Spectron was ear bleeding on Harbeths as well... which aren't exactly ultra neutral speakers overall... not my cup of tea at all.
The only class D I've heard for full range that I could live with and listen to for more than a few minutes were Tripath implementations... and while not ultra resolving neutral, they're not exactly what I'd call warm sounding either. I tried to love the Nuforce stuff. It's ability to deal with complex music was awesome. But it just didn't have it for longer term listening. Again, midrange and top end were just not refined enough for me. ICE is good for subwoofers, nothing more, imho. I've heard a bunch of different ICE implementations and hated every single one of them for full range sound. For subs, they're awesome. For midrange and treble, no thank you. But my ears are different than a lot of folks. I like things on the warm side of neutral. I have an extreme hyper sensitivity in the 2K-8K range and, although it's dropped off a bit as I've gotten older, still have pretty good hearing way up high.... which means things that sound great to others are like nails on a chalkboard to me. Truth be told, the kind of sound that suits me for longer listening sessions is likely too relaxed for others in the local group.
I can live with slightly rounded bottom end and not quite as grippy, delineated bass. I don't like it, but I can live with it. I can't live with something that is hot or forward in the midrange. I think I'm the anti-Richard Schwery
The BAT amp here is absolutely glorious with the PSB Synchrony One. The PSB needs a bit more power for rock out volumes because of it's multiple 4th order crossovers that suck a bit of power. But 8 1940's vintage 6SN7 octals and some 6C33C-B tubes make some beautiful music on the PSBs if you use sane volume levels. I'm curious to hear it on the rosewood veneer Harbeth Monitor 40.1s that are showing up here Monday. It just might be syrupy heaven for me depending on what vintage of 6SN7s I roll in there...