Hello everyone, just registered after lurking around here for a while! Thanks for all the insights given, so far! I'm sure there's a lot more to be learned from you all!
I've bought a Topping D70 and a pair of NC400 monos (from Audiophonics) after browsing around here. I was looking for neutral sound, a balanced pathway, and finally something that would be more or less objectively endgame in terms of quality. They seem to deliver fine in all three regards - for a lot less than some of the alternatives I looked at! My audiophile nevrosa is telling me to open up the NC400s to double check the construction quality though - but they sound fine to me so I better not to I suppose.
I'm using these to power a pair of Klipsch RP-8000F, which sound good to me. I think that Klipsch carries a (well deserved?) negative rep around here, but these speakers sound fine to me, they do not sound bright/harsh at all which is something that I am usually sensitive to. I bought them after auditioning them in a busy store and reading the review at Audioholics. Compared to some of the other speakers mentioned in that same review, these were less than half the price here.
I've ordered an UMIK-1, with it I guess I'll be able to tell how wrong I am for liking how this setup sounds. With the UMIK-1 I'll also be to fiddle around with positioning the speakers, which is going to be tricky as there is no back wall where I want to place them (the room is essentially U-shaped, and full of odd geometry with hard surfaces). Hopefully I can pick up some new insights on how to approach this from this forum, but even now I'm happy with how this system performs. If anyone has any tips for integrating adjustments from REW with PulseAudio / MPD on Linux - that'd be very welcome!
I'm also looking at integrating subs into this system, my end goal being a 2.2 system. If there is something I feel could be better as of now, it is the low end. I unfortunately missed the speaker reviews here until after I had pulled the trigger on the NC400s and speakers, and I had unjustifiably dismissed powered speakers. So, to undo some of my mistakes here, I'm looking at maybe buying some Genelec subs as they seem to take neutrality seriously, as opposed to simply being loud. A pair would cost more than my entire current system combined however.
I also recently upgraded my O2 revB to an Element 2 that I bought after double checking that it measured OK here. I mostly wanted it for that big volume knob. Now that I own the Element 2, I hardly ever adjust the volume knob after setting it to where I want it. At least it looks cool, I guess.