If I'm looking for "Tube Sound", why would I put a Tube Pre in front of a SS amp?


I'm purposefully not specifying speakers as I would like to know in general terms the arguments for and against. So, to the degree that speaker characteristics could also influence the choice, please  explain.  FWIW, I do not know a phase angle from an impedance curve so I will try and educate myself as we go along.  Hopefully, others may benefit too.
finsup
Mapman&Atmasphere - pertaining to tubes and Class D - for the past 4 months I have been using an Oppo 105 (Exemplar Audio mod) as a preamp/DAC - this has a tube output stage - next in chain is a Rogue Audio Hydra power amp - this has a tube input stage followed by Class D - I have been VERY pleased with the results! By the way, this is feeding Spatial Audio M1 (open baffle) speakers 

Using my Manley Steelhead to drive newly acquired pr. of Pass 160.8s to my Avalons. Out of the box; the 160.8s had the best control of the bass that I have heard with the Avalons. Day (3) soundstage is wide, deep, layered. Midrange is to die for, highs are getting cleaner and starting to  shimmer. Bass is more articulated (micro & macro) imaging is superb. Last bit of palpable imaging and air that I suspect that I would get with tube amps is the only thing I could want yet; but superior bass control is what I will keep. I have been looking into NOS tubes. Not sure what various tubes will bring; but can hardly wait since this will be a 1st for me. So far I am definitely happy with my "divorce from Spectral " Instead of hyper details, I still have the details but everything sounds natural, No listening fatigue!! Sounds great at low, normal, High volumes. We are having our first "cool" spell in the Midwest. Amps keep listening room at 75 degrees!
I use a tube Pre (Ayon Eris) and SS Power Amp (Pass x150.8) and it sure works for me.

I note that Rogue Audio build integrateds that use tubes up front with Class D power modules - I have not heard them but they are well reviewed.
Well, I can offer an opinion of sorts. Having run all SS for years (Classe, Perreaux), eventually moving away from HiFi for a bit. Upon returning several years later, also started to experiment with adding a tube pre. First, a Quicksilver inserted with the Perreaux (not a good match), then a Bedini and finally a Levinson 23.5. I liked the sound (which is what matter, no?) I continued my quest while building my main system which now comprises an ARC LS17se and a Levinson 333 into Shahanian Hawks, the mating seem to do everything well from Rock to Jazz to classical and back to Folk.

Currently looking to upgrade the ARC to a 5se and move the 17se to my second system. So you can say I am hooked on the tube/SS combo.
Tube pre with a SS power amp is a great way to drive power hungry speakers and get that great tube midrange and high end and a solid bass.  I have a cary slp 05 and classe ca2300 driving some Thiel 3.7s.  Nice wide and deep sound stage, very natural sounding.  Not edgy or fatiguing at all.  I would recommend this combo (tube pre ss power) to any one.  Just make sure you pay attention to the output impedance of the pre and the input of your power amp.  Need to get a good match.  
I have tried a CJ PV12 (preamp) with an older class D NAD amp, but eventually removed the CJ because it imparted too much hum. Now I use a Chord DAC to drive the amp directly and it sounds good, but not nearly as good as my all tube fully balanced Cary preamp and Atamasphere amps - and I'm driving a 4 ohm speaker with a 16 ohm amp with no problems because I’m also using ZEROboxes. Recently, I added an ISOCLEAN wall outlet and power cords and I’m in heaven! I hear so much more detail and the sound is even more natural. In fact, the signal is so clean I have no overly warm tube sound at all. Amps are plugged directly into the wall and other gear is running on a standard outlet with an ISOCLEAN power strip.
Atmasphere, I'm not so naïve to think that that type of behavior hasn't been considered before or even after, but as my Jewish friends might exclaim; "What hutzpah!". 
Has anyone in this thread addressed preamp-power amp electrical compatibility? This interface is also important, like the power-amp/speaker interface. Solid state amps tend to have lower input and output impedances than tubed units. Your preamp's output impedance should be at least 10 times lower than the input impedance it sees in the power amp. Other things being equal, this would favor a transistor preamp into a tube power amp, unless the tube preamp's designer has taken steps to lower the output impedance to where it will work with the lower input impedance of a solid state power amp. There are many exceptions. I have one ss power amp with a 100k input which is similar to a tube amp I have. Check your specifications, people. You need to have good electrical matches between all components before assessing sound quality or comparing "tube" vs. transistor sound. 
The truth is that a tube pre cannot give you the tube sound If you use a SS power amp. The tubes advantages are 3D imaging, openness, soundstaging, and presence. The disadvantage is a coloring of the sound. If you use a SS power amp only a tiny fraction of the tube advantages + all of the disadvantages remain. If you want to have a tube like sound with a SS amp you have to use a single ended class a amp (sugden, first watt)
Currently pairing a Shindo Vosne-Romanee pre with a Viola Labs Symphony  amp driving Raidho D2.1 speakers. Rich tonality, detail, layering, large sound stage, emotionally involving...very hard to shut it down and get to bed at a reasonable hour!
While there's a lot of valid technical experience expressed here, I'd like to add a slightly different take on this topic.

