Best tube preamplifier for under $15k

++1 Don Sachs pre amp. Simply amazing, and Don will tailor the output to your amp if you need.

@bdp24 I have the EAR 868 in my second system driving a Luxman M700u. It’s a great preamp too! Sweet phono stage in that unit. 

I am surprised there is so little love for the magnificent McIntosh C1100 which can be found used for less than $10,000.   Insert some Gold Lions for a little extra pop and air and you have a world class Pre Amp.

I'll add the Woo Audio WA33 Fully-balanced Headphone Amp/Preamp to the mix. It's $14,999 for the 'Elite Edition'. Made in Brooklyn, New York. I have a 1st-generation WA22, modified to preamp duty with a 2nd balanced input and love it. Perfectly silent, perfectly euphonic. Even so, I lust after the WA33. Not sure it's worth 3x as much as what I already have, but I'm sure it's a lot nicer in every conceivable way.

I am voting for the Modwright LS300...  I also use his Phono PreAmp and love it as well.  I purchased the PH9.0 a few years ago and had him add balanced outputs for me which he did with Lundahl Transformers.  The sound was incredible!  I have had the LS300 for less than a week, but I must say it was an upgrade that has wowed me.  I am using Bryston 7B mono blocks with Revel 226Be.  So yes...  a big hurrah for the LS300!