Here's some weird thing to think about though...
I remember years and years ago trying to use my first K701 with a Total Airhead. I was kind of clueless, but it DID yet the job done.
The thing is though that the over voltage light would CONSTANTLY go off. Even when it wasn't all that loud. Drove me nuts.
On my Q701 I can crank the Airhead nearly full blast without it even doing the over-voltage red blink. Fresh batteries too.
My idea is that the Airhead has probably changed a bit since then. Doubt it though. This is my 2nd Airhead amp.
If they made any changes to the design of the Q701, there is a tiny chance it could be maybe say 1% easier to drive. By this I mean really that it just will get louder much easier. Not exactly easier to drive.
I first noticed similar things when modding various headphones and converting them from closed to open.
When I tried a DHC cable on the Q701 I found it weird how when I switched to it from stock it's as if someone increased my volume. Not sure the technical reason behind this, but it's the first time I ever heard this. Probably my imagination.
One last thing...I also find the latest HD-650's much easier to drive than the older versions. Same driver and everything. Wonder why? I was kind of shocked at how well my Airhead could drive the silver screened HD-650. Sounded very good too!
BTW for the TLDR people..I DID NOT say the Q701 is easier to drive