Behringer HA6000

It is a very nice headphone amplifier. Sounds good and find lots of use in the studio, especially for life recordings. However there two things to note. The first is the counter-intuitive feature with "balance" knob. The front panel says AUX < > MAIN, so the first thing I did was turning the knob all the way to MAIN. Then there were a couple of hours of struggle, as I only got the sound in one ear. I re-checked all the possible cable combination in order to locate the fault with no luck. I was about to start filing the return. Then I decided to read the manual very carefully and found the note with small font: "when AUX jack is not inserted the balance knob acts as a LEFT-RIGHT balance". Damn it. They should have pointed that out with bold and large font. The other thing is the power. It is pretty much OK with 250 ohm headphones in a rather quiet environment, but I feel that if I am going to record some louder music then I might run into problem of headphone volume being too low...

It does what it's supposed to.
If you are looking to connect up to 6 headphones to the same audio source you can do that with this amp. But you can also use each channel individually. Each Channel has 4 knobs to control the bass, treble, source and level. The knobs feel very smooth and responsive. The overall build quality doesn't feel cheap and is very stable. I didn't have any problems with it so far (about 4 months) and each input and output works.
The sound is decent, but you will hear audible noise at higher levels. You won't hear it through loud music though.
If you are looking for a cheap Headphone amp that will power many headphones, I highly recommend this one.