iFi iUSBPower: Taking the Audioquest Dragonfly DAC Up A Notch
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
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.
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 computerMy 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.