What qualities stand out in really good solid state preamps?

Krell and mark levinson .

@rolox 

I find it very amusing to read that apparently, for some, there isn't audible differences between solid state preamps?!? 

Come on.

Every circuit has a "sound", even when it seems very transparent / neutral, if you compare it with another circuit, you will spot differences. It can be "more drive", "more depth", stronger bass, whatever. Solid state preamps DO sound different, just like the rest.

Exactly exactly exactly.

There are many posts which just rely on lazy words like "invisible" or "transparent." That is evidence to me either of lack of perception acuity or lack of linguistic facility. Ok, maybe SS preamp A is very hard to distinguish from SS preamp B. Fine. But to say this *class* of gear lacks differences is repugnant to reason.

Music is thinking rythms dreaming a melody.

Any system well embedded and well chosen , with or without preamplification, will give you that.

The only rules are synergetical choices coupled with acoustics...

Each one of us differ by his needs and by his specific constraining conditions.

Marketers want to convince you that a specific  piece of gear is the solution by itself...It is not even wrong but beside the point ...

Many thought that sound exist or the aspects of sound exist as "neutrality" by itself in an absolute way which is all measurable in some objective way for some or separately all evaluated in some subjective way only . But sound perception is an inseparable objective, subjective and intersubjective and historical conditioned dynamic process.Not a mere state.not an isolated factor.

Then the material conditions as difference between two preamplifier be it two tubes one or two S.S. one will be also part of all the material factors at play...

Sound is like perfume blend , it result from an objective recipe determined by acoustic or chemical  and physical materials parameters and subjective impressions and intersubjective impressions but also statistical studies in acoustics or in perfume industry ...

Sound is as sensual and visceral as odor perception in his intimate revelations(human voice timbre meanings) and as abstract and as concrete as visual conditions in their general and universal display (spatial properties of sound and spatial geometry of sound as in echolocalization ).

«The ears are like two noses who had learned together not only to smell the inside but how to see the outside »-- Groucho Marx studies in kitchen acoustic 🤓

«The nose knows in a primal way what the eyes only believes but which the ears can understand»-- Groucho Marx neurology studies 🤓

«The ears think» -- Groucho Marx studies in the womb 🤓

« Then why did the ears do need so much a mouth? »-- Harpo Marx 🎼

«Because silence is already a music in need of a sound»-- Groucho Marx

«Right the dancing body is not enough I need my harp to think and speak »--Harpo Marx 🎼

I find it very amusing to read that apparently, for some, there isn't audible differences between solid state preamps?!? 

Come on.

Every circuit has a "sound", even when it seems very transparent / neutral, if you compare it with another circuit, you will spot differences. It can be "more drive", "more depth", stronger bass, whatever. Solid state preamps DO sound different, just like the rest.

@audition__audio 

I think it more advisable to feed your S.S. amp with a tubed preamp and in my experience this seems more common.

It's more advisable if the question is "What's better? Tubed or SS preamp?" But, if you read the OP, you'll see that is not the question. It's not an "either/or" question. It's about the differences between SS preamps. 

Had Pass XP-12 into Rogue ST100 tube amp. No problems and sounded good. 
Matching tube preamps (typically higher output impedance than SS counterparts) to solid state amps (typically lower input impedance than the tube amps) is where you need to be careful. Everything else is a matter of sonic preference. 

I think it more advisable to feed your S.S. amp with a tubed preamp and in my experience this seems more common. Very few if any disadvantages to tubed small signal devices versus tube amps which need to be matched more closely with speakers. Especially true of my OTLs. 

They are typically very quiet. Neutrality but not at the expense of texture and proper color. Most S.S. preamps I have heard dont get as many things right as the more neutral/linear leaning tubed models. Perhaps oversimplification would be a good word to apply to many S.S. preamps.

Great post!

Especially true if we refer to gear pieces to define and learn about any concept instead of acoustics as a reference, the way we create ourself "neutrality" in a system room teach much more than using a new piece of gear...

