Reasonably priced preamplifier

Check Wyred4Sound STP-SE.

Try a Schiit Freya +, very highly regarded with more flexibility than the pricey stuff and has absolutely superb sound. Rated "class A" for a reason...it deserves it.

A couple years ago I ran through a series of highly regarded amplifiers. I'm a tube guy so keep that in mind, but I landed on ModWright, in particular their ls100. It's not fully balanced but Dan will put a transformer in it if you want. For me, this preamp is clear without being overly analytical, it's quiet, and it's musical as all hell. The only thing I dont like about it is the remote seems kinda cheap. The music room sells them and they have a pretty generous return policy. There are other models you might like better as well but I've been very impressed by Dan and his products

@gopaljeen  Townshend Audio Allegri Reference Passive preamp. There are a few lightly used ones for sale on us audio mart in your price range.

It has received many excellent reviews.

The PS Audio BHK is a very good choice for the price.  But if willing to pay the 7-8k pick an Audio Research ls28se.  In my opinion almost as good as a Ref6.