That's excatly what I'm planning to do NOW :D
I will give it another shot. At the same time, my dad's gonna come back to its (my) beloved HE-4 and will decide which one he wishes to keep.
I unlocked his Cowon J3 to full volume (that was his main concern: he could not play loud enough even with +20dB on the M-Stage) so he can drive it loud enough now.
He's no audiophile but he's spot on when he describes the sound of both: one is dark, the other airy ^^