Then for reason relating to the characteristics of our system parts /room and specific synergy what we look for will differ for each of us. For example i was looking for a more "organic" synergy , then i pick up tubes preamplification to couple it with my dryer active speakers.... Luckily it was a match in heaven....But the same preamplifier may appear as "trash" for another person needs, and system/room characteristics and level ....There is no rule  in brand name choices preamplification  for a synergy... Electrical specs compatibility but it is not enought to create synergy which ultimately is an acoustic experience...

Growing up where only English is taught/spoken and moving to/working where several languages are taught/spoken (and where English is a second language), it became clear the inevitable pitfall of trying to tie down meanings among people for audio kit adjectives that have been adapted from other senses (at the most proximal) or completely unrelated contexts. This seems a very fast-moving target be it for preamps or something else.

But admittedly, the notion of potentially feeding a SS preamp to a tube power amp had me curious just for how unconventional it is!

“Hey Siri / Alexa, where can I find a dozen + takes on audio neutrality?”

😉

Growing up where only English is taught/spoken and moving to/working where several languages are taught/spoken (and where English is a second language), it became clear the inevitable pitfall of trying to tie down meanings among people for audio kit adjectives that have been adapted from other senses (at the most proximal) or completely unrelated contexts. This seems a very fast-moving target be it for preamps or something else.

But admittedly, the notion of potentially feeding a SS preamp to a tube power amp had me curious just for how unconventional it is!

@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.

@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. 

@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 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.

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 

@ghdprentice

Good point about calibrating to live music. I suppose that would establish a correlation that could transcend categories. Well put.

Of course, a lot of amplified/studio music should NOT be gotten "correct" because they are compressing and shaping the sound so it pleases and grabs attention when played of mass market headphones, cars, etc. One does NOT want to hear the original. Like a bad casserole, if it’s not corrected somehow, it’s barely edible.
Here’s a pretty tendentious but convincing view on this: https://youtu.be/j_sa915TD-o?si=tOXaeeZvglEhpdAi

The point is that "being in the studio" is kind of meaningless, because they are making stuff to be played by others. The chef cooks food that most customers will like, not what she thinks is "true" or "best."

@sameyers1
Knowing how the XP-12 performs, especially with my XA-25 would be revealing.
I have heard neutrality with a very good passive autoformer. I didn’t like it. Lifelessness -- in that system. Now that I have a DAC with more voltage output, I might try that again. A friend with the Bent/Tap X is done with preamps. he loves it. After 30 years, that’s all he wants in a preamp.

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!

Neutrality is also problematized by our varying physiology.

To comment a bit more -- not about anyone’s comment in particular -- I ask myself, What’s the pragmatic upshot of neutrality? It cannot mean some objective "getting back to the original recording," not least because we'd never be able to confirm we had done so, and most importantly because the original recording is just prime matter which is yet to take on the forms imposed by its varying instantiations (in people's varying gear, ears, rooms, tastes, etc.

Still, we can practically know when something has been added. If I eat a burger covered with black pepper, I would know that’s not neutral. This was ghdprentice's point, I think. One has various baselines and they can notice when there's "something added" vs. "baseline." Objectivity is a pragmatic concept, not a metaphysical one.

@gfguillot
"the more you spend the more you’ll hear in the sound."
Having connected with audiophiles with an eye for small makers and DIY, I’d say the more you KNOW the more you’ll hear in the sound. (And sometimes you know you need to spend more!)

I recommended the XP-12 to @hilde45 in his other discussion. It’s an easy recommendation and synergy with XA25 isn’t even a conversation. But it all depends on the objective and what you’re trying to do. 

@audphile1 Kudos on your upgrades. I wish they were within my budget.

Do you think the Pass XP-12 is a good fit for the OP, @hilde45 and his Pass Xa-25?

