Upgrading preamp. Best for under $1K

I am partial to tubes in the preamp by a large margin.

A used Audible Illusions or Melos would be very good if you can find one.

I have also bought 12 clone board sets from Aliexpress as well as helped modify several complete tube preamps from AliExpress for local audiophiles in the Las Vegas Audiophile society of which I am the admin.
 I can say with certainty that this one ARC clone is REALLY good as well as the EAR .https://www.aliexpress.us/item/3256801635725386.html?spm=a2g0o.cart.0.0.4b2856bacbP0UP&mp=1&gatewayAdapt=glo2usa

https://www.aliexpress.us/item/3256805647237552.html?spm=a2g0o.detail.1000014.3.6c902d7dhWEDV2&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.40050.354490.0&scm_id=1007.40050.354490.0&scm-url=1007.40050.354490.0&pvid=e59b8f66-042f-471d-9b0e-271629892df7&_t=gps-id:pcDetailBottomMoreOtherSeller,scm-url:1007.40050.354490.0,pvid:e59b8f66-042f-471d-9b0e-271629892df7,tpp_buckets:668%232846%238110%231995&pdp_npi=4%40dis%21USD%21860.00%21765.4%21%21%21860.00%21%21%402101c59116955078871795873e9863%2112000034513797567%21rec%21US%21139333621%21

I would not hesitate to buy from either seller as well. The VTA SP-13 mentioned above is locally made here in Las Vegas as well but is not as good of a value and is a but "Tubey" to me but some like to add that flavor.

The Musical paradise is the best bet if you want to tweak and play with tube and coupling caps and is a good into to basic DIY mods.

If you get into DIY then the playing field opens up a lot.