What qualities stand out in really good solid state preamps?

As for "warmer", I can imagine people stuck in a room they cannot measure or tweak with treatments liking a "warmer" sound because it actually helps with some of the tonality deficits produced by their room. Without controls on these comments, there’s no way to really know whether we’re talking about the same perceptual effect. And that’s *prior* to problems we would have with interpretation of these words!
 

Appears as if you have already interpreted and perceived what is meant by these words. 

What do you look for in a preamp @hilde45 

@hilde45 please remind me which active preamp you are currently using and whether or not your new DAC has a volume control.  If it does, have you tried running it straight into your amp (make sure you significantly lower the volume!) and noted what you gained or lost compared to having the preamp in the system?  I apologize if you already did this.

@audphile1  "Appears as if you have already interpreted and perceived what is meant by these words."

The word "warmer" seems more definite than the word "neutral," and that's what I was getting at. Much of the debate here seems to be about "neutral." 

   @jc4659  My current active preamp is a loaner, one built around a burson audio buffer. I am not sure my Holoa Audio spring can be run straight into my amp, but that's an interesting suggestion!

Again, my main thrus in this thread is to gather vocabulary for SS preamp differences.

@hilde45 Thanks, I think I saw on another forum that you owned a deHavilland pre.

This whole neutrality thing seems to have discussions going around in circles. My use of the term was more restricted to having the opportunity to listen to music with and without a preamp in the path, all other parts being the same. A DAC with a volume control is one way to do this. It can show you how the preamp may be contributing to the overall sound or if it is not changing it at all.  Absolute neutrality seems impossible to ascertain since you would need to have the live recording event as a reference. After that, the sound we hear from our systems is guaranteed to be different. It gets "seasoned" by engineers, mixing/recording equipment, and playback gear including acoustic space.

When I remove my solid state preamp I like what I hear; just trying to decide what kind of seasoning, if any, I might want to add. It's a subjective thing for sure but for me it's both visceral and emotional. I know it when I hear it.  The objective attributes I look for have been mentioned by others above.  My reference will always be real people playing real instruments in a real space. 

@jc4659
I have a deHavilland type pre, yes.

The word "neutral" is anything but neutral. It’s more like a Rohrshach test that exhumes what people find important in what they listen for in their systems.

Your idea of comparing with vs. without a preamp is useful.

Neutral is not that useful a word, especially given how differently preamps can sound. For example, when I compare two preamps I’m testing, there are differences which come out that are fairly significant. [See photo below of my buddies DIY preamp built around the Burson Audio Buffer using really good caps and parts vs. a low cost L.Pass 2.0 Mos FET ] The DIY is just better in every regard. But neutrality is not at stake.

(FWIW, the L.Pass 2.0 is an amazing bargain. Dead quiet, good imaging and instrument tonal accuracy, good dynamics. $154? Who can beat that for the price?)

Live listening experiences can vary a lot. Sometimes, I find myself questioning whether I’m sitting in the best spot. I have sat 7th row center and I have sat 35th row off to the right. If I sit close to the bass section in an orchestra, I bemoan how "bass-heavy" everything sounds. It’s not balanced enough. Is that a lack of neutrality? Compared to what? -- that’s the question. Here, the answer could be (a) compared to 7th row center or (b) compared to my rig. In other cases, one venue is, itself, worse than another -- or my rig. But "better" and "worse" and "neutral" or "non-neutral" all have to be indexed to a set of criteria or they’re not helpful words -- they’re wobbly words.