Tried these again last night with my Fiio E11 and a Total Airhead.
Source was a Sansa Clip+ with mostly FLAC and 320kbps files. Using a cheap Cardas cable to the amp.
I noticed on the E11, the sound was a bit more fatiguing. The mids though just were not as forward as they were on the E9 or the Airhead. I would say even less forward than they should be with any amp. Strange.
On the Airhead there was a lot more volume, but I could crank them to 100% without damaging my hearing.
It's nearly impossible to get the clipping/red over-voltage light to blink. It took specific songs and I had to crank the volume to 100%. At around 90% volume it never gives me the blinking red light. I guess that's a good sign.
I think I only managed to find one that would blink for me.
I also found that when not using my HRT DAC it's extremely difficult to tell the difference between headphone and interconnect cables on the Q701, With the Cardas there was a bit of difference, but nothing major.
I still find the Q701 stock cable to be perfectly good and not as bad as most stock cables. I had an ALO SXC cable and currently have a Canare one, but I prefer the stock cable. The Canare is a bit weird.
I imagine the best DIY wire for the Q701 is Mogami and I should try that. Should cost under $20.
BTW if the Airhead when plugged into the Sansa Clip+ is clipping, then I imagine using a Sansa Fuze or Ipod Touch with a LOD cable is a major no-no due to the Q701 getting less power.
Based on memory I never liked the Q701 when used with a LOD cable. Sounded kind of a bit harsh and fatiguing.
Still can't figure out why people think the E9 might be a poor match for these. I used my Q701 in Fallout 3 connected to the E9 and it was just about perfect. I actually think the K601 is better for gaming though
BTW the mid-bass with the HD-600 annoys the heck out of me. I must be the only person on earth who gets annoyed by the mid-bass on the HD-600!! I took that off during Fallout 3 in about 5 minutes.