Spend some time investigating the used market to determine which preamps have stable values and which do not.
Audible Illusions and Audio Research are 2 brands that have great reputations, and hold value over time.
Vintage Marantz 7c or McIntosh C20/C22 also hold value.
If you were to audition one preamp from each of the above, you will likely hear different results from each when added to your system, hopefully allowing you to choose what sounds best to you. Then the others can be resold for what you paid (or maybe a little more....).
Audible Illusions and Audio Research are 2 brands that have great reputations, and hold value over time.
Vintage Marantz 7c or McIntosh C20/C22 also hold value.
If you were to audition one preamp from each of the above, you will likely hear different results from each when added to your system, hopefully allowing you to choose what sounds best to you. Then the others can be resold for what you paid (or maybe a little more....).