Yeah, using the K601 from an Ipod Touch is a big mistake. Doesn't sound good at all. The K601 is one of the harder to drive headphones. A little harder to drive than my Q701, but not as bad as the K501. On my Micro Amp on high gain, the K601 needs to be about 10-15% higher than that of my Q701.
I actually use my Q701 unamped sometimes (from an Ipod Touch), but that's just for ambient music.
The E9 can drive the K601, but I think for the K601 and Q701, they really need better amps to be at their best. If that wasn't bad enough, they require good synergy. I've had a few amps that made the K702 sound bad.
It seems some people say the E10 can drive the Q701 and even the K400. That's a huge surprise and i'll need to try that! If it's true, that's pretty impressive.
My Total Airhead can drive the Q701, but gives me the red blink during songs with lots of bass or if the volume is up too high.