tube pre amp for cary six pac tube amps

looking for late evening warmth. female vocals, mellow strings from the likes of mark knopfler, cowboy junkies, bonnie rait, eva cassady and the like. cary slp is a natural fit but any other quality tube pre recommendations would be appreciated, budget: +/- $1,500 (used, older but well regarded is therefore my domain). thanks for your thoughts and suggestions, including tube recommendations.