You have gotten a lot of good input. I was in a similar situation to you recently, looking for a tube preamp to mate with my Pass XA60.8. After much research, I decided a 6SN7 based preamp was what I was looking for. That led me to the Aric Audio Motherlode. Aric worked with me to make it truly balanced with some other enhanced performance qualities. As a result, the Motherlode XL is now an offered product just slightly above your price range.
Over the years, I have owned ARC Ref 5, Pass Labs XP22, Doshi Alaap, McIntosh 2500, and Lamm. While they were all good in their own way, I found each to be lacking in some area important to me. The Motherlode XL has all the qualities I was looking for and has overcome what these other preamps were lacking (in my opinion). It is very dynamic and punchy, very detailed throughout the audio band, big deep soundstage with clearly separated images, beautiful tone, and dead quiet. It took my system one step closer to sounding like real live performers. While I'm still exploring 6SN7 tubes, it is easy to hear differences. For example, using Hytron 6SN7, it is warmer with softer transients. With Sylvania Bad Boys it is more neutral and dynamic.
Most importantly, it mates beautifully with my Pass amps. No hum, buzz, or tube noise at any volume level. It is handmade in the US and working with Aric was a true pleasure. He will build it to your specifications and recommend various tube combinations to suit your taste.
I didn't know much about Aric Audio before this, but he deserves all of the accolades he is getting on Audiogon and in professional reviews.
Good luck and have fun in the process!
Dave