@DFKT - driving fine and driving without the psychological barrier of pushing the volume up high are two different things. The earphones ARE driven fine with the J3, but it's like watching the petrol tank on a 1/4 - you will still get to your home that is only 2K away as well as you would if the tank was full, but you will do it with worry.
People who have really tested earphones at the same volumes on players that still have headroom high in the volume scale versus amps will know that it isn't a quality problem. But, that doesn't affect the major user here. The major user will feel the walls growing in toward them as they push the volume up.
To the church: Sound pressure is the same from an amp or from a DAP at the same volume level. You won't experience one 'better' than another unless the earphone is hard to drive in realistic, physical barriers such as impedance induced distortion/roll off/channel narrowing. 150Ω earphones are a psychological barrier, but are driven well from most sources - you shouldn't need an amp unless you cannot hear them. Pushing volume of 150Ω phones to 80-90% with a DAP does not reduce the quality of the output versus an amp at the same volume level - other than signature differences, a good DAP like a J3 should handle the phones every bit as well.
Now, if you like more warmth, or more distortion, or narrower channel, or more hiss, or... whatever, then by all means buy an amp.
I think a lot of people would be surprised by plugging their 600Ω Beyers to volume-matched neutral outputs, one a powerful home amp that costs 1000$, and the other an iPod or Cowon.
@DFKT - keep up the good fight, but it is a slow death, my friend.
Your car analogy and the psychological factors involved were well explained.
