[Me x3]

The Asgard 2 is a very neutral amplifier, slightly mid-centric and 'musical' next to splashier sounding or overly analytic SS amplifiers, but overall a very neutral amp.
If you like the sound of the HD700 best chances are you'll like it even better with the Asgard 2 since it adds some refinement and space to the sound.
 
On the other hand if you really want to tweak the sound of HD700 the Asgard 2 won't do that for you, sibilance will be there if it's on the recording, compressed music will sound compressed, shouty upper midrange will sound shouty and so on... Maybe a Lyr 2 might serve you better if you want to tweak the sound because you can go an find the darkest tubes if you feel the need.
 
That said, you should know that differences among amplifiers are smaller than diffrences among headphones. No amp will make the HD700 sound like HD650 or LCD-2.
Picking the best headphone according to your preferences, then looking for an amplifier is most of the times the shortest path to satisfaction.
 
HD700 is a good headphone in my book, full of strenghts but it rules out some recordings due to its tuning.
Pick the right recordings and it willl sound great, pick the wrong ones and you'll prefer your previous headphone instead.

 

[labrat]

Del

 

[SX3900]

Why not try a vintage receiver, use that for a headphone amp. It has tone controls as well. A 45-watts receiver is going as low as $150 on ebay these days.
 
I am running my HD700 in balance mode running off the speakers output tapes.