[ShootingStars]

I would not like to upgrade cables or anything else.

The setup will be:
MacBook > E17 > Headphone
iPhone > E17 > Headphone
Walkman > E17 > Headphone
 
Which headphone should I buy? HD598 or HD650?

 

[SuPeRnEwB161]

i would say HD 650 because you wont have the need to upgrade for a long time to come with them. if you got the 598 you may end up getting upgrade-itis and spend way more than you want to on your next set of cans. The 650 also will give allot of headroom for new amps in the future where the 598's have a much lower impedance and wont make sense to run using a good amp anyways. If you are planning to use them for commuting (which would be a little silly with openbacks 

) the easy to drive 598 would be more handy. 
 
it all comes down to preference in the end though.
 
one more note you can sometimes find the 650's used for cheaper than the 598's because they are a bit of an older model. 
 
Good luck!! 

 

[ShootingStars]

I am not considering upgrading after the point though, I am wondering if the E17 can actually drive the 650s

 

[asdfghjkzxcvbnm]

They will drive them but not that well.

 

[ShootingStars]

Would it better to have a HD650 not drive that well or a HD598 instead?

 

[SuPeRnEwB161]

I think in that case the 598 will give you more flexibility for portable use and the 650 may sound like there is something missing with the E17. i think with your amp the 598 will be the better choice if you know for a fact that you will not be upgrading in the future.