@sameyers1 and @decooney 

I had XP-12 for a while before moving up to XP-22. The 12 is a great preamp and gives you a good dose of that natural, warm and extended Pass sound. I had it paired with XA30.8 driving Wilson Sabrina. Upgrading to XP-22 was a good step up though. By no means it’s a night and day difference because the XP-12 is already very good. But there are few major differences mostly due to the separate isolated and beefed up power supply. You get lower noise floor that allows more subtle details to come thru and become more apparent rather than being buried into the mix, better overall clarity, more authority and texture in the bass and bigger, more solid imaging with better instrument separation.
It retains the Pass Labs natural, extended and warm sound signature and the better details it conveys are never in your face. My next upgrade was going from XA30.8 to X260.8. The XP-22 scaled up no issues. 
I’m not a fan of a two box solution but I’m willing to deal with it given the sonic ROI you get. 
 

Here’s XP12 :

and the XP-22 for comparison:

I am a big fan of Schitt gear. My second headphone stack is Schitt based as is my main DAC for 2-channel. However, the Schitt SYS is not one of their better efforts. It is not a clean window into the music. Less is less in this case. I have my SYS gathering dust in a box somewhere.

@sameyers1 decooney I have only auditioned the XP-12 in my home and can’t speak to the characteristics of the higher end or older Pass models.

i agree with your observation that people sometimes upgrade only to wish they hadn’t sold or given away a piece of gear. Some folks on this forum post of having repurchased a piece they’d had before.

So true, being near Pass Labs 30m away, lots of it around here - I’ve also helped a few even try and buy a few different cables and sources and dacs instead of getting on the upgrade merry-go-round, to then see those same people jump again to nice tube preamps. I needed confirmation from the man myself that my own 6SN7 preamp would be a decent match for an upcoming Pass/Forte’ mod project I was planning. I chatted some with Nelson about this 4-5 years back, and the following year he came out with the NuTube Korg kit for those who wanted to try something else. It might be fun to find out if the XP12 could be modded some, trying that, or this, as another approach fwtw. Just batting around some other ideas.

Intially looking for preamp I was thinking features on board dac etc, but then I figured you can't beat a separate preamp and dac from a purist stand point.  I liked the Mcintosh C53 and the Classe' Delta preamp when it came to features.  Then I decided I need simple but high performance and quality, basically inputs and the best volume control of the signal is what I want.  I narrowed it down to a used Pass Labs X-12, Ayre KX-5emp and an Ayre KX-5 Twenty, with the latter being much more even if I could find a used one.  I found one and stretched to purchase the Ayre KX-5 Twenty.  It's solid, the resolution at lower volumes is phenomenal and it's very dynamic and yet flat across the spectrum.  Very detailed and airy, I definetly can tell it's a quality component.  

I didn't do any demo, rolled the dice when I bought it thinking mainly cost is relavent to performance.  With some preamps it's the features, I was just looking for the best I could afford that controls the volume between the source and the amp.  The Ayre KX-5 Twenty delivers that performance I was looking for but there's plenty others that compete.  As we all know, it's how deep you pockets can go in this hobby, the more you spend the more you'll hear in the sound.  I wish I could afford a Ayre KX-R Twenty preamp, but that's the price of putting a decent vehicle in the driveway..

What qualities stand out in really good solid state preamps?

in my book for solid state pre’s is that they first and foremost do not damage the music signal going through them

then it would be the ability to adjust and maintain volume level by each input (to allow useful a/b comparisons)

Neutrality is an acoustics concept BEFORE being used in gear design...

The sound experience is an acoustics experience first and last....

There is too much variations in price levels and needs and synergetical variations to define a rule valuable for all systems,speaking about preamplifications...

People as usual gave their take on the branded named preamplification of choice... Why not ?

But it will be acoustics knowledge ( not only room acoustic) that will matter as much as gear synergy if you have a budget...

@sameyers1 response to socks

Everything on the forum is opinion and based on individual experiences. You can say I’m arrogant. I can say you’d do better to not to get angry and recognize everyone’s right to post their thoughts and find a respectful way to disagree. I hope you can accept my response in the spirit in which it is offered, as a further explanation of how I characterize neutral.

You are much, much too nice.

