I've been listening to my K240S with my new JDS Labs 18v cmoy and they have never sounded better - even with the E9. This really is a cracking amplifier. It sounds great with these headphones. Quite warm but really gets those drivers working well. The dynamics and seperation ect. have really improved. I really love this combination. These 18v cmoys have loads of power. Even do a decent job with the K601, though I've not tried it with anything other than my ipod yet. Unbelievably I hardly need the volume knob any higher than I do on the E9.
I've also been comparing the K141 mk2 to the K240s and the latter is clearly superior for most music. I think I will keep the K141 for gaming now. Still a nice headphone though. There is something really nice about the K240S. Just does nothing wrong in my book. It might not be the K240 of old but for the price its really good. I keep going back to it despite having a better headphone.