You may find this crazy but I'm sitting here comparing the Q701 to the HD-598. I really do think AKG might have improved the stock cable (over the K702). I've noticed that with my setup and stock cable it sounds nearly as warm as my recabled HD-598?! Not quite, but close. Even on the E9 with the same cables it has a similar sound. Everything is very full sounding and well textured. Not even remotely thin or lacking. I switched to a different cable (plain old copper) and it sounds much different. HD-598 is fairly warm and not as warm as the HD-600, but pretty close.
Right now I'm using the HRT Music Streamer II to my Headroom Micro Amp using a Monoprice Cable interconnect cable. Don't ask me why, but this cable is good for the Q701. I think the stock AKG Q701 cable is really quite good! Not sure why this is.
If anyone is curious, IMO the Q701 has more detail, a clearer sound and a slightly more accurate soundstage. When comparing the size with a good recording, the size often seems the same. Both with a good recording make it seem like there's stuff coming from outside my headphone. I think the Q701 is technically better, but you can't go wrong with either and it all comes down to preference. The HD-598 is much smoother sounding (not by much) and more forgiving though. The treble on the Q701 never bothers me as long as it's not due to the recording. HD-598 definitely isn't as forgiving as the HD-650 though IMO.
I checked on the K240 Studio cable and it looks like it has the same part # as the K702 cable except for one missing zero at the end. I'm going to connect it to my Q701 and see if there's any difference. For you cable haters, it could be that the K240 Studio cable is just thinner if it IS any different. Maybe the Q701 cable has a higher capacitance like the Canare cable? It actually sounds like Canare wire (yes, I know wire isn't supposed to sound like anything). Canare wire on the K702 SHOULD tame the highs slightly too. Don't remember testing that experiment and with short cable length it probably doesn't matter. It always did seem like Canare rolled off the highs on any headphone.
For fun, someone can try the Q701 cable on their K702
EDIT:
BTW I'm surprised how good these sound straight out of my Total Airhead portable amp! I have the volume cranked up on bass heavy songs and no clipping and that red over-voltage light. Pretty nice! Too bad more portable amps didn't have the red blinker. I remember the K701 always giving me the red blink of death on my Airhead. With the K601 it's always going off. Same with the Sextett, but who's dumb enough to use a 600 ohm headphone with a portable amp!
I also noticed that when I had the DHC copper cable, it's like someone had turned up my volume when I connected it when using the same amp volume setting. Guess there's a technical reason behind this, but I forget.
Q701 seems twice as fatiguing when way under-amped too. Anyone notice that?