In my experience, both varieties of amplification can provide fine sound, and cater to the individual preferences that each audiophile has --whether we are conscious of, or admit to them --or not.

Nonetheless I have heard exquisite sound several times and the cause is the care (and possibly experience) of the person who has assembled the system. These systems have been solid state, tube and hybrid (as is my own system, designed by Derrick Moss, another fine engineer).

My point, and something I believe is not adequately expressed in this thread, is that the matching of components is crucial to distinctive sound. It doesn't matter what flavors of ice cream you choose for your banana split; what matters is the way it tastes to Your palette. Nobody can either dictate that to you, nor determine what you like best; only you can discern what balance, or flavor, of sound best suits your taste.

Consider the opinions of those people whose other threads you respect; question the rest, winnowing what virtue or insight there may be for your inquiry. But approach our hobby/pursuit/addiction with 1) and open mind and 2) CURIOSITY. Wonder what you would like; don't make any assumptions, and don't listen too much to others. There is some great gear available.

And remember: the single most influential component in your system is your room, how you position your components (notice I don't only mention speakers) and how you treat your room to (re)produce sound with the greatest fidelity to your perception of musicality.

Complementarity, room treatment and an open mind will, if pursued rigorously and with patience, give you the sound that makes you fall in love with music over and over again. Isn't that the reward of assembling a system that suits our unique taste and preferences?

Study " Dampening Factor " and " Woofer Control ". I've run a SS pre in front of tube mono blocks , tube pre in front of SS amp . SS to SS , integrated SS and integrated tube. My current setup is a modern tube pre to low power tube . One of my former systems was a tube pre to a Bryston 4B ST to a pair of JBL 4312a's . It didn't need subwoofers ! When the drummer hit a drum you could feel it on your chest , that's where a high( dampening factor)  power amp shines . It also comes with a large dose of ear fatigue . So I have the JBL's and a pair of Klipsh Heresy II's . Totally different sound and power requirements . But they are both 12" woofer, 3 way speakers . Apples and Oranges . I'm currently running 12 WPC tube to a pair of Zu Omens . Every combination has good points and weaknesses . My systems are all under $8k. In the medium and high priced world it's a different game and I'm not qualified .  So as far as the sound ? MUSIC IS IN THE EAR OF THE LISTENER ! The gentleman that talked about being loaned numerous tubes , is a good example of what we do for each other in the pursuit of our hobby . I am fortunate to be friends with a former shop owner that has loaned me Modwright , Rogue and Acoustic Zen products . When he spent $5k on a new pair of JL subs , I was able to participate in the setup . When he obtained $3k in acoustic treatments , I was able to audition them at his home . I'm able to borrow his pro sound meter for my setups. And when my new preamp had a hum through my headphones , he loaned me his Seinheiser headphones . I'm a lucky guy and I try to help others the same way . I hope you meet someone in your town that can help you too. Great Question , and happy listening . Respectfully , Mike .
finsup-

the preamp (tubed or ss) is the heart of any system. You want the very best that you can afford. If you find that a ss pre& power amp is a bit too much, then a tubed preamp may round out your sound. A SS power amp is the best playback on electric guitar and bass guitar. 

As stated, I personally enjoy a tubed pre-amp w/ a ss power amp.
Wether it is an ARC or CJ pre-amp, this combo sounds the best to my ears.  ARC and Bryston is an excellent choice. CJ tubed pre-amps are very, very good w/ their ss power amps as well.  Most important of all, do  not forget carefully selected Cabling!
Not evaluations, Ralph, just some ideas. I don't like that table.
Unlike Thales in Ypsilon/Lansche/HB Cables system or Pear Audio top of the line table.
@inna , I don't see a video on the Purist site that shows a turntable. I hope you are not taking your evaluations from youtube seriously! From Peter Breuninger, who made the video I found on that site:
"I urge you, If you want your system to sound believable, these guys are some of the first to call."  You can hear him saying that right at the end of the video.

