@hilde45 Thanks for the explanation of your gear. You seem to be searching not only for differences, but for value. Your Quicksilver and Pass amps are nice gear. I assume you’ve found the solid state preamps you’ve tried are more neutral than your tube preamp, with tighter bass, a lower noise floor and perhaps more extended highs. Those are just guesses based on my listening experience.
As others have noted, if you haven’t already tried one, the Pass XP-12 should be a good match for your Pass amp. I would expect a pre-owned unit, however, to cost considerably more than an Ayre K-5.
I hope you can audition more preamps and find one that stands out from the others.