Dante, addressing the room first is the smart move. If you still want a warmer sound after doing that, at this price point (used) you really should consider the Aesthetix Calypso - but know going in that you must replace the stock tubes to get what the unit is capable of delivering. If you want warm, with the correct tubes, that is very achievable. When you want more detail, change the tubes, there are lots of threads already with tube recs, so you really will not go in blind.
Already some great recs listed above and I am not trying to short sell any of them, just wanted to add one of the best preamps I have ever heard, that also happens to fit your budget.
Already some great recs listed above and I am not trying to short sell any of them, just wanted to add one of the best preamps I have ever heard, that also happens to fit your budget.