FiiO E11

For a complete in-depth review you can hit my page where I've gone over this in detail.  I just wanted to list the pros and cons above and leave my feedback here with the star ratings so it can be added to everyone else's opinions.  For the record though, I don't think there's a better price/performance portable headphone amplifier on the market.  Just a crazy good value for a rich and powerful sounding amplifier.

http://www.headphonereviewhq.com/reviews/fiio-e11-amplifier-review/

well i have had some cmoys, and a miu diy amp but none come close to this.

i recently recieved some Shure SRH440's and they sound best amped, and this amp pairs beautifly with them as it is very neutral albeit with a slight hint of warmth.

first off build quality:

very small and stylish, with metal casing and plastic body it is light and feels very nice in your hands. the volume knob is fairly tight and has some plastic to protect you from accidently turning the volume up when its in your pocket. blue LED tells you its on, red tells you its charging.

it comes with a mini to mini cable, a silicone strap to attach it to your DAP, and a mini usb cable to charge it. very nice package from Fiio.

battery life is said to be 10 hours, i have not tested it but i have ordered an upgrade battery, any Nokia BL-5B battery will fit, which is a nice feature.

sound:

very neutral with only a slight hint of warmth, i found no channel imbalance at low volumes like with the cmoys and DIY amp. if you just want more power to your headphones then this is the amp for you. it doesnt add or take anything away from your music. the soundstage is average i think (slightly wider than normal but nothing spectacular)

bass boost:

the bass boost is a very nice feature, as it doesnt cause bleed into the mids, its impact is mainly on the sub-bass region, which is good. with the Shures its nice to have a little bass boost sometimes. it wont make your headphones bass slam but you will hear more sub-bass,

High power/low power - High gain/low gain

i use this on low power and low gain and at volume level 2 is sufficiently loud for most use. (the voulume goes up to 8) so i think this amp will power most headphones with dignity,

This amp is amazing for the price, the only downside i think is that the headphone output jack becomes loose over time.

another great product from Fiio, i am very pleased with this amp. i would highly reccomend it,

sorry this review was written in a hurry.

Quality - In terms of amp build quality, the unit is made up of metal and plastic which isn't really a bad thing. It makes the unit light yet very sturdy. The fit and finish of the metal covers are excellent, very tight and does not move around or jiggle when installed onto the unit. The only gripe I have about is the quality of the battery included in the package. They could have easily stuck in a 1500 mAh instead of the 800 mAh unit inside. Nevertheless, I can easily go to my local cell phone dealer and look for a higher capacity battery of the same spec and replace it myself for a little less than $10. If it wasn't for the added cost of upgrading the battery as well as it's shortish (14+ hours) life, the quality would have been given full marks.

Design - The black covers of the amp are made of metal while the body or chassis itself is made of plastic. The plastic is given a faux aluminum look, and it pulls it off nicely. The color combination of black and aluminum comes off very well. The switches are well thought out as they are easily set but not to the point where it will accidentally be moved when placed in your pocket. Another great design is the protective brace around the volume knob, this actually also ensures that the knob does not move (no sudden volume changes when mobile) when your lugging it around in your pocket. At the same time it protects it from being damaged, since having a simple knob on top would lead it to flex left to right or up and down when in your pocket. The use of a cell phone battery is also a great design choice, it gives the flexibility of actually re-placing (all you need is to buy a cheap spare) and even upgrading the battery unit itself.

Audio Quality - I actually purchased these together with my Sennheiser HD518, I was dead set on picking up the E7 since I was interested with its DAC function and future upgrade factor with the E9 combo. After listening to both amps I was blown away by the robust, full and warm sounds that the E11 amp produced versus the E7. This unit is actually very powerful for its size and price, it has two settings inside the unit itself, low and high power plus an additional setting (outside the unit) of low and high gain as well as two levels of EQ boost. With my HD518 I have it set to high power, low gain and an EQ boost of 1. The amp makes the bass of my HP tighter, fuller and richer while not diluting the mids or the highs. Soundstage is broadened by a bit and overall sound produced is warm.

Value - The E11 would have been given full marks if it wasn't for the weakish battery included in the package, resulting in an additional (yet cheap) cost to upgrade. For the price I would definitely recommend this great portable amp to anyone. Another reason for lowering the overall value is with the L9 cable any iPod is drained of its battery faster, thus limiting the time spent listening to music. Of course a simple remedy would be to use an L2 cable (included in package).

Overall - The E11 is an audiophiles (entry to mid level) portable dream amp! It's cheap and delivers outstanding sound! 

NOTE - Best settings for the FIIO E11:

1) Warmer Sound with Bass - High Power / Low Gain / 2 EQ (1 EQ if you want less bass)

2) Clear Mids and Highs with some Bass - Low Power / High gain / 2 EQ (1 EQ if you want less bass)

3) Max sound - High Power / High gain / 2 EQ

I personally prefer setting #1, since setting it at low gain actually reduces any 'hissing' noise. This setting also makex the sound stage well rounded and the tone warmer overall.

Removed.