iFi iUSBPower: Taking the Audioquest Dragonfly DAC Up A Notch

Device Type: USB DAC Power Supply
Input: USB (B-type)
Output: USB Power Only (A-type), USB Power + Audio (A-type)
Output Voltage: 5V±0.5%
Output Current: 1A
Output Noise: 0.1uV (0.0000001V)
Dimensions (H x W x D): 28mm x 68mm x 158mm
Weight: 0.43 lbs
Availability: online direct from Avatar Acoustics
Price: $199.00
Website: www.ifi-audio.com

iFi iUSBPower
My desktop setup has evolved into an iMac running Audirvana, the Audioquest Dragonfly USB DAC, AudioQuest Victoria cable, into the ADAM A3X powered speakers. I listen to this setup every day more and less and I enjoy it every time I listen to it. While it's not perfect, nothing is in hi-fi except enjoyment and as I said, this setup works in that regard for me. So why mess with enjoyment?

I brought home the iFi iDAC and iUSBPower in my suitcase from RMAF which is just one of the benefits of reviewing small light weight things. iFi is a new line of electronics, "with trickle-down technology licensed from AMR and aimed primarily at the future, Computer Audio generation..." The current Micro line includes the iDAC ($299), iUSBPower ($199), iCan headphone amp ($249), and iPhono MM/MC phono preamp ($399). Each micro unit is the same size so they get to share the same chassis which helps save on costs.

Due to our nearly 2 weeks without power, my review schedule has backed up but I intend to get to the iFi iDAC within a few weeks where I'll talk more about iFi and the iUSBPower. But I kept staring at the iUSBPower and wondering—I wonder if it will improve the sound of my desktop system? After all, USB bus power can be fraught with computer-induced noise and if some noise was getting through my Dragonfly, the only way I'd know it is to remove it. Which is what the iFi iUSBPower is supposed to do. Since I had one here, why not give a try?

Absence Makes the Heart Grow Fonder
From the iFi website:

To create a USB power supply that is ultra-quiet is an engineering feat in its own right. We went several steps further. The Super Regulator technology encompasses; multi-stage and multi-order power purifying with filtering. We even commissioned a special, audio-grade USB power supply unit. The iUSB with an excellent voltage accuracy of 0.5% is even quieter than a 9V dry cell battery.

To put it into perspective, if the DC power supply voltage from the iUSBPower was taken as equivalent to the sound level of a large calibre gun fired right next to you (painfully loud, usually taken as around 140dB), the noise produced by the iUSBPower would be completely inaudible to the human ear.

image courtesy of iFi

So the basic idea is the iUSBPower acts as a filter between your noisy computer and your USB DAC. Using the iUSBPower is a breeze. Just connect your USB DAC to the iUSBPower's USB Output, connect your computer to the USB Input, plug it in, and things should become silenter. There are two USB Type-A outputs—"Power only" and "Power + Audio". The former is to be used with an optional iFi "twin-headed USB cable only" which I do not have so I connected to the Power + Audio output with an AudioQuest Carbon USB cable. There's also a switch on the input side to engage the "IsoEarth ground noise elimination system". From the included instruction sheet:

Tip: For the best performance, engage the IsoEarth system whenever possible. Only disable the IsoEarth system when your USB device has trouble communicating with the computer
My setup worked fine with IsoEarth engaged but I did not notice a difference with it in or out. Now, even without the iUSBPower, things are silent in my desktop system but the differences I heard with music playing weren't. And these differences were not restricted to just one aspect of performance. Rather they were wide spread.

The first change I noticed with the iUSBPower in my desktop system was a greater sense of dynamics and transient attack. Guitar strings had more ring, and sounds seemed to come from a quieter, more distant place. There was also greater separation between sound sources making it much easier to follow a bass line or backing vocal. Bass response was also improved and became more distinct and tuneful. Complex passages were much easier to unravel and the entire sonic picture opened up (I wanted to say blossomed but that may be too corny). Vocals sounded fuller and ever so slightly more dimensional.

All of these things add up to a more musically engaging experience. Everything sounds more natural, more fluid, less digital with the iUSBPower. Music becomes more capable of startling with sound which is what its supposed to do. And I want to stress we're not talking about some audiophile obsession with sound effects, we're talking about an obsession with the sound of music. Perhaps a subtle distinction but one worth making.

You may be thinking, You've nearly doubled the cost of the AudioQuest Dragonfly! Why not just buy a better DAC for the combined cost of $450? And you'd have a point but the thing is I like the sonic signature of the Dragonfly DAC especially with my ADAM A3Xs and the iUSBPower does not change this signature it just makes it better.

