The iFi Gemini Dual-Headed USB cable will rule them all. Audio and power cables are not laid side by side yet in the USB configuration because of its origins, transmits this way. The iFi Gemini carries Audio + Power in two separate cables. Critically, the special geometry adheres to the 90 ohm impedance specification better than even the USB 2.0 standard. Resistance is 4x lower than textbook. The FINAL USB machined connectors provide impeccable shielding from end-to-end. The atypical silencer design spans the whole of the frequency range to totally banish all noise.
With this unorthodox array of features, the iFi Gemini Dual-Headed USB cable sonically, eclipses them all.
The Gemini cable adheres to the 90ohm specification of the USB transmission protocol exhibiting just a 1% deviation from the 90ohm impedance end-to-end (ie. connector + cable together).
Other expensive audiophile cables by comparison, vary as much as 15% (or 78ohm-103ohm!) This one key parameter is often overlooked yet is essential to maximise the quality of the signal transfer.
Design – What’s wrong with the current USB cable design for audio use?
As standard USB cables combine power and data into a single cable, and each interferes with the other.
The key of course is the “twin connection” design. It separates the signal ground from power ground and shields the signal and power connections from each other. Power and Audio signals are individually transferred and no interference between them is possible.
Connectors – What’s wrong with the connectors on the common USB cable?
Most USB Cables use moulded plastic covered connections. Of course, this plastic cannot shield the high frequencies present in the USB Data link, so noise radiated out. Durability is also compromised.
The FINAL USB machined connectors provides impeccable RF shielding from end to end, being entirely made from solid Aluminium. Goldplated connections make for the best conductivity over the long-term.
The RF3 system
Fit three custom made metal oxide ceramic RF noise silencers with different effective ranges, thus broadening greatly the range over which RF noise is silenced. Further the middle filter may be adjusted (moved along the whole length), to “detune” the antennae formed by the cable, depending on the conditions and requirements in the system. The other two silencers are left to be located at each end.
Shielding – What’s wrong with the shielding on the common USB cable?
Often only one shield is used; aluminum metalized foil is commonly used instead of copper shield.
Dual heavy shielding, use of both aluminum foil and copper braid shields, each work for different frequency range to produce the best shielding ever.
They also employed custom-designed metal connectors (not just for looks) to provide impeccable shielding from end-to-end.
Conductors – What’s wrong with the conductors inside with the common USB cable?
The cables used are thin (common are 28 Gauge / 0.08mm2 for signal and 26 Gauge / 0.13mm2 for ground and power). Further, power and signal grounds are combined into a single conductor with low cross-section, causing poor ground connections. Generic coppers or steel cored wires lower conductivity increases resistance and noise.
Many cables suffer from poor impedance matching and this makes operation at the USB speeds needed for high sample rates unreliable.
The signal connections use OFHC continuous cast copper, with much larger cross-section for the signals and 0.41mm2 for the signal ground. The geometry is then adjusted to keep the correct impedance. We also have very stringent requirements for impedance tolerance, much narrower than the USB 2.0 standard allows.
For power ground and power lines we have totally separate 0.5 mm2 connections offering 4 times less resistance in the power connection than common and providing the advantages of star grounding.
Keeping cable resistances low allows for excellent power delivery to the USB audio device from our iUSB Power. The iFi Gemini Dual-Headed USB Cable cuts power supply resistance in the USB link threefold compared to “textbook spec” cable!
Insulation – What’s wrong with the insulation used within the common USB cable?
Common cables use PVC insulation. PVC not only has poor dielectric behaviour, the softeners in the plastic can also cause the copper in the cable to oxidise (and may be toxic!)… PVC is very cheap to make though.
Some claim that Teflon® insulation is the non plus ultra of isolators. Yet combined with the metal conductors in cables it causes triboelectric discharges often into the tens of millivolts creating high frequency interference.
Instead we combined PE insulation with the copper conductors; PE and copper combine to produce some of the lowest triboelectric discharges in cables available today.
All this means that the Gemini Dual-Headed USB Cable objectively produces much improved results for power and data transmission via USB.
How does it sound?
Well, once you try such an optimised and proper USB cable design (i.e. iFi Gemini Dual Headed USB cable), you realise just how much compromise generic and other so-called audiophile USB cables bring to the system.
Perfect match with iFi iUSB Power.
- Dual-headed (Gemini) connection USB transmission design
- Triple RF silencers (adjustable) to tune cable to environment*
- Asymmetric Ground return and power line design (4x lower resistance)*
- ’FINAL’ USB machined Aluminium Alloy connectors
- Heavy OFHC continues cast copper (up to 5A)
- Double shields with different effective ranges
- Custom Polyethylene insulation for lowest triboelectric discharges