Try a Counterpoint. Good tube dynamics--probably similar to your Carver except that the bass will probably not be "giant". Most built in the 80'2 were rack-mountable, I believe. SA-3 & 3.1 should go for around $300-400 while the newer SA-5 series will fetch a higher premium. Counterpoint is out of business, although the former owner and chief designer, Mike Elliot, still services all Counterpoint gear. So, don't be too concerned about service issues. Mr. Elliot also offers comprehensive upgrades for reasonable prices. Good gear for little $!
Rack mount preamps for cheap
So I have about had it up to there with my Carver Ct-26v A great preamp but only when it decides to work. I'm looking for something under $500 used or new that sounds like the Carver (giant bass and sounds ok at lower volume levels) and it needs to actually be rack mountable, not just look like it's rackmountable (ala the carver). A 1 rack space unit would be ideal. Currently it's mated to my home studio system which has a Peavey 400CS (don't laugh, it sounds good) and some Alesis Monitor 2's I don't really need a phono section at the moment, but the upgrade path would be nice.