2 or 3 hours of listening with TotalDAC A1 + Audio GD HE-9 + HD800 (unmoded).. Thus far ,  I find the result is extremely good. Best Solid state amp I heard with My HD800 thus far and it outperforms the Sonett Hands down. Precise, Ballzy with really great fast ,extended and punchy bass. Surprinsingly smooth Treble ( the totalDAC is a NOS R2R dac but a FIR filter compensate the Treble roll-off so it's not dark ). What's the most impressive is the expanded , deep realistic soundstage. Never heard that from another Solid State amp who usually offer most of the time a left/right presentation wit lack of depth. Obviously the HE-9 is on the warm side.

I thought that this amp will benefit more to the HE-6 but in fact that's the HD800 that improves the most. Stock HE-6 treble Harshness is more emphasized than with my cheap Speaker T-amp . I didn't expect that 

Maybe my impressions will change after more days of use but thus far it seems this HE-9 is an amp I could live with forever.  ..

One hypothesis is that the DAC could be unleashed by the HE-9 so I an hear more what the totaldac is capable of.... I'll try with another dac and see if the HE-9 is revealing of the source and if the sound will change signifiantly

Hey guys, I'm looking at a very attractively-priced EC 2a3 Mk 4, though it's the older version with Hammond output iron. How does it compare to the current production model, if anyone has heard both with the HD 800s.

Twice the power, but slightly behind in 4-45 in resolution, but perhaps warmer tone better suited to HD800s. Also much better selection of tubes with 2A3. The current production mk4 uses Cinemag OPTs and it is slightly better. Unfortunately, EC does not offer upgrades. Also warranty / support can be transferred for $100.

Is there anything the Asgard2 does better than the Valhalla2 for the HD800?  I'm on the verge of buying one from another Head-Fi'er, and am wondering if I will lose anything I value in audio.

For what it's worth, I value soundstage size and lower midrange the most.  Because of a slight mid-upper bass emphasis and a slight recession in the presence region around 2-3khz, the midrange of the HD800 sounds warm to me.  I'd want to make it even warmer.

I think valhalla will be better for your taste

I think you are not wrong at all. I have little exp with tubes and that is already enough (minus Leben).
No idea how Pinnacle compares to EC stuff, but this thing made me believe in all the rant that has been going on about SET-s.
The downside to that experience was my d-s dac, i hope to correct that soon.

You could anax mod your HD800 for a cheaper and reversible alternative.