Need preamp recommendation

What power amp do you have?

What features do you need from a preamp? I've been looking at preamps extensively as well in that price range. I have been curious to see what tubes would do in the chain to go along with a SS power amp.

These three are on my short list - and can all be found under 4k used. The Rogue is a hybrid design and the other tube are all Tube. The Rogue and Backert Labs are made in the US if that matters.
- Backert Labs Rumba 
- Rogue Audio RP-7 
- Primaluna EVO 400

I agree that the LTA preamps are enticing. I personally would want the one below. I've read that it can sound a bit lean so matching with amplifier is key.

https://www.lineartubeaudio.com/products/microzotl-preamplifier