iFi Audio iUSB Power ($229 new) and 1.5m Gemini USB cable ($265 new) with iFi Type B to Micro adapter and ultra low noise power supply.  Herndon Audio ships the same day payment is received, shop with confidence and look at our hundreds of positive feedback transactions over the past 13+ years.  Herndon Audio can take all credit cards, PayPal, AudioGon Express Checkout (Stripe), check, etc.  Price includes shipping, insurance, and transaction fees, everything to your door. 

iFi iUSBPower Power Supply

The iUSB Power is the World's Only Ultra-Quiet USB Power Supply - Quieter Than a Battery

Bypass the Noisy USB Power from Your Computer and Replace it with Fresh, Clean Power

Lower Your System's Noise Floor and Increase the Analog Perspective from Computer Audio Files

You've never seen or heard anything like the iFi iUSBPower because there's never been anything like it. The world's quietest USBpower supply, it removes noisy USB power from your computer and replaces it with clean power, eliminating any pollution corrupting your data. Designed to be the best power supply for all audio devices, no matter the price!iUSBPower boasts a Super Regulator purified power supply, the innovative IsoPower connection system, and IsoEarth technology. Use the iUSBPower with any DAC, and the level of sonic improvement you'll hear will be shocking. Pair it with the iFi DAC or any USB DAC in the world, and you'll be in heaven.

"In my nearfield desktop system replacing the stock AC power supply with the iUSBPower lowered the iDAC's already low noise floor to the point where it sounded very much like what I'm used to hearing from a live microphone feed. Micro-dynamics seemed more pronounced when the iUSBPower was attached and the smallest details buried in the mix were easier to hear."
– Steven Stone, The Absolute Sound

Super Regulator Technology Combines Purifying With Filtering
At its core, iUSBPower lowers the noise floor, enhances microdynamics, delivers whisper-quiet soft passages, improves sonic richness, and unearths important musical details. Quieter than a battery, it elevates the vibrancy and lifelikeness of any music you play. Its Super Regulator technology encompasses multi-stage and multi-order power purifying with filtering. An audio-grade USB power-supply unit and incredible voltage accuracy help explain why the iUSBPower supplies the cleanest power ever.

"This has some serious implications for the deluxe music server sector. Why spend $2-3k building a bespoke PC or buying off-the-shelf megabuck servers when a $200 appendage will soothe EMI/RFI nerves on ANY device with a single clunk-click? At that price, EVERY serious digital audiophile should have one. A round of applause, please."
– John Darko, Digital Audio Blog

An Entirely New Way to Connect Your USB Audio Device
More than just a stunningly quiet power supply, iUSBPower offers an entirely new way to connect your USB audio device. Sure, there's the standard USB option. But taking into account the iFi dual-path USB cable, iFi's IsoPower system allows you the opportunity to run separate power and audio data lines - much like you already do with separate interconnects and power cables. IsoPower eliminates any pollution between data and power lines, keeping your USB data free of contamination and removing USB signal noise from power-supply lines. You'll hear your USB devices perform at their maximum ability.

"This was another review where it was mostly all fun from the first to the last notes played through the iFi duo."
– Michael Lavorgna, AudioStream

Reduces Ground Noise by a Factor of 10
Specifically developed for the iUSBPower, IsoEarth breaks the noisy DC ground connection between your computer and your USB audiodevice, further reducing ground noise by a factor of 10! With the iUSBPower, your device will operate in the cleanest-possible environment, affording music to flow through unimpeded and with utmost transparency.

Not an Add-On But an Essential Audio Component
If you're serious about sound, there's no reason not to at least give the iUSBPower a shot in your system. It's 100% Music Direct Money-Back Guaranteed. And it'll have you wondering why it took so long for a manufacturer to come up with its likeness. Thanks, iFi.

iFi Gemini Dual-Headed USB Cable

The Only Cable of its Kind to Fully Separate the Power and Audio Signal

Superb Connectors, Incredible Shielding, Custom-Designed RF Shielding All Standard

Another first from iFi: The progressive manufacturer's Gemini is the only USB cable of its kind that fully separates the power and the audio signal in two cables, netting grain- and edge-free music reproduction. Gemini's special geometry adheres to the 90-ohm impedance specification even better than the USB 2.0 standard. In addition, FINAL USB machined connectors provide stellar end-to-end shielding while custom-designed triple RF silencers provide the widest possible filter range without affecting the USB signal. Sonically, Gemini is the cable you want.

Avoids Interference and Geometry Issues Common to USB Cables
By carrying audio and power in two separate cables, Gemini avoids the interference issues that plague common audiophile USB cables, particularly since power is heavier gauge and audio lines possess more cores - to say nothing of geometry distinctions. In Gemini, power and audio signals are thus individually transferred and free of transmission problems. Your music will sound the way the artists and producers intended.

FINAL USB Connectors Provide Remarkable Shielding
While the fact that signals run through both the cable and the connector is common knowledge, a majority of USB cables cheap out on the connector by using molded plastic covers. But since plastic cannot shield the high frequencies in the USB data link, noise radiates out and sound is compromised. Durability also becomes a troublesome issue. iFi eradicates any such problems by using FINAL USBconnectors that afford superior end-to-end shielding. Machined entirely from solid aluminum and gold plated, they are the new standard in connectors.

Enjoy the Silence 
Outfitted with three custom-made metal oxide ceramic RF noise silencers that cover different effective ranges, Gemini even addresses RF issues - most other cables ignore it. Not only does Gemini broaden the range over which RF noise is silenced, its middle silencer is adjustable in order to "detune" the antennae formed by the cable depending on the system conditions and requirements. None of the wide-range RF silencers affect the USB signal. Enjoy the silence.

