Here's the current sate of my gear:
- The K702's are new but have about 400 hours on them
- The HD650's are older and been used for over 8 months (donated by a friend) - a LOT of hours
- HifiMAN EF2 Amp - about 150+ hours of burn in. 50+ hours with replacement Sylvania 6AK5 NOS matched tubes
My opinions after listening to both headphones
K702's
The good: To my ear these are amazing for a sub $280 headphone - simply fantastic for classical, vocal, jazz and certain rock pieces. I found time and time again that it revealed the losses in my 192K AAC recordings (esp. classical) - switching to lossless recordings of the same pieces took my breath away
on a couple of pieces e.g. Miles Davis, Scheherazade, Dire Straits, Suzanne Vega. I found I can listen for extended periods without getting tired. For my ears the soundstage is very good, the reproduction excellent and the bass accurate and deep. The accruacy is amazing, I particularly liked hearing people's hands rubbing over their instruments on some of my Indian tubla recordings and hearing vocalists breath.
The bad: When listening to dance tracks and techno they are almost too accurate - the bass simply does not envelop you (like the HD650's) that I feel you need to enjoy this music. It is not to say that there is not enough bass, its just kinda over before you get to appreciate it - thus to my ears I think there are better headphones for listening to that type of music. Build quality not as good as the HD650's, but much better then the Grado's I have owned, headband on K702's are more stiff (but they probably need more break in).
HD650
The good: I really, really enjoyed listening to Techo and Dance tracks on these cans. The music just came ALIVE
on these cans (Cool World - was just fantastic on the HD650's). I found I was just cranking the volume a lot on these cans and having a blast. When listening to new age and classical I found that they were very warm - warmer to my ears then the K702's. Overall they are a good as a general listening headphone, they are very comfortable and have excellent build quality.
The bad: When listening to classical, vocal and jazz pieces I found the sound much more "muffled" when compared to the K702's. Especially the bass when compared to the K702's! I could not tell as much of a difference between my 192K ACC recordings when compared to lossless on these cans like I could on my K702's - is HD 650 not as accurate maybe?
Conclusion:
I use the K702's all day (8-10 hours sometimes) and I love the sound - I do not get tired like I did with my old Grado 225 or even the HD650 If I could only buy one pair these would be the one's I would recommend.
As for the HD650's they are very good (but also $100 more), to my ear, good for dance/techno and general purpose listening. I do not find them as accurate and after extended listening periods 6+ hours I grew a little tried. I'm not sure they are worth the extra $100 unless I primarily listened to dance/techno and rock.
As it stands I think for my sub $500 investment on the amp and K702's, I have the best sound to my ears
- techno/dance is a little disappointing, but only because the HD650's rock these genre's and I happen to have them sitting next to my K702's. If I wanted better sound, I would not get the HD650's but frankly look at the next level up of headphone/Amp combination - yes I know its more money, but thats why we all work so hard - right?
