I asked this in the Ultrasone forum but found many talk about Ultrasone here, hope it's alright to ask it here as well. If I'm not planning to use amp, will the PRO 900 still be the best Ultrasone for me? My other choice would be the HFI-580, I know these are like two ends of their product...

Hi, I'm pretty new to headphones and planning to get my first Ultrasone, PRO 900 seems to be the best(within my budget), but I might not get to try it so here's my questions: Would it be a waste if I'm not going to use it with an amp? Am I better off getting a HFI-580 if that's how I'm going...