Preamp advice

lanx0003, First, I apologize for the pedantic tone of my earlier post.  Second, you are quite correct that I neglected to take into account that a transformer can be used to reduce output Z.  I still would not call that a "buffer stage" if only because the term is most commonly used to describe a cathode follower (tube) or emitter follower (solid state). Otherwise, I think we are in agreement.  Thanks for the correction. Definitely my bad.

While we are at it, can anyone think of any preamplifier that uses a transformer output? I cannot.

I would consider the ARC Ref 3, Ref 5SE vs the LS 28 myself.  They are more fully fleshed out sounding to my ears.  As @ghdprentice says the preamp is the soul of a system to me.

OP, absolutely, drop back in model number...time as far as needed to hit your max budget. I had a used Audio Research preamp that I bought in 1979 that I had for nearly twenty years. 

Audio Research!!

@lewm Is the Raven preamplifier from Spatial Labs an example of what you are asking about?