Hi Quaresma. I 've read your post and I felt obligated to post:
Don't buy another amp, just buy the HD-449 instead. This is the model you should go with from the start.
I own both HD-439 and HD-449. The 439 has less tremble, less mids, they produce a warmer sound (due to those things possibly) and give more bass to songs that lack bass compared to 449. The 449 however, give better quality bass to tracks with deep bass than the 439.
Since the 439 gave you "too much bass", you should go with 449 which never overemphasize the bass. They produce much better sound than 439 in general (it is quite audible, not just theoretically from the specs) and never too much bass. Don't get me wrong, they do have bass, just not a booming one, especially in less bassy tracks. In those, it just seem to be lacking bass, while the 439 doesn't seem to have this problem. But this is perhaps the only thing the 439 outperform the 449.
From your sayings, I get the feeling that the music you listen to goes much better with the 449, the better highs will give you a more balanced (and definitely more detailed) sound.
Hope this helps ;)
Edited by pouskidis - 12/31/12 at 9:59pm