Alright, just got 5 MUSES02 and a pair of MUSES01 in the mail--those ebay fakes you know lol.
First off, not that I really care much or I like to argue, but I have very little reason to assume these are fakes. Lettering, holes and pins are exactly the way the "true" MUSES have been described; and beyond that, the sound kind of confirms their genuineness as far as I'm concerned. And yes, the pins are actually pretty flimsy compared to my usual chips, so much so you could bend them beyond repair way too easily... Be warned...
Anyway, onto impressions now. I tested (I'd love to be allowed to say "put to burn-in" but I'm afraid I'll get a public stoning if I do lol) three MUSES02 in my iBasso D10 (one I/V, two buffers) first. Pretty immediate difference compared to my three OPA627AU combination from before. Replacing the I/V opamp made a huge difference (both in terms of sound quality and "flavor") whereas swapping the buffer opamps made more of a "sound color" difference listening upon first listen, even though the sound quality clearly ramped up at the same time.
These are obviously pretty powerful chips here, heavy hitting and loud. Not exactly neutral right out of the box, bass seems a little overwhelming (D10 is connected to my old iRiver H120, while this is a great mobile setup, with pretty good sound quality, the bass does have that "jitter party" effect where it is more thumpy than tactile, and the MUSES02 kind of emphasizes that), but soundstage and sound quality are on a total different level from the previous chips, cavernous (not large) and wet (not grainy). If the bass gets a little tamer after a few hours--wait that's impossible, I forgot, semiconductors don't evolve with time!-- this could be a pretty good opamp for a mobile setup, where "loudness" and bass with a good level of detail can be more important than the hyper-critical detail retrieval and resolution I would look for on my home rig.
MUSES01 now. Tested a pair of these in my DAC output, in my main home setup, replacing two pairs of AD797BR opamps--my reference chips up to now--feeding my tube headamp. Interestingly, the first second of the first song I played, I noticed the difference in sound quality with the AD797, but I also noticed no change in sound "color" or "flavor". What does this mean? Well, simply that the MUSES01 is a better opamp than the AD797 in that position, but that's it's just as neutral, which is both good and what I'm looking for (last thing I need is a "colorful" opamp in my DAC like the OPA627...).
The sound is nicely balanced throughout the whole frequency spectrum--if anything, I find myself expecting a tad more bass out of the box, but I'm pretty sure that will solve itself in the first few hours, you know, brain burn in-- with no frequencies dominating the sound. I am hearing more details than with the AD797, better defined, both spatially and in resolution; the soundstage isn't particularly large as I've read (it is a little larger and higher than the AD797, but not deeper), but very 3D-holographic sounding with pleasantly realistic instrument placement and separation. No particular wetness here, apart from what the tubes add in my setup; just a neutral 3D ultra-detailed sound: a better-made AD797 really... I'm surprised by how similar these chips sound--or don't sound actually, since they're so neutral...
Anyway, I will "monitor" the evolution of the opamps in both setups, and report back when my brain has burnt-in lol.