S/N: 19714 (Made in Austria)
I had a very early pair and it had this awful lower treble peak that drove my ears bonkers. I don't know if it was just bad synergy or what.
I think so.
This is the only headphone i'd never ever sell.
This is the one headphone that seems to throw a fit with portable amps. Even my Q701 does fine with my Total Airhead, but not this so much.
I can crank the volume on my Airhead to 70% and it clips (blinking red light). That never happens on any other headphone. The Airhead even sounds good with my 600 ohm Sextett, but doesn't have enough volume for classical music sometimes.
This is also with power from my player. If you use a LOD cable, it's totally not going to work out well. I find the Q701 is horrible with most portable amps and a LOD cable. My E11 can only drive it (and sound good) if I use the headphone out.
Best amp I've heard with the K601 is the Headroom Micro Amp. With that and the HRT MSII it's just about perfect to my ears. I hated the K601 with the Asgard. I don't know if it's lack of power or what. Asgard is nice with my HD-600 though.