Leben CS300XS playing with no load? No problem according to Leben customer support when I asked
. Assuring to know you can swap headphones without having to turn it off :-)
"It is no problem to power on without connecting speakers or headphone."
Jude seems to hold the Abyss quite high on certain parameters.Might interest you reading him testing the Ragnarok with HE6 and AbyssNew Schiit! Ragnarok and Yggdrasil - Page 113 http://www.head-fi.org/t/667711/new-schiit-ragnarok-and-yggdrasil/1680#post_10525684
Ihaven't heard the Abyss, but I must say that M9 and HE6 sounds like what many would describe as end game performance - and at a very competitive price indeed :) I see you have a F5 clone for your HE6 - have you heard the M9 with HE6?