WraithApe
Headphoneus Supremus
Perhaps, the lifeless, sterile sound of SS amps is commonly blamed on the huge amount of negative feedback that they require and negative feedback inherently reduces all types of distortion.
The problem is, the HD800s are inherently lifeless themselves because their strength is their weakness, that being the fact that they are super neutral and have no real personality of their own, they are like a blank slate, they sound like what you feed them. So if you feed them an amp that has huge amounts of NFB then they will probably sound sterile as a bone.
I'm sorry, but that just isn't the way I perceive the 800 - inherently lifeless - and in so much as you "hear" an amp, I don't think of SS amps in those terms either. Neutral or flat isn't necessarily the same thing as sterile or lifeless. Maybe it's just me, but I don't really want my headphones to have 'personality' - the personality is in the music, and I just want the most accurate reproduction of that music possible.
A tube amp like the one I have now can literally sound like the singer is physically in front of you depending on the quality of recording. So even though solid state amps have technically less distortion, the perceivable realism just isn't there compared to a good tube amp.
This notion of realism seems quite a subjective to me. What makes something real for one person, may not be the case for everyone. Personally, I've never felt the imaging of headphones placed a singer or instrument outside of my head-space. I only really get that kind of feeling from a full speaker setup. You say I have to see for myself re: tube amps, but I've been there, done that. I owned a Woo Audio and an Icon Audio tube amp for some time previously when I started getting into higher-end gear and used to pay too much heed to the audiophile press. I doubt I will go back to tube amps myself as I'm not convinced of their benefits but more than that, the endless tube rolling is a real PITA!