@decooney I have only auditioned the XP-12 in my home and can’t speak to the characteristics of the higher end or older Pass models. 
 

i agree with your observation that people sometimes upgrade only to wish they hadn’t sold or given away a piece of gear. Some folks on this forum post of having repurchased a piece they’d had before. 
 

Many of us get upgraditis. I’ve auditioned gear in my home that I thought sounded better only to find I couldn’t justify the additional cost for the incremental improvement. In one instance a dealer loaned me an excellent Luxman amp. I brought it hone and it sounded great until I put on a large symphonic piece and it couldn’t handle the power requirements of the transients and started audibly clipping! The dealer concluded it was likely because of the 86 dB efficiency of my 4 ohm speakers that drop to 3 ohms at some frequencies. It’s just another reason to audition gear in your home with your other equipment. 
 

@soix 

"...everyone needs to define that inherently indefinable neutrality for themselves. I think this is a big part of the art — and wonderful, awful struggle— of ultimately putting together a great-sounding system." 

Great point.  The "struggle" part comes in when people chase some sort of holy grail of sound by constantly "upgrading" to equipment that others report to deliver "neutral" sound, when instead, they should simply trust their own ears and stick with the gear that sounds the most "natural" (i.e., good) to them.

Acoustic Research ’sound’!

Any vintage: suppose seller says ’everything works! all new tubes!

My friend just bought a new to him Vintage Acoustic Research Tube Preamp, to replace his slightly older Acoustic Research Tube Preamp. He put new tubes in the existing unit, everything works, Acoustic Research ’sound’ right?

I went over, we did a few hours of comparative listening. The new to him unit was clearly superior, the existing unit’s sound much less focused, even wandered while listening to great Mono LPs, newer unit simply wonderful.

Some innards of the older unit ’work’, but not like they should, and if that was your first Acoustic Research listen, you would probably walk away, thinking Acoustic Research ’sound’ was not for you, and perhaps post negative comments here based on that single experience.

I do not believe in ’generalizations’.

btw, I ended up with so much more respect for his speakers after listening thru the newer Vintage AR preamp. What a difference.

I have nothing but good things about his AR Preamp/Amp combo's sound.

@soix I never said I knew better than anyone else, you did. I never said my statements were objective fact, you did. I made a point of saying everyone has their preferences and prefer different gear. And objective fact is what exactly? Some people on this forum downplay the value of testing equipment using measurement gear. I can understand that, as measurements don’t tell the whole story in my experience. My ears are my reference measuring device. So what is objective fact? In listening to music it’s mostly subjective I think. 
 

You’re right that I don’t know exactly what the original recording sounds like. I wasn’t in the studio or at the venue. But I do know what a piano should sound like. i’ve played one for decades. It’s why I listen to solo piano recordings and solo acoustic guitar recordings, as I know what those instruments sound like quite well, Yes my piano in my room sounds somewhat different from another piano in a different room. But it is the best frame of reference I can have to know if a piece of gear sounds true. The OP uses a violin to evaluate gear for the same reason. Perhaps I should have said that a simplistic view of neutral is that the gear is true  the sound of the instruments. 
 

When I audition gear I use recordings I know well that I find to be true to the sounds of the instruments I know. I can hear a loose/flabby bass, a bloated midrange, a lack of treble extension. It’s similar to what people do every day when they tune their guitar or flute or clarinet. And I compare the gear in my home to what I own. It’s not perfect, but again it’s the best anyone can do I think.

Everything on the forum is opinion and based on individual experiences. You can say I’m arrogant. I can say you’d do better to not to get angry and recognize everyone’s right to post their thoughts and find a respectful way to disagree. I hope you can accept my response in the spirit in which it is offered, as a further explanation of how I characterize neutral. 

Audionet makes the best preamps in solid state I heard full stop!

Mola Mola good too.

@soix Ditto!  👍👍

A number of people who posted comments have dissed the concept of neutral. A simple view of neutral is that a device (preamp, amp, dac, speaker, cables, whatever) does nothing to change the recording. It’s not complicated.

