[dsgoen]

In a pinch I've been satisfied with using my Sennheiser HD 800s with the J3. They get quite loud on most recordings and the sound is pretty darn good! So even 300 ohm is okay if you don't want to damage your hearing (Which I did, tinnitus in my left hear, so keep those volumes lower if you plan on getting older!).
 

 

[mertovic]

I have Sennheiser IE80 and Sennheiser HD 598 , 

I want to buy a Cowon J3

Do you think these are a good set with J3 ? I am looking for a good mp3 player
I don't care the harddrive space and photos , videos or some silly property ,
I just need a very good sound quality maybe little design..

 

[Coq de Combat]

Quote:

I have Sennheiser IE80 and Sennheiser HD 598 , 

I want to buy a Cowon J3

Do you think these are a good set with J3 ? I am looking for a good mp3 player
I don't care the harddrive space and photos , videos or some silly property ,
I just need a very good sound quality maybe little design..

The IE80 sounds good with the J3. Though I haven't had the chance to compare the combination to any other than IE80+E10, so take what you will from it.
 
To be honest, there isn't much of a difference between the J3+IE80 and the E10+IE80.