Pros: Good Sound Quality, Durable, Small, Decent Battery
Cons: EQ Control, Buttons/Menu
I have been using the E17 "Alpen" every day for over a year now. It is my go-to device for enjoying music at work, or anywhere other than my home office. So, here are my thoughts:
This was the first thing I noticed when I unboxed the device. Brushed metal casing felt very durable, and after this past year of daily use, still looks almost new. I think it looks great.
Controls and Battery Life
The screen on the E17 is most simply stated as utilitarian. It's bright, it works, and it's not going to win any design awards. The buttons are the same. Menu navigation feels a little bit clumsy, but after a week or so, it becomes a non-issue. You are allowed to control volume, bass and treble, gain, channel balance, etc. My biggest complaint here is that the controls take big steps. For example, increasing bass moves 2-4-6, instead of 1-2-3.... The volume control has a similar behavior and can be a little annoying. In spite of those limitations, still very functional.
I like the input flexibility of the device, I primarily use the USB (when leveraging the DAC/AMP combo) or AUX in (for just the AMP).
The battery gets me through 2-3 days of use (using a few hours a day) and still has some life left. I charge it 1-2 times a week, depending on how heavy I use it on battery.
I was looking for a portable device that could be flexible as a DAC/AMP or just an AMP (or even just a DAC!), and sound good doing it. Primarily, I wanted the portable amp for when I had headphones like my Grade SR125s in tow.
My setup on the go sometimes looks like this:
iPhone>Lightning-to-30pin>Fiio 30pin-to-3.5mm>Fiio E17>Grado SR125 (or other HP)
This provides the needed power boost to get the Grado HPs to open up more, and provide body in the lows and mids. I do set the e17 Bass to +2 with these headphones. This setup is exponentially more enjoyable to my ears than attempting iPhone>Grado SR125. Running direct from iPhone to these headphones is a bad idea, and will result in a thin and harsh audio experience.
My other common setup is this:
iPhone>Lightning-to-30pin>Fiio 30pin-to-3.5mm>Fiio E17>Shure SE215
That's right, I amp my highly efficient IEMs at work. Why? Because it sounds better. Maybe that seems crazy to some, and I understand. Technically, the iPhone should have enough juice to power these IEMs (from my limited understanding of the electrical aspects). But to my ears, the SE215s love the E17. There is a marked improvement in clarity, tightness in the bass, and overall exciting feel to the audio. I thought I might be crazy at first, so I A/B'd it off and on for months, and always preferred the E17 in the middle. I never run my SE215s directly to my phone anymore.
My final on-the-go scenario is the following:
MBP>USB>Fiio E17>Grado SR125 (or other HP)
The other two setups use the E17 as an amp only. This uses the E17 as a DAC/AMP. While the MBP has a good DAC already (better than any other laptop I have listened to), I find that this setup sounds better than using the headphone out from the laptop to the aux in on the Fiio E17. Using USB also has a side benefit of charging the E17.
The final (and new) scenario:
Mac Pro>USB>Fiio E17/E09K Combo>Grado SR125 (or other HP)
I've only been using this setup for about 2 weeks with multiple HPs, and my thoughts speak more to the pros and cons of the E09K, so i'll leave it for another review.