Better is Better
This is one of the things about caring about the quality of your experience—when better comes along its hard to go back. While I was perfectly content without the iFi iUSBPower in my desktop system, I am even more content with it in my system. I will be talking more about the iUSBPower in my review of the iFi iDac but I thought it worth giving you this quickie look since its benefits are readily apparent. What's more important is the iUSBPower makes listening to music through my desktop system even better. And that makes me smile.

I will note that the effectiveness of the iUSBPower will certainly vary from DAC to DAC and system to system, and its effectiveness and perceived value will vary from listener to listener. That said, I'd be willing to bet that most USB bus-powered devices will benefit from the iFi iUSBPower.

Associated Equipment

Jaron M.'s picture

I'm going to go out on a limb and say that they're trying to profit from the "i".. thing. that Apple pretty much invented. No big deal. A bunch of companies do. I am getting a bit tired of it though. That said, I'd also assume anyone with a Macbook Pro would more than likely use the optical output from their laptop insted of USB. Putting these two things together, doesn't make much sense. Yes, it's all branding mumbo-jumbo but still. I think people would get my point.

I thought the whole deal with an external DAC was to bypass all the "noise" inside a person's computer system. If the DAC is USB powered, I'm having trouble figuring out the point of this device. Is it to give the 5v from the USB more juice?

If to your ears, your music sounds better, then awesome-sauce to you. I just think I'll spend my money elsewhere.

Michael Lavorgna's picture

...is for people with USB DACs like the AudioQuest Dragonfly.

That said, I'd also assume anyone with a Macbook Pro would more than likely use the optical output from their laptop insted of USB.

The optical output of the MacBook Pro is limited to 24/96 so anyone interested in higher sample rates and DSD will, necessarily, use USB.

I just think I'll spend my money elsewhere.

That is one of the wonderful things about our hobby - we are free to spend our money where we choose.

Jaron M.'s picture

..thanks for the info!. 

"The optical output of the MacBook Pro is limited to 24/96 so anyone interested in higher sample rates and DSD will, necessarily, use USB."

I wasn't aware of this. Not sure why, but I always thought DSD and anything over 24/96 had to be used with SPDIF. I'm certinally glad I'm wrong!


Jriden's picture

Hey Michael,

Lest we forget -- the Dragonfly apparently downsamples everything above 24/96 down to 24/96 anyway.  From the AudioQuest website:


"DragonFly can accept audio and music files ranging from MP3s and CD-standard 16-bit/44kHz to native 24-bit/96kHz high-resolution, regardless of music file format."

And from the Dragonfly Brochure:

DragonFly plays all music files, from MP3s 
all the way up to 24-bit/192kHz high-resolution 
music files. 24-bit/176.4kHz and 24-bit/192kHz files 
are neatly halved by the source computer and 
processed by DragonFly as appropriate at either 
24-bits/88.2kHz or 24-bit/96kHz.

I don't know what the heck are they talking about with the source computer "neatly halving" the higher res file formats.  I don't believe my MacBook Pro is doing that.

So maybe that optical output is not such a bad thing after all? 


Michael Lavorgna's picture

The Dragonfly is a 24/96 device but my point was in response to the comment regarding the Toslink output of the Mac which is limited to 24/96 whereas the USB output is not.

firedog55's picture

Wonder how this sounds compared to using a SoTM USB card?

The SoTM card also cleans up power, but has its own clocks.

Frederick Crane's picture

Hi Michael,

I'm looking forward to receiving my first Ifi shipment next week.  After growing up in a family of working musicians, and glazing over the eyes of friends, colleagues, and loved ones talking about things audio, I've left a perfectly engaging career in real estate and development to open an audio salon.  I'll be selling a few desktop solutions via the internet prior to the shop opening in Spring of next year.  Hope you'll make it up to Cambridge to visit.  The web site will be up next week and our ads will commence shortly thereafter.

This is seriously fun,

Fred Crane


Michael Lavorgna's picture

It has been a while.

...I've left a perfectly engaging career in real estate and development to open an audio salon.

Congratulations! and best of luck. If I'm up your way I will definitely stop in for a listen.


burnspbesq's picture

Have you tried them together?

Audible improvement?

selarom's picture

Hello Mike,


You know, now that you've reported how much of an improvement it has made on the Dragonfly DAC, I wonder if it would do the same for a DAC that has its own power source like the Mytek, etc. Will you report on it on your full review?

