Upgrading preamp. Best for under $1K

Thanks for the responses! It seems tubes is the way to go for preamp but will it match well with the B&K amp?

It'll depend on the specifics, but should match up extremely well.  You can always experiment with brands and tube types to tailor the sound to your liking.

If you can wield a soldering iron and follow clear concise directions, try this:

You Can Build the PR-102 Stereo Preamplifier Kit - Akitika https://www.akitika.com/PR102.html

If not, the AVA or Schiit units are excellent.

How about this: 

https://www.audiogon.com/listings/lisb69if-audio-by-van-alstine-transcendence-10-rb-preamplifier-tube

These are well-reviewed and fit nicely within your budget - some include tuners: https://emotiva.com/collections/pre-amps

Have fun and enjoy!

I'd also recommend a Rogue RP-1 used. I had one and it took 3 upgrades to get something that sounded better. If you keep your eye out you should be able to snag one for 1k or so on the used market.