@sameyers1 Oh but it absolutely IS complicated. You don’t know what the original recording sounds like any more than I do. For you to say YOU know what’s neutral is your — and ONLY your — opinion and not based on objective fact at all unless you have the recording engineer sitting in the room with you. Who the hell are you to say to anyone else what’s neutral? It’s just your interpretation based on your ears and taste and nothing more and is not translatable to anyone else. To say that you know what neutral is better than anyone else is just arrogant and silly IMHO.

@sameyers1 "A number of people who posted comments have dissed the concept of neutral. A simple view of neutral is that a device (preamp, amp, dac, speaker, cables, whatever) does nothing to change the recording. It’s not complicated"...

Following your lead, here is a simple view and question, and not too complicated. The XP12, XP22, XP33, each sounds different. And for some audiophiles, the next version is better than the last, and so they upgrade and sell the prior version.

-or- If anyone else cares to respond, feel free to chime in -

Are the earlier versions less neutral than current versions, and what makes the latest versions of Pass Labs preamplifiers more neutral, or better, or different enough to want to make the next-level-up upgrade?

@hilde45 I hope you're able to audition the XP-12. You and I seem to have somewhat similar listening preferences. You mentioned violins as a benchmark and how your tube preamp leaves you wanting more detail and leaves you thinking you're missing some of the top end. I find the same is true when listening to an acoustic guitar with some, not all, tube preamps. And acoustic music, with no amplification and in a great venue, is a great yardstick to use in testing gear. I use a solo acoustic guitar recording, a solo piano recording, both jazz and classical, as well as big bands and symphonic works when I try out gear.

A number of people who posted comments have dissed the concept of neutral. A simple view of neutral is that a device (preamp, amp, dac, speaker, cables, whatever) does nothing to change the recording. It's not complicated. It's why people with high quality gear note that if a recording is poor in quality, or vinyl is poorly pressed, they hear all the defects in the recording. It all gets passed through by their gear. The gear provides a very high level of detail and accuracy to the recording. The frequency response is flat, with no emphasis on any frequency. Audible distortion and noise are virtually non-existent. The device plays back a signal that is true to the recording. To me it's much easier to accomplish this with electronics than it is with speakers or your listening room.

What matters is what sounds best to you, me or any individual. Our listening rooms introduce anomalies, distortion, reflections, etc. Our hearing does the same. So we can start with great gear and still end up with issues. But the concept of neutral is not complicated. And not everyone likes what I've called neutral. There is a large following on this forum of folks who love the "warmer" sound of some tube gear. I respect that and understand why, as I own a tube phono stage and a tube amp, the latter in a secondary system. But that "warmer" sound is typically not neutral, with an emphasis on the midrange.

Everyone should just respect that we each have preferences as to what sounds best. And as others have noted, it is important to consider the compatibility of one piece with another. It's one reason why I think the Pass Labs XP-12 would be a great match for your Pass Labs amp. Pass designs its gear to work together, with preamp output characteristics compatible with their amps' input.

Hope you find the solution you're seeking.

OP…”That sets a benchmark for those sorts of concerts; but does it do for mixed, PA-driven live music, EDM, etc. what it does for acoustic music concerts?”

Actually, if you think about it, by having a true reference for your system vs the real acoustic world… then you have calibrated your system for all music…and it is going to be correctly interpreting music of any genre.  Then if it was mastered incorrectly… well, it was mastered with a bias. 
 

To get amplified / studio music correct, you would have to reproduce the same electronics / speaker system they were mastered on… and it would only be good for that studio. 
 

but frequent doses of live unamplified music in varied reverberant spaces in a variety of genres will do wonders in your search for…… ? 

exactly why we  ( some of us ) and in industry make own reference recordings and or sponsor same…..

coloration starts with microphone selection and placement…..

yes…there are a few companies chasing accurate…..

@decooney @soix 👍
 

"Neutral" as compared to what?

Who set the industry standard baseline reference as to what neutral really is. 