That was at the RMAF sometime in the last two years, in which case the turntable would have been a Kuzma Reference.

@unsound I've got no reason to think that the exchange I saw was not genuine.
Atmasphere, Care to hazard a guess as to whether what you witnessed was genuine and things fell where the would, or perhaps, it was just a dog and pony show, with all actors having already planned their respective exits, were encouraged to do so with a last shot at audio journalism?
By the way, Ralph, what turntable was in that Atma-Sphere/Classic Auduo/Purist Audio system that I saw on Purist Audio website. I thought that it had no real drive and as a consequence the sound was somewhat boring. Yes, that's youtube, not real auditioning, yet I heard many there and they all sound quite different. The best to my ear - Ypsilon/Lansche/Thales/HB Cables.
@unsound  Its funny about that- he knew others were in the room. As far as I know he's not been writing for years now.

@inna I don't agree but I am going purely from personal experience. As I said before, its a topic for another thread.

It all depends. Good sound is a team sport that includes not only all the technology playing together but the room and the listener so its always hard to predict outcomes.
Agreed!
Atmasphere, this account of a reviewer extorting a manufacturer is disturbing. Was this an established reviewer? Was the reviewer aware of your witness? If so, was the reviewer so arrogant not to care?
I heard this Gryphon story. Thinking along the same line, I would say that good reviews are equally unethical.
Atmasphere my ARC is SP16,  not latest but newer.   

It has its own flavor of sound like any piece does.    Dry is not an adjective that comes to mind with it.  

The sound is hard to distinguish as "tube" based I would say, which I like.   I do not have enough data points to say exactly how it would compare to others but the results of using it in my system are quite good I would say and not leaving me cold having heard many a top notch system including a few incorporating Atmasphere amps. 

Each really good system I hear sounds different but all share certain attributes including the ability to go loud and clear without listener fatigue during longer listening sessions.  

I run 3 good quality speakers in three different rooms off the system with the ARC.   The sound in  each case varies widely.   With either of my OHm Walsh speakers there is no edge whatsoever which lends itself towards very long enjoyable listening sessions.   With my Dyunaudios in a smaller room, there is more bite to the sound which makes things more exciting perhaps but some might find it harder on the ears over time.

It all depends.  Good sound is a team sport that includes not only all the technology playing together but the room and the listener so its always hard to predict outcomes.
I recall reading a number of articles on the Internet that indicate that while audiophile grade equipment seeks to avoid the distortion you are speaking of, other audio equipment such as some guitar amps seek to embrace it. So for the lay person like myself, while what you have indicated is very likely if not completely true in most cases, it seems conceivable that it may not be true in all cases. Meaning, while most people may perceive those higher end harmonics as irritating, I'd venture to say there are those that welcome it to some degree or another.  
What you read on the internet about guitar distortion is obviously inaccurate. This might come as a surprise, but its the guitar industry, not the hifi industry, which is why tubes are still in production after all these years. The reason for this is simple enough: when you overdrive a tube amplifier, it rounds the the waveform rather than chops it off. If you have a grounding in physics, you know that the corners of the chopped off waveform are higher ordered odd harmonics which are very irritating to the human ear. Guitarists prefer the rounded waveforms of an overdriven amplifier as part of their 'sound' about which they are quite picky!! I play in a band FWIW and am involved in the local music scene and have seen this first hand many times!

As it sits the guitar industry sells many more vacuum tube amplifiers than the hifi industry does- in fact they dwarf the hifi community. So they can dictate to the tube manufacturers what tubes are important. That is why there are EL34s, 6550s, 6L6s, 12AX7s, 12AT7s, 12AU7s and the like- those are all guitar amp tubes.

Now if a guitarist wants more 'bite' or 'crunch' to cut through the mix, often he or she will add a stomp pedal that makes a certain type of distortion. Some of these do indeed make more odd ordered distortion! But as any guitarist knows they have to be used with care to get the sound they are looking for, which is often an emphasis and not how they play all the time.

@mapman This is just me of course but I don't like the ARC preamps for the most part. It does seem like their later ones are better, but you don't have to go back very many years and the earlier ones seem kinda dry (indication of odd ordered content or lack of bass??) to me. My opinion only of course!

