JakeDaBeastYes they definitely need an amp, your choice, doesn't need to be something really expensive. Personally use Schiit Vali 2, powers it very well.
JakeDaBeastthey don't need an amp but to get the full volume, the only thing needed is something to that outputs the recommended voltage or something close to it
JakeDaBeastDo they NEED one? Right now I'm listening to (Beach Boys, Billy Joel, Crosby Stills Nash and Young) pop music genre with the K7XX's plugged into an iphone nano (gen 7) with the volume set just past the mid point. Now if I were listening to classical tunes they might be hard pressed to give satisfaction but still... it can be done without an amp. All the same, I do use a Schiit Jotunheim too that lets me listen to anything with power to spare.
mwr2700Do you notice a difference between the Jotenheim and the phone? The amp section in your phone doesn't have a flat output. The impedance at the output might also be less than ideal for a pair of full size cans. The output my Note 3 sucks ass so I have to find iems that are a good match that can get be through a gym workout. I would never DREAM of plugging in a pair of real headphones into my Note.
Assimilator702oops, my bad, that should read ipod nano, not iphone. mea culpa.
You make good points Assimilator702. However, without knowing the personal situation of the original poster, such as what audio equipment he has, nobody can respond to HIS situation. But to the general question "Do you NEED an amp with these?" No. Do they sound better with one? Sure.
mwr2700The output on my iPad Air2 is pretty good. For watching YouTube clips it does a good job with my low Z Sennheiser HD205 and improves slightly with a Fiio A1. Now those same clips through my Schiit stack and the same headphones is a bump up in resolution. So the Apple outputs might not be as bad as the Samsung's but I would never listen to anything other than YouTube clips.