This is the funnest and funniest part of the whole (hole) discussion. 🤣 

I think the problem is with using the term “neutral” as if it’s a fixed and definitive thing when in reality it’s a moving target based on each individual listener. Unless you’ve made a recording yourself, let’s face it, there’s no way for any of us to define what neutral truly is. In that way it’s kind of a waste of time and a fool’s errand to even talk about neutrality because it’s like trying to catch a greased chicken. What I think sounds neutral might sound colored to you and vice versa, and neither of us would be wrong in the context of our own hearing and tastes. And the basic fact is that neither of us knows what the actual performance sounded like or what the final mixed version should sound like because we’re not the recording engineer. Personally, I’d rather focus on what sounds “natural” — natural meaning nothing sticks out and everything comes together and sounds balanced and effortless like real music and, most importantly, just sounds “right.” THAT, to me, is the best “neutral” we can achieve, and everyone needs to define that inherently indefinable neutrality for themselves. I think this is a big part of the art — and wonderful, awful struggle— of ultimately putting together a great-sounding system. But that’s just me.

@sameyers1 

"Pass Labs XP-12…is just slightly on the warmer side of neutral, the Pass Labs house sound, and it images better than my Ayre." 

Ok, now we have a targeting lock! Thank you -- this is up to the top of my list. Thank you!

@skinzy 

"the reason some folks report improvement with a separate preamp is their DAC preamp or power amp are not compatible"

That invalidates their comments, unfortunately! 

@ghdprentice 

"There is a way to determine neutral. And it is by becoming intimately familiar with acoustic music in multiple venues."

That sets a benchmark for those sorts of concerts; but does it do for mixed, PA-driven live music, EDM, etc. what it does for acoustic music concerts?

That said, I've been to many acoustic concerts where the location I was sitting or the hall itself made the mix of sound pretty bad. I have sat there thinking, "I wish this was playing on my rig."

@ghdprentice correct! If you look at my post listing the qualities I look for in a preamp, you will see that we’re on the same page. Your last paragraph pretty much echos what I stated and sums it up. 

@decooney “For a component that is "supposed to be neutral", "adding nothing", looking at history of threads and posts over the past 15-20 years…”

You bring up some good empirical evidence that neutral is not what most people are looking for… although they say they are. 
 

@audiophile1 “I’m trying to refrain from using a term “neutral”. I don’t know if my streamer, DAC, interconnects, cables and components downstream from the source are neutral. There’s just no way for me to possibly know that unless I can A/B what I am hearing at home with what it sounds like in the studio mixed…” 

Good point, but.

There is a way to determine neutral. And it is by becoming intimately familiar with acoustic music in multiple venues. I started my quest a couple decades ago when frustrated that improving one genera would make others sound worse. Over ten years with season tickets to the symphony  (7th row  center) and dozens of acoustical jazz and individual instrument concerts I was quite startled to realize what real music and venues sound like. While there are some characteristics of rock concerts that translates to a system most do not. 
 

When I listen to most systems now they do not sound neutral at all. They are often overly detailed… high lighted details that while interesting makes the venue, miking, mixing, or certain instruments stand out. When cymbals sound like solo instruments, or a triangle grabs your attention then that is not neutral.
 

Bass in natural environments is very nuanced… not slam. My earlier concerns about slam is that the fast slap of bass is not real… in the real world symphonies or rock concerts it is a slower wave with nuanced details. Solid state amps tend to be really good at exceptionally fast rise times and over slap. Now I have realized that even really powerful ones tend to run out of power and therefore do not follow through with the detail.. the articulation of the different frequencies and nuances as the bass arrives. This is something tube amps do well, they reproduce the overall bass experience and nuance well, not pardon the phrase “shooting their load of electrons” on the first wave. Or, at least this is my current theory.

Ok, I could go on and on. But I think neutral is actually the objective of few companies and customers. It is what sounds better to them, which is often hearing things they have not heard before or accentuated instruments or frequencies.   But there are companies and folks that are out to reproduce music as it occurs in the real world.

@hilde45 

"Surprised Bryston never crossed your path.''

I always respected Bryston but just never had a good reason to own any of their stuff.  I looked hard at the 28B3 amps for a short time but moved in a different direction.   The thing I always wanted to hear was their speakers, which I suspect may be underrated, but that is just a guess.  Well made gear and a solid company by all accounts.

