead feeds the DAC with power from the external supply; if a high-quality, low-noise power adapter such as iFi’s iPower is used, the performance of the USB DAC will be significantly improved.

iDefender+ C-C

In the audiophile realm, we aim to reach as pure a digital stream from the PC to the speakers as possible. Given the issues and limitations designed into USB audio, it should come as no surprise that USB devices may be created that are found to improve the sound quality.

Diagnosing Audio Hiss

The 'touch' test. When you touch your device, does the hum/buzz noise increase? When you let go, does it decrease again?

If so, this is likely to be caused by a missing earth/ground connection.

This connection normally shields your system from such interference and drains away the noise.

If not, then this is because of the multiple earths. This then adds excess and unwanted noise. This is when the iDefender3.0 comes to the rescue.

Tech Specifications

Super-Speed USB3.0 (and USB2.0 backwards compatible)

USB3.0 gold-plated connectors

Dimensions: 50(l) x 20 (w) x 9mm (h)

Weight: 6.6g (0.23oz)

What is wrong with the USB-signal for audio devices?

It must be understood that USB audio devices have much more demanding requirements for USB hardware and software layers than any other USB devices, such as printers, hard drives or flash drives.

Further, USB Audio Class 2 devices (2 Channels@32Bit/768khz) have even greater requirements due to the much higher throughput at high sample rates compared to USB Audio Class 1 devices (2 channels@24Bit/96kHz). They must run at a much higher speed even if only streaming lowly CD standard signals. The key issue is that USB Audio Class devices use ‘Isochronous’ transfers while other devices use ‘Bulk/Burst mode’ transfers.

What is Isochronous Mode?

The isochronous mode is used for media streaming because it assures bandwidth on the USB by scheduling one transfer per available frame. By comparison, Bulk or Burst transfers make use of ‘leftover’ bandwidth and may be ‘choked off’ if higher priority isochronous data transfers saturate the USB. The isochronous transfer mode uses error checking but includes no re-transmission in case of Cyclic Redundancy Check (CRC) errors. Electrical noise on USB signals causes CRC errors and thus data loss, as does poor signal integrity. These lead to many potential causes of symptoms like audio signal distortion, artefacts (clicks/pops/crackling), and latency. It means that in order to reach the full potential of a USB audio device, the USB signal quality has to be excellent, and no CRC errors occur.

Note: Do not confuse ‘asynchronous USB’ with ‘Isochronous,’ an asynchronous USB system still uses isochronous mode to transfer audio.

• REMOVE UNWANTED NOISE - Silence buzzing caused by unwanted ground loops from your audio chain at home or in your car sound system. Available in 3 connection versions: USB A input to A output, USB C input to C output, USB C input to A output
• DEFEND AGAINST TOO MANY EARTHS - Disconnects the USB power from the PC, laptop, or other USB music source to eliminate multiple earths which cause noise interference
• IMPROVE SOUND QUALITY - Significantly reduces system noise floor and increases dynamic contrast, warmth and resolution in your music with a measurable difference. Retains USB 3.0 high speed data transfer technology for optimal signal transmission
• ROOM FOR MORE SOLUTIONS - Use an iPower 5V power supply (sold separately) into the side USB C port for clean DC power on USB powered devices. Not to worry, other 5V power supplies used will benefit from additional noise filtration
• NOTE: The iDefender+ is only a solution for noise generated by having too many grounded devices in your audio chain. If the noise is created by any other source, we’re happy to help discover an alternative