I am thinking about a Hifiman he 400. Will this work well with the O2 and ODAC or the Magi with the dac or is there a better amp/dac in the same price range? If I forgo the amp/dac I can get the he 500. Would that produce better quality music than the he 400 with amp and dac?  I mostly listen to...

I am in the market for closed headphone that would be the best for rock, classical, trance/electronica and the occasional rap/hip hop (in that order of importance) . Not too much bass since it gives me a headache. I am currently learning towards the DT770 pro 80 ohms. I am looking to spend less...