There are several preamps in that price range that I either currently own or am very familiar with. For something on the warmer side, the Audio Mirror T-61 is excellent. An older Classe (DR-5) for instance, sits on the other end of the fence; not quite "clinical", but more neutral with a little more detail. A notch toward warmth from the Classe is a Musical Fidelity A3cr, and another notch toward the Audio Mirror is a Marsh p2000t.
All are excellent preamps, and can be had used for about your desired price.
Michael
All are excellent preamps, and can be had used for about your desired price.
Michael