FiiO Portable Headphone Amplifier

So this is my first portable amp that I have purchased. Prior to this I have used my receiver headphone out, outs from too many mixing consoles to name and my portable champ my iphone. Needless to say that the iphone is the worst out of all that I have used, sounds like booty to honest. First Impression (looks): The amp is tiny. It fits with room to spare in the palm of my hand. The amp has a matte finish from which fingerprints will be attracted to in disgusting ways. The two click buttons that are on there (EQ aka bass and Hi/Lo settings) feel a little cheap. I was actually afraid that I was going to scratch the plastic finish as I have to use my nails to switch anything because of their size. The buttons are tiny and it is hard to tell when you are in the first EQ setting or on the way there. EQ zero and two are easy as they are at their respectable extremes.The volume button is smooth once past the "click" of on. It's made of metal which gives a nice tight smooth grippy feel when turning the volume. This thing weighs 2.3 ounces and I gotta tell you that I thought it shipped without the battery. It is that light. I had to open it to make sure that the battery was actually in there. Sound: Turned the amp on with nothing plugged in and all I heard was the fact that I was plugged into an amp. Being around much more powerful amps it is nice to know that the operating noise that I get from a $6000 QSC amp is the same that I get from a $59 headphone amp. Immediately, I began listening to uncompressed music as the "Garbage In Garbage Out" rule applies more than ever when amps are involved. Ask the off key singers. I used my custom molded UE 5's from Ultimate ears. I will be purchasing the Hifiman HE-500's as this amp is more than capable of pushing them. My UE's have an impedance of 21 ohms which my iPhone can play with not much success. The first thing I noticed is the sound stage. It is much wider than using no amplification. The center feels very focused. Low End (bass) - The amp on EQ setting zero plays music as it was mixed which is typically what you need on a well mixed album such as Bob Marley's orignal mix of Could you be loved. On EQ setting one is where the punch of the low end comes in. Forty hertz from Linkin Parks Numb come through clear enough to rattle my ear drums. It is enough to fill out your needs without blowing you out of the water. The EQ two setting should not be used. The low end seems to remain the same while the low mids (150 - 300) get a boost. The only thing that I found this setting to sound good with is one reggae song. It does not sound bad but does muddy up the sound. Mid - This is where this amp impressed me. Mids that are implemented well are silk on one's skin, like apple filling to your pie if you get my drift. The way this amp pushes the mid levels is truly amazing. I had to keep checking to make sure that this small amp was what was reproducing the sound. I can't say enough about the way that the mids make me feel. GREAT!! High - This is generally where everyone wins or loses in my book. Consider the high end the pie crust to my apple pie. Too much of it, and it takes away from all of the hard work that the low (crust) and the mids (filling) have done. Too little and it gives you a taste yet leaves you wanting for more. I am on the side of not enough on this amp. If it had just an 'nth more I would probably never take this amp off from my headphones. The high end is there not sharp, not dull but could be brighter. Hi/Lo (Outside casing) - Important to note that there are two Hi/Lo gain settings. One on the outside which in my opinion widens the sound stage slightly larger and boosts the mids yet keeps the high end sharp without cutting into your brain. At the same time it would be nice to have a touch more highs to make the sound better rounded. The bass sounds untouched. That being said switching from Lo to Hi does not kill you with POWER!!!! It gently raises the levels without hurting your ears by introducing sharp highs or ear splitting high mids. Good to have but not necessarily that important when on the lo setting (internally). Hi/Lo (Inside Casing) - Also important to note that on the Hi level on the inside that your battery life is cut from ten hours to somewhere around four. All listening prior to this was done using the lo setting. On the high setting the amp sounds so much bigger but not in an obnoxious way. Music of all kinds sound much more full bodied and in your face. The bass boost on EQ 1 is where its at. You have no need to go above this simply because of how growly the low end sounds. Depending on how well the mix you have is kick drums punch you in the face and the mids and highs soothe you. My negatives to take away: Could use more high end, and ACTUAL level two for bass that could punch out your teeth rather than a mid booster. Wish they didn't use plastic that attracted fingerprints. Bigger buttons on the side for the EQ and gain settings. Overall, my opinion on this amp is that it is absolutely AMAZING for the price. Great first amp that has WAY more power than I will ever use (until I get my HE-500's).