I bought this amp as my very first ever headphone amp. I bought it for my Denon AH-D5000 at the time, because even though it is very sensitive and effeiciant, my laptops audio jack still is incapable of outputting proper volume or impact (the internal amp chip must literally be putting out less than 1mW for this to be happening lol). So the E11 became the very first amp I got to hear as a reference point to what amps should sound like. Initially I was quite impressed by the sound, it was loud, the bass was super impactful on my Denons, and overall it felt like I was actually hearing my headphones in the proper way they were meant to be heard. That is until I started comparing the sound quality to my headphones plugged directly into the computer. See at this time I didnt yet have a dac, so whatever the E11 was plugged into was the dac (either my laptop, or my ipod classic). So I was very familiar with what the sound signature is supposed to be with both of my sources. The problem is that after going back and forth between my computer and E11 a few times, I noticed the E11 had a pretty noticeable drop in soundstage size. It was enough of a drop that it actually was becoming unpleasant to listen to music. It felt like the soundstage was a lot smaller than what the headphones were capable of doing (and its not like my headphones are the best at large soundstage to begin with, being closed back, and I wasn't using an external dac). Then when I used the E11 with my ipod I noticed the other major sound quality issue. It made the treble become a bit too sibilant on many more recordings than it should have. I use all lossless, and relatively well mastered music, plus I was familiar with how they sounded playing out of my laptop. So albums that normally sounded just fine, no sibilance at all, just maybe a slight brightness under normal conditions (out of the laptop) now sounded terribly sibilant to the point of being painful to listen. It didnt help that the ipod classic itself is slightly bright sounding, and that the Denons can be a tiny tiny bit too bright in the treble sometimes (usually its not thought, just sharp, but still enjoyable). So after a few weeks to a month of use, I just gave up on using it, because my laptop simply had the superior sound quality, even if it was less powerful and more quiet. I just couldn't enjoy music played through the E11.
Now there are some good aspects of it, and this is why I say It's a decent starter amp. The bass is really nice, pretty tight, lots of impact, and rumble. It has little distortion overall, and the EQ settings as well as the gain settings all work nicely, although I just preferred using it in the default settings, meaning everything on 0 EQ and low gain. Also the volume knob has a nice feel to it, and is pretty good at getting a nice volume level. Also the battery lasts for a very long time. If you only listen for a few hours everyday, then you can easily get a good 2-3 days out of the E11 before actually needing a recharge, but keeping it charged everyday is always useful.
Overall I'd say you pretty much get exactly what you pay for in that price range. Also I don't think the numbers for its output power are correct, because I was able to max out the volume knob with my 25ohm/116dB(around there) headphones without ever really feeling like this was too loud to keep them on my ears. Sure it was super loud and definitely not something you could listen to, but as a drummer I know what 110-130dB of volume sounds and feels like. This amp was not making my super effecient headphones reach those levels very easily. So I'm sure it could drive slightly harder to drive headphones, but I can't say it will do a good job of it in terms of volume. In terms of dynamics and being able to 'control' the drivers of a headphone, that it does pretty well. So I guess if you dont care/dont notice the small soundstage, slight sibilance, hiss, and ok output power, then this makes a pretty good buy for its price. Otherwise I would seriously just save up for something better, once you hit the $100 mark I'm sure theres plenty of much better amps. I bought this amp because of so many good reviews on its sound quality, and im writing this one because I want people to be aware of the potential disappointment this amp can bring if you have never heard or bought a headphone amp before. None of the many other reviews mention these same problems, but they are there.
Now there are some good aspects of it, and this is why I say It's a decent starter amp. The bass is really nice, pretty tight, lots of impact, and rumble. It has little distortion overall, and the EQ settings as well as the gain settings all work nicely, although I just preferred using it in the default settings, meaning everything on 0 EQ and low gain. Also the volume knob has a nice feel to it, and is pretty good at getting a nice volume level. Also the battery lasts for a very long time. If you only listen for a few hours everyday, then you can easily get a good 2-3 days out of the E11 before actually needing a recharge, but keeping it charged everyday is always useful.
Overall I'd say you pretty much get exactly what you pay for in that price range. Also I don't think the numbers for its output power are correct, because I was able to max out the volume knob with my 25ohm/116dB(around there) headphones without ever really feeling like this was too loud to keep them on my ears. Sure it was super loud and definitely not something you could listen to, but as a drummer I know what 110-130dB of volume sounds and feels like. This amp was not making my super effecient headphones reach those levels very easily. So I'm sure it could drive slightly harder to drive headphones, but I can't say it will do a good job of it in terms of volume. In terms of dynamics and being able to 'control' the drivers of a headphone, that it does pretty well. So I guess if you dont care/dont notice the small soundstage, slight sibilance, hiss, and ok output power, then this makes a pretty good buy for its price. Otherwise I would seriously just save up for something better, once you hit the $100 mark I'm sure theres plenty of much better amps. I bought this amp because of so many good reviews on its sound quality, and im writing this one because I want people to be aware of the potential disappointment this amp can bring if you have never heard or bought a headphone amp before. None of the many other reviews mention these same problems, but they are there.