Pair With the iFi iUSBPower for the Ultimate in USB Quality
A twin that dares to be different, Gemini attains zenith performance when paired with the iFi iUSBPower power supply, forming a combination that delivers the ultimate in USB audio sound quality. That two compact, budget-priced audio devices can produce such divine results is almost unthinkable. But as iFi keeps proving, anything is possible.

<review from Noble HiFi>

Ifi iUSB - review

Disclaimer: A big thank you to Ifi for providing me with the iUSB Power to review.
If you're a regular visitor to this blog you'll have noticed a few devices from Ifi Audio on here recently. I've been lucky enough to play with almost their entire catalogue, which is especially great considering they work so well together. The iUSB will be the last of the Micro Ifi devices featured, but as you may have seen on the Head-Fi meet article, there are some even smaller portable units on their way that look very exciting indeed. 

The iUSB's purpose is to purify the power supply in sensitive audio equipment (typically USB DACs), removing troublesome noise from the equation. It's design to work with any USB DAC, not just Ifi's own iDAC, but it can also be used in conjunction with the Ifi Gemini for even better results. The fact that these two items are bundled together shows that Ifi sees a benefit to this combination and they are not simply alternatives to the same problem. 
     SOUND
I found the Gemini cable helped clean up the sound quality somewhat, but the difference made by the iUSB was more noticeable. The effect with the iUSB in place is one of less grain and one that sounds cleaner and more clear. It also felt easier to sense finer details and separation seemed better. This will be obvious to some, but also like the Gemini (or any cable upgrade), this is not the same difference as adding a good DAC and amplifier, but it can make an appreciable difference. I say 'can' because it depends on a great many factors. One factor to complicate matters is the background noise of the environment you're listening in, but the two main factors are the power of your source and the DAC being used, the latter because higher end DACs can also use various methods to purify power/signals internally too.

The iUSB is going to be more effective with desktops computers where power comes from the mains and there's so much of it being thrown around that's poorly isolated. Although laptops are much less susceptible to these kind of problems while running purely off of a battery, some issues can still occur when they're charging. Desktop power supply units (PSUs) vary greatly in cost. Some come free with a £30 case and others cost up to £200 on their own. Obviously the quality of their power will vary too, but none are built with high-end audio equipment in mind. You might think that the low voltage (5v) power accompanying a USB cable is innocuous, but the problem is it's not isolated from the rest of the system. This is where the iUSB steps in to save the day. As most people will know battery powered systems suffer from less noise, but the iUSB's noise output is rated even lower than a typical 9v battery, now that's an impressive boast!

     SET UP
The iUSB used in conjunction with the Gemini cable can improve things yet further. Although both the Gemini and iUSB are made to assure the power interferes with the audio processing as little as possible, they go about it in quite a different way. The iUSB aims to purify the power as much as possible, whereas the Gemini tries to solve contamination issue by avoiding it entirely. Depending on how you look at this (or what equipment you have) you can use these two methods in different orders. Ifi recommend the Gemini be used post iUSB for best results, but the way I see it both have their merits. 

• Computer > other USB cable > iUSB > Gemini > USB DAC

The design of the Gemini cable works a bit better this way around, but the other way around seems to make more sense if you're using a USB DAC that's combined with a headphone amplifier, like the iDAC...

• Computer > Gemini > iUSB > other USB cable > iDAC

This makes sense in my head because it keeps the potentially dirty power away from the data until it's re-combined after purification. Of course you're welcome to use it either way around if you so wish. It's nice that the iUSB allows this flexibility, by having the second USB output provide data and power (they will be combined unless you're using the Gemini cable).

Barring cost there's also nothing to stop you using two Gemini cables (one on either side of the iUSB). Even with my new found appreciation of power purification, it's rather difficult to justify this. Since they already work so well apart and together, I find it hard to believe there's much more room for improvement, but to be fair I haven't had the chances to try it yet (since I have only one Gemini here). Ifi did confirm that this would provide the best potential results, so if you're able to afford it by all means give it a go.
     BUILD The iUSB chassis' build and design is consistent with all of the other Ifi Audio Micro devices, so when used with the iDAC and/or iTube etc. you can happily stack them. Ifi will soon be making available a stand to fit up to four Micro devices together. From seeing this at the Head-Fi meet I can say it certainly makes them neater and sexier. 
Like the iTube and iCAN the iUSB uses the same 9v adaptor to provide it's power. Unlike the iTube the power socket of is on the back of the unit, which keeps it neatly out of the way, I just wish all of the USB sockets were also on the back for the same reason.      FINAL WORDS
The iUSB is a power purification device that can used with any USB DAC. It makes even more sense when used to power USB DACs that are combined with headphone amplifiers because that power goes on to directly amplify your sound. Further versatility can be achieved when combining this with the Ifi Gemini cable, which can be used at either end of the iUSB, but that's not to say this isn't a compelling product on it's own. 
Compared to the Gemini I think that the iUSB provides an even stronger benefit in cleaning and improving audio in most cases, even if it's a bit more fiddly to add to some systems. For example: a USB powered DAC and headphone amplifier used with a laptop is very convenient (as it doesn't require any power cables), adding the iUSB to the equation destroys that simplicity somewhat. Being powered the iUSB is obviously reserve for desktop systems and that's no bad thing, it's actually nice that between this and the Gemini there are options for either scenario. 
Something like the iUSB is not as important as choosing the right DAC and amplifier, it won't fundamentally change their sound, but it can purify and hone it to perfection. I noticed and appreciated the difference made by adding it to my desktop systems. It might not be cheap, but this kind of quality never is.