Pros: Fairly flat sound signature, price/performance ratio
Cons: Slight hissing with sensitive IEMs, UI isn't the prettiest
First of all, I must thank Bowei006 for lending me the E07k. I won't be going into the sound quality all that much in this review, but will instead go over the physical characteristics of the E07k.
The overall design of the E07k is very refined. It looks better than both the E7 and E11, which I have owned at one point or another.
The front of the E07k is mostly glass, with a snazzy bezel, and piece of metal running along the bottom.
At the bottom is a mini USB-in as well as a line in, and Fiio's proprietary line out, which can be used with the E09k as well as the L7, for a DAC line out.
At the top are two headphone jacks, which is a very nice feature that I've actually used a few times already. It's great for bus rides where you have two people listening to the same song or trying to watch a movie together.
On the right side is a lock switch, which is another great inclusion on Fiio's part.
Then on the right side, we have the volume buttons, as well as a menu and Power/Exit button:
Fiio had another great idea with the volume buttons, which is that it takes to clicks to change the volume, preventing you from accidentally bumping the volume buttons while wearing IEMs and blowing your ears out.
A Quick Note:
I found that the size of the E07k was perfect with the iPod Classic. Using the GR07 and the L9 cable, the top of the right angle GR07 cable matched up perfectly with the top of my iPod, while the bottom of the L9 was level on both the E07k and the Classic.
The overall UI of the DAC is still very basic, like it was in the E7. It controls the volume, channel balance, gain level, and other settings, such as a sleep mode, and the option to change how long the screen stays on after a button is pressed. The Orange menu bar really isn't to my liking, I believe it would look much better in a blue that matched the LED, but this is just my opinion.
Sound: (Objectivists look away now)
As I said before, I won't be diving into the sound aspects of the E07k too much, both because I don't have very much equipment to compare it to, and because I am unable to do proper volume matching, which I believe might be skewing my opinions. Nonetheless, here goes.
My "reference equipment" if you will, is an iPod classic 6th generation, and an objective 2 amplifier. I was able to compare DACs fairly straight across, and I believe that there are subtle differences in the vocals between the Cirrus DAC in the iPod and the Wolfson, the vocals felt more intimate, while being slightly more edgy and harsh. The Cirrus felt smoother, but less intimate. I wouldn't say one is completely better than the other, they're simply different.
As for the amp section, I used the iPod as the DAC plugged into the line in on both the O2 and the E07k. I found the E07k to be ever so slightly rolled off in the treble, making it sound a bit warmer. Overall however, the differences are very small.
Power and Other Thoughts:
-Keep in mind that I generally listen to music between 75 and 85dB, which is considered "quiet", which may mean that the E07K might not be able to power your favorite headphone at 100dB, or however loud you listen-
While the E07k isn't a nuclear power plant, it has plenty of power to drive most, if not all dynamic driver headphones. The HD600s are no match for the E07k, as I can easily drive them to listenable levels at around 20 out of 60 volume points on the lowest gain. Surprisingly, the E07k is also capable of driving my Mad Dog T50RPs at around 25/60 volume points. Personally, even when conducting my brief A/B tests with the O2, there was very little audible difference in sound quality between the two.
One of the problems with the E07k that the E11 also has trouble with is noise. With a quiet background, I was able to hear hiss with the GR07s that was not audible on the O2. However, if you're out on the go (where this unit is really meant to be used anyway) the noise should be mostly inaudible.
I hope you all enjoyed this review, and I plan on adding more to it in the near future. Please leave a comment if you have any questions!