@inna  no worries! I agree that Rasmussen is one of the best Euro designers. I regard it as a great pity that Gryphon was the target of a disreputable reviewer here in the US some years back! I was in the Gryphon room CES at the time that the reviewer threatened Rasmussen that if he did not let the reviewer have the amplifier review sample for free he was going to trash it in the upcoming review.  That is exactly what happened some months later; that is part of why I feel that bad reviews are unethical. **That** is a topic for a different thread!!
@atmasphere 

Hi Ralph. To your point " What tubes do better than transistors is not make higher ordered harmonic distortions to which the ear is very sensitive and also perceives as irritating. That's not a matter of opinion its a simple fact and not a matter of debate."

I recall reading a number of articles on the Internet that indicate that while audiophile grade equipment seeks to avoid the distortion you are speaking of, other audio equipment such as some guitar amps seek to embrace it. So for the lay person like myself, while what you have indicated is very likely if not completely true in most cases, it seems conceivable that it may not be true in all cases. Meaning, while most people may perceive those higher end harmonics as irritating, I'd venture to say there are those that welcome it to some degree or another.  
Inna 9-28-2016
Atmashere, Nelson Pass and John Curl are not the best SS designers in the world. You forgot Rasmussen of Gryphon and also some other European designers. Besides, Vladimir Shushurin of Lamm makes hybrid power amps that are in essense SS.
You keep making incorrect statements from time to time.
Inna, note that he didn’t say "the best SS designers in the world." He said "two OF THE BEST solid state designers in the world" [emphasis added]. IMO that categorization is indisputable, and is not negated by the fact that many of their designs were intentionally implemented to a lower price point than most or all of the products of the other manufacturers you mentioned.

Regards,
-- Al
Atmasphere I have ARC tube pre-amp and Bel Canto ref1000m amps in my main system and newer BelCanto c5i digital Class D integrated amp in my second. They each sound quite different. The c5i in particular is smooth as silk with no edge or irritation whatsoever even when used with my Dynaudio monitors which can have a bit of a natural edge to them. The only fault I can find with it is the 60 watts do well but only go so far. It’s a fabulous device in a small reasonably affordable package overall.  Also has phono and serves well as a headphone amp with similar qualities. 
Atmashere, Nelson Pass and John Curl are not the best SS designers in the world. You forgot Rasmussen of Gryphon and also some other European designers. Besides, Vladimir Shushurin of Lamm makes hybrid power amps that are in essense SS.
You keep making incorrect statements from time to time.
@mapman I've regarded the Class D technology as a sort of rising star. I've yet to hear one that beats a good tube amp in my system but I've not heard them all by any means. I use a class D amp in my keyboard setup in my band and it works pretty well- better than the traditional solid state amp I used before- I get what you say about not having the same artifacts.

However that seems to play to my point which is to use a tube preamp and a solid state (class D) amp rather than the other way around. Is anyone making a class D preamp yet? A quick google search didn't find any examples.
Atmasphere I cannot explain why but I have also found good modern Class D amplifiers to not be "irritating" as well as some of the others you identify.

I’ve owned and heard some other SS amps as well that qualify.

Maybe the non irritating amp club has some other perhaps more anonymous or lesser known members these days?

Pass and Curl may be the trailblazers but it seems others have practically followed in their path in one way or another.

Nobody wants to buy an irritating amp that I know of so designers who do would have to be considered lacking if others have proven it possible. I’d hire someone else to design my amps for me if my guy did not do things "right".

Whatever the technical details my ears clearly tell me tube amps do not have the good sound market cornered these days even if perhaps that was true to a greater extent in the not so recent past.
But, lets be truthful and real hear. Tube is better than solid state? I don't think so. Nor do I believe that Solid state is better than tube.
What tubes do better than transistors is not make higher ordered harmonic distortions to which the ear is very sensitive and also perceives as irritating.

That's not a matter of opinion its a simple fact and not a matter of debate.

If you don't believe me ask Nelson Pass or John Curl, two of the best solid state designers in the world.

All designers worth their salt realize they won't get rid of distortion. The question then  becomes how to design the amplifier to make the least amount of the most irritating types of distortion. If you read their materials you will find that both of the above designers are very aware of this fact and it is their pragmatic nature that allows them to design some of the best solid state amps made.

Now what solid state does better than tubes is they can drive a wider range of loudspeakers while maintaining flat frequency response (although the latter is often a function of how much negative feedback the amplifier employs).

This is why I was careful to make my points in my prior posts the way I did. I did not say that 'tubes are better'- end of discussion. I pointed out what their strengths are in the context of this thread.  It is true that not everyone will like the facts as stated, but just because we don't like a fact does not change its reality. 


