Bryston BP-17 cubed or Benchmrk LA4 Preamp

Given what you’re looking for sonically you’ve identified two excellent candidates IMHO.  I can’t speak to the Benchmark, but I owned a Bryston BP6 (very similar to the BP26 minus the balanced connections and separate power supply) for years and it is the quintessential “straight wire with gain” type component.  It simply passes on what it’s fed without editorializing, and it’s very quiet that leads to a large 3D soundstage due to what I perceived was a complete lack of background noise so individual images just pop to life.  I’d guess the BP17 sounds more alike than different from the BP6, but that’s just an uninformed guess that it maintains much of the Bryston house sound.  Just my experience FWIW, and best of luck.

I've bought preamps twice.  Both times I did a bunch of research, obsessed over it for a while, and then decided I didn't believe 98% of what I read and just bought Brystons because I believed they were close to as good as you can get and last forever.  I bought a BP25 for $1000 in about 2008 and a BP26 about 5 years ago for about $2100.  Both work perfectly.  No noise in the knobs, connections all work perfectly.  When I replaced the BP25 with the BP26 I thought it eliminated a very slight honkiness but it was so subtle that I only noticed it that one time.

Very sensible. This was my approach when buying the Bryston 2.5b cubed.

The LA4 seems pretty good. Tough choice!

I’ve owned both as well as the 2.5B, and while I often extol the virtues of the Benchmark, I would recommend the Bryston in this case.  The Benchmark is quieter and very transparent, but the Bryston is more musical especially with the 2.5B amplifier.  The  amp has a bottom up voicing and the preamp a top down voicing IME, and therefore they are very synergistic.  The preamp is very fast also, very immediate.  But ultimately you probably couldn’t go wrong with either.  The Benchmark holds their value well.  The BP17 can be had used for just over $2k.  My only problem with the Bryston was it was slightly noisy in my system (I.e., a hiss coming from the speakers, whereas the Benchmark is dead quiet).  

@jimmy2615 

Extremely helpful insight. I don't think that I am sensitive enough to pick out this subtle effect, but I'm glad you can.

I don't really know if my system is on the warm side or cooler. I have nothing to compare it to. No local audio nuts or stores nearby. I purchased a Cary 120s tube amp to get a warmer sound, but found that it did not appreciably alter the sonic presentation. My preamp is the ML No. 38s and speakers are Usher V-604. The Ushers provided a touch of warm. I want more. No more tubes for me.

I've had a the Levinson No. 38s in my system for so long, I can't remember how it affects the sound.

I'm not sure if you are familiar with the No. 38s sound. It is a pretty old unit. I've read a Stereophile review that it describes it as "neutral" which can mean "clinical" or "etched" or "detailed". Perhaps this preamp is pushing my system toward the cooler side.

So my questions are: will the BP-17 cubed be warmer or colder than the No. 38s in my system? What are my options for a warmer sounding preamp within the $6K price limit ($6K new list price). Any Bryston preamps?