It depends. Are you an analog or digital user, or both?
Do you want a built in DAC in your preamp, or do you have or plan on using an external DAC? Is purchasing new a requirement or are you open to used gear?
While I have no doubt the C49 mentioned above is a great preamp, it comes with an internal DAC which adds to its $6500 retail price.
I’m going to assume you’re talking about solid state mono blocks. If that’s the case, you might consider one of McIntosh’s tubed preamps. You can find (used) units like the C2200 and C2300 in the $3500-4000 range. That $2500 leftover would buy a lot of music or a decent external DAC. The C2300 is the last all analog pre-amp and subsequent models (through the C2600) are based on its architecture.
For what it’s worth there’s a nice looking C2200 on USAM currently. I have no affiliation with that seller.
Additionally, posters here love to hate on McIntosh despite their long term success. You’re likely to find more actual real world experience from owners on forums like audio karma and audio circle.
Best of luck with your system build.