can a SS preamp do the tube amp justice to maintain the tube amp's liquidity, sweetness, wonderful midrange, etc.
Yes, certainly, if the two components match up well.
The 6Moons review of your amplifier describes its sound as follows:
Extrapolating from that, we can characterize the RM 10 as slightly on the lean, fast, accurate and linear side of the common tube fence. Comparing that assessment against what I sense are Roger Modjeski's sensibilities as a designer, it seems fitting, factual and deliberate.
Given that, what would probably be the best matchup would be a solid state preamp that leans (or errs) in the direction of emulating a tube-like sound, rather than one that tends to be toward the analytical/resolving part of the spectrum, or even at the neutral center.
I can't comment on the Capri, but I would suggest that several of the 1990's Classe preamps fall into that category (solid state preamps with tube-like sonic characteristics), including the DR5, DR6, CP50, CP60, and possibly the CP35. I currently use a CP60 with a Chinese-made Paxthon 8 x EL34 (not 84) 80 wpc amplifier, and I've been very pleased with the combination. Most notable, I would say, is that the soundstage produced by this combination is enormous, although I attribute that more to the power amp than the preamp.
I've also had very good results previously with a vintage Mark Levinson ML1 solid state preamp driving various hi-end vintage tube amps, including Marantz 2's and 9's (which I no longer have, in case anyone reading this is tempted to ask).
Regards,
-- Al