I don't own a pair of HD-650s but I tried them at a Head-Fi meet with my Woo 3 and it was fantastic. I'm always wanting a pair for my Woo 3 as they seem like a match made in heaven.

the hd 650s scale better than the denons and will outperform the denons with a good system.

 

denons are funner but in the end, the 650s are the better headphone. the mids aren't recessed and they're more detailed. however, the hd 650s have less sub-bass, but its cleaner and better controlled than the denon.

 

the hd 650s would be a huge upgrade from the ultrasones. 

 

and a decent amp in the 250-350 price range would work.

 

amps like the WA3 would be great for it, but more expensive.

im a college kid too

 

umm but yeah the e9 would have enough power to drive them. but it won't bring out the full potential of the hd 650s.

 

if you're on a budget now, i guess isn't a bad choice.

theres some on amazon refurbished for about 300 usd.

Just want to mention that HD650 is open back and leak sound, while the Denons er closed and don't leak (though they don't isolate either).

 

Just want to throw this in there, easy to forget when choosing :)

then get hd 650 its easy

In reality the Denons are closed-back that really do leak. Not much in keeping the sound inside. My Wife will tell you, I wake her up at 2:30 am at times.
 

 

I've never woke my gf using these cans. I even used them at the library at school with a friend beside which would alarm me if it leaked any sound.

Maybe we listen at two very different volumes or something