I'm still deliberating between the HD800 and TH900 but I thought I'm going to ask for amplifier recommendation here since there is still a good chance of me ending up with the Sennheiser flagship. So please bear with my musings.
I haven't had much experience with high-end solid-state amplifiers designed for headphones so my experience is limited to a couple few namely the HeadAmp GS-X 2, AURALiC Taurus MK2, Schiit Mjolnir and a balanced AMB Beta22. The last one is an open-source DIY but the builder is a professional and it's a "holds no barred" build, complete with a digital volume control.
Listening impressions are done with the HD800 and TH900 using Esoteric P-05/D-05 CD transport and D/A processor stack.
The Mjolnir is not in the same class as the other three so let's leave it out of the equation for now. :-)
The Taurus MK2 and GS-X surprisingly sound quite similar to these ears with only minute differences here and there: the AURALiC unit has a meatier bass with a slight bass bloom while the HeadAmp unit has an airier, slightly more open treble. They both still have that solid-state aura about them though, perhaps what we would call a slightly cold, clinical sheen over the sound.
Which now brings us to the Beta22.
The AMB unit is really, really interesting because it doesn't have that archetypal solid-state sound: it has a liquidity to its sound that one normally attributes to excellent tube amps. At the same time, its ability to resolve details in the recordings is the best among the amps that I have tested in this comparison although I would say that the GS-X 2 is not too far behind.
My only complaints is it runs extremely hot and aesthetically it's not as nice as the rest owing to its DIY nature. Sonically though, I think it's at least a step above.
So what do I do next? Ideally I would want to avoid DIY design because I can't be bothered with the hassle but I have to admit that the Beta22 is a very tempting proposition. I would want to explore other options first though.
I'm aware that Schiit is releasing a new flagship amplifier. Do you folks think that it will have a comparable performance to the amplifiers that I've tested so far?
I'm all ears to suggestions. :-)
Last but not least, I would like to apologize for the lengthy post containing inane rambles of an old man.