Beyond a volume control and component switching a preamp can help with matching the impedance between the source components and the power amplifier for optimal signal transfer. I think the reason some folks report improvement with a separate preamp is their DAC preamp or power amp are not compatible. Likely the power amp has too low input impedance relative to the DAC  preamp.

@hilde45 Ok, since I’m on a roll and correctly assessed the reasons you’re interested in finding a suitable solid state preamp, I will reiterate my recommendation of the Pass Labs XP-12. While it’s their entry level model I found it better than my entry level Ayre K-5emp. It’s a newer design and about double the cost today of what my Ayre cost years ago. But most importantly it is just slightly on the warmer side of neutral, the Pass Labs house sound, and it images better than my Ayre. If you still want a bit of the warmth of tubes, but in a quieter package with more extended highs and tighter bass I think it would be a great fit for your Pass Labs amp, particularly if that amp is your favorite. If your tube Quicksilver amps are your favorite, a more neutral preamp like the Ayre might be better, emphasis on might, but having not listened to your amp/speaker combo I cannot really say. And of course what I found to my liking might not be at all the same as what you like. 
 

So I’m back to encouraging you to audition several in your system before making a final decision. BTW, Moon Audio has a 30-day return policy on new Pass Labs gear. I suspect there are other dealers with the same policy. Return shipping is usually paid by you on a return. 
 

Hope you find what you’re searching for. 

@sameyers1

I assume you’ve found the solid state preamps you’ve tried are more neutral than your tube preamp, with tighter bass, a lower noise floor and perhaps more extended highs.

That’s on the nose. Exactly right. Often, what the tube preamp adds is preferred. But not always -- some recordings benefit from more the SS preamps additional clarity and upper register forthcomingness -- especially orchestral recordings. I like to hear the strings very distinctly, and sometimes this is not coming through with tubes.

Pass XP-12, eh? I’ll keep that in mind and perhaps be able to get one for a while from TMR or a local audiophile.

@mitch2
Fanstastic list! Thank you for taking the time. I’m saving this!
Surprised Bryston never crossed your path.

@jji666

I’m surprised at the lack of focus on the relationship between the preamp and the amp.

I’m assuming that those who have tried multiple preamps are assuming this as part of the evaluation, already, and don’t need to call attention to it. If not, then a lot of opinions here would likely be nullified if, as you’re suggesting, there may very well be a less-than-ideal match between preamp and amp at work.

It’s a good point above that whenever considering a pre-amp to consider how well it matches to the amp intended for use with it. Impedance matching is key. A high output impedance combined with a low input impedance will always color the sound and add distortion compared to same pre-amp with proper matched amp of higher input impedance. That’s just a fact! If not considered, one is much better off with an integrated amp where the design takes care of that for you. Tube preamps in particular tend to have high output inpedance and properly should be matched to amp of high input impedance, 10kohm or higher to be safe. Otherwise that clean neutral pre-amp goes to waste. Some might like the results still but you better at that point else the only option is change gear and try randomly again. Not an efficient, predictable  nor cost effective way to achieve desired results.

I’m trying to refrain from using a term “neutral”. I don’t know if my streamer, DAC, interconnects, cables and components downstream from the source are neutral. There’s just no way for me to possibly know that unless I can A/B what I am hearing at home with what it sounds like in the studio mixed by a recording engineer and played back on thar very same monitoring equipment.
All I can do is describe my ideal sound and tell you if I like a component or not.
Anyone stating Benchmark DACs. Preamps and amps, connected with mogami cables is a neutral setup - I don’t agree with it. But that’s just me.
I don’t mean to pick on Benchmark, but their electronics always sounded analytical and cool to me. Pass and Audio Research for example sound warmer and more to my liking. Does that mean benchmark is not coloring the signal but Pass and ARC components do? Not to me it doesn’t. Anyone saying anything is neutral, I call BS. That’s my take on it. Excuse me for being blunt.