$20k(ish) tube preamps

I heard the CL-1000 at my dealers store. It is neutral and very detailed. I heard the preamp hooked up to the Luxman 300B tube amp. Excellent combo. It's similar to my CL38U SE but is a few steps quality wise above mine. There is someone on Audiomart selling a CL-1000 for $6000 off the regular price.

Audition a Zesto Leto Ultra II   , they make great tube preamps 

Absolare Preamplifier.

Atma-Sphere MP-1.

At your budget, you can add the Caddock resistors, and just about all the 'upgrades'.

Though Ralph Karsten is the manufacturer, I would either call or PM him (atmasphere), to get his take on this. He knows just about all that is available, and can give you accurate information, sans bias.

Bob

Call Tom Vu at Triangle Art Audio.  The L200 is really good.