The Fiio e17 is a dac and amp combo put together. What is a dac? A dac is a digital to analogue converter. It's what's responsible for turning digital data into analogue which is what is fed to your headphones. An amplifier boosts the analogue signal to give it more weight, volume and most importantly to properly drive headphones with higher impedances. Most devices nowadays have both a dac and amp, though both are of poor quality. Take the ipod for example. I had an iPod classic 6th gen and it sounded horrendous with any decent headphones. Though the general consumer won't consider the difference with a higher end dac/amp. Most devices can only power low impedance headphones, the standard being 32 ohms. Sound: Definitely the most important part, the sound is more of a natural and warm sound signature which is very consumer friendly. Though, the amp also has the option of a built in equalizer as well as balancing. The built in equalizer does a very good job for those who need it. You can boost the bass or treble, or even reduce either of them. The amp will drive some decently high impedance headphones very well. I find it partners very well with the akg q701 (which I want to buy and is the reason I'm selling my grados). The akg is quite analytical but the fiio e17 is quite warm, giving the akgs what I feel is the best of both worlds. The fiio e17 is a huge improvement over the iphone 4 internal hardware. I tested it with my parents and grandparents and they all said they noticed a dfference. Build: The build is very solid. I'm not worried about it breaking if I drop it. The thickness is a bit more than the iphone 4 but the height is a little bit less and the width is about the same. UI: The user interface is very simple to use. You press menu to go into the menu then the volume buttons to scroll through the menu. Press menu again to make a selection then use the volume buttons to make changes. After, just press the power button to go back. Value: I found this to be a very great purchase for me since the amp/dac combo is very adaptable to different situations. I can use it from my computer through the USB input or through my iphone on the go. Using the equalizer, I can change the sound signature to my liking no matter which pair of headphones I'm using that day. I found the sound quality through this to be a significant improvement so overall I am happy with my purchase. Personal score: 9/10