The idea of the iUSBPower seems to be related to just the power supply to have the DAC running and not including the electrical power of the audio carrying signal, but this has made me curious. Does it filter both, power AND data?? I would otherwise look at this thing as a very high quality powered USB hub with only one port instead of four or six.



Michael Lavorgna's picture

I will certainly try the iUSBPower with a number of DACs and it may make sense to cover this in a separate review from the iDAC. Hmm.

jneber's picture


It would be great to see a review of the USB p/s with a USB to SPDIF converter such as Musical Fidelity vLink, etc.

Keep up the good work on this site! Interview with Gordon Rankin was most interesting. Can't wait to see where his next products will be taking this hobby.


funambulistic's picture

I am sure the iFi USBPower has a lot of technological goodies up its aluminum sleeve, but I wonder if one can get similar results using a powered USB hub. I use a NuForce uDAC at work connected to a throw-away hub (not powered) along with my iPhone, flash drive (sorry, no Apple-esque nomenclature) and, usually, my e-cigarette battery. When the uDAC does not get enough voltage, it tends to heat up (this, according to the manufacturer) and its ibody temperature throughout the day fluctuates greatly. This alone has piqued my interest in the iFi unit (along with the possibility of better sound) but my pocketbook would object. Saw some cheap-o's on Amazon - maybe worth an experiment, if only to save my DAC's internals...

jrebman's picture



Do you think something like this would work well (for a stationary, not mobile setup) between an iPad Mini with CCK and the DAC HD?


I'd love to scale down my nightstand headphone rig and just have the tablet, the dac hd and a nice battery powered amp.






gjc11028's picture

did you experiment at all with different usb cords to see how much they mattered going to and from the device?  thanks



Wilderness's picture

I  just purchased a Dragonfly DAC and now I am curious about the iFi USB power device.  I am assuming that this iFi device can be connected as follows:

Plug in the iFi device to a good USB port on the computer via a USB cable, which supplies both the data and the power to the iFi device.

Is that correct, or must the iFi device's separate power supply also be used?


Michael Lavorgna's picture

...gets its power from the 9V plug that plugs into a wall outlet, not from USB.

dw's picture

Michael, in a few days my Mytek will arrive to replace a Benchmark Dac1 + Halide SPDIF Bridge.  Running Channel D Pure Music on a dedicated MacBook Pro and the flac and other files are stored on a 1TB external Iomega HD which has its own separate power supply via wall wart. To keep things apart ( supposedly the best way ) I intend connecting the Mytek to Mac via Firewire and the Mac to Iomega via USB.  The present setup is the other way round because the Halide Bridge is USB, of course. Now, I have heard that these types of external HD with separate power supplies, inject a lot of noise into the Mac and from there into the Dac and thereby affect the audio out result.  Not knowing if this is corrct or not, my question is : Do you think placing the iUSB between the Mac and Iomega is a worthwhile idea or a silly waste of $$$ ?  Any advice much appreciated.  Many Thanks.

Michael Lavorgna's picture

I did not try the iUSBPower with an external hard drive because I use a NAS so I cannot offer any first hand experience. My suggestion would be to get your new gear and listen to it and enjoy it for a while. If after a few months you still think you'd like to try the iUSBPower, it certainly couldn't hurt.

highstream's picture

Thinking of a desktop application, i.e., computer to DAC to powered speakers (e.g., Audioengine, PSB, Emotiva), is there really much of an audible difference between using the two outputs with IFi's dual-headed cable vs. a single combined output, given that it's recombining on the DAC end?  

Do look forward to hearing how this unit works with other DACs.  I have an Audioengine D1, which I'm reluctant to give up because of its volume knob given the price point (and I got the D1 at 25% off on a mass buy).  Thanks,

Michael Lavorgna's picture

So I cannot offer an opinion on its performance. Yet....

highstream's picture

If you get a chance, a comparison to the Aubisque USB filter would be worthwhile - http://ultrafi.biz/aubisque-usb-filter.html.  The latter has the advantage of installing inline, i.e., taking the cable from the computer on one side (USB A) and then plugging directly into the DAC on the other.  

There's also the Firestone Audio GreenKey USB Isolator at half the price of these two, but it also requires a second cable.

Angular Mo's picture

1. Desktop use; Apple MacBook Pro with optical out (S/PDIF)

is the iUSB something I should use in the path between the MacBook Pro and my Schiit BiFrost DAC?  



2.  Transportable use; HRT iStreamer - an iDevice DAC

this needs a power supply, and I am currently using a DigiPower power pack battery.


is the iUSB a device that I would use to replace the DigiPower power pack?


thank you for the help,