@mapman

I agree completely with your post with one exception, "expense". Personally, I believe it is expensive to make great sound at home these days

While I’m sure you would agree that whether or not something is expensive can be subjective, I think its fair to assume that everyone’s system is in one way or another dictated by the cost of their components. In my particular case all of my components were chosen wisely from the perspective of value (i.e. best sound for the money). If money were no object I would surely have a different setup, or an additional setup for that matter! :)

no the best tube sound when you actually put your speakers inside tube. to make it happen you definitely need to roll either one tube for both speakers or per each speaker.

minorl, Couldn't agree with you more. I believe HP said, If you haven't heard it; You don't have a valid opinion.  Go out and try equipment at your price point, both tube and solid state. I stayed locked into (1) system for years, and enjoyed it. Now I am moving forward and enjoying even more! Support brick/mortar dealers. Pay a bit of $ to have it shipped,if you can't make the trip. TRUST YOUR EARS! Only you can say what sounds great to you! You need to try and listen!






I’m with minorl on that.

Enthusiasts will obsess over whatever aspect they choose but the more I listen the more I tend to think people’s expectations and preferences are what matter most. That and the ability to assemble a system that works well for them accordingly.

Its not that hard or expensive to make great sounding music at home these days, at least on a smaller scale, as long as one knows what they want and how to achieve it.

Oh and most importantly have realistic expectations for example expect that all recordings sound different and no system will ever make them all sound top notch or any particular one the way you might prefer it would sound. Well maybe with enough digital processing in the mix if one really must make things sound the way they want them to rather than the way they are.

Now to do the same on a larger more realistic scale, that is harder. But it also can be done with either tubes or SS or a combo of the two, again as long as one has the know how needed to achieve it with a modest budget. The biggest challenge there is that the trend is for speakers to keep getting smaller and more expensive which makes it harder to achieve realistic sound levels with low distortion especially in larger rooms. Use of powered subwoofers can help more than ever there though.

I have to respectfully disagree with many here. In my humble opinion, It really doesn't matter whether the pre-amp or amp is tubed or solid state.  it matters what the listener likes to hear.

As I have written time and again, there are so absolutely wonderful tubed equipment.  However, there are also some absolutely wonderful solid state equipment.  Speaker-amp interactions aside for a moment (which is hard to do), a good design is a good design.  A good engineer is a good engineer. Unless one purchases a price is no object piece of equipment, each manufacturer has to compromise somewhere.

My point, is don't drink the coolade.  some people have preferences, and after demoing many pieces, they come up with their preference, that is fine.  But, my advice is to set a price point (said this time and again) for a piece of equipment and go find both tube and solid state equipment that the manufacturer says will mate well with your existing equipment and hear for yourself.

I have heard some outstanding tubed pre-amps and amps. Same for solid state.  But to say that tube is better than solid state of visa versa is just simply.....wrong.

Audio Research tubed electronics are wonderful and I own some.  Great stuff.  I also own Mark Levinson equipment.  I've heard Boulder equipment.  Very nice (ridiculously overpriced in my opinion). I haven't hear like priced Pass equipment of Gryphon, etc. 

So for a person to say that one is better than the other, implies that he/she has hear every piece within that price range and that simply isn't true at all.

Don't get me wrong please.  And please, do not attack me.  I like my Audio Research REF 3 pre amp in front of my Mark Levinson 23.5 amps. And yes, the 23.5 amp is still one of the best amps out there for the price.  But, I was finally, after two years convinced to purchase the Audio Research REF 250 amps, because they simply were wonderful.  They couldn't complete with the Mark Levinson on the low end, so my bass drivers on my Martin Logan Monolith III speakers still use the 23.5.

And if I can afford either a REF 5SE or REF6 pre-amp, I would grab it.  Audio Research makes really good equipment. 

But, lets be truthful and real hear.  Tube is better than solid state?  I don't think so.  Nor do I believe that Solid state is better than tube.

Pick a price point, grab some tubed and solid state equipment and hear for your self.

You may decide that a tube pre-amp out performs the solid state pre you compared.  Then, you will know the answer.

You may also find out that the tubed amp in your price range just doesn't do it with your speakers. Oh well.

This is where the fun starts.  It is okay to take someone's advice with regards to auditioning equipment, but please do not buy the theory that one design/configuration is better than the other.

it just ain't so.


enjoy

@atmasphere, Ralph, I did own an MP3 for a time. 

My post was intended to bring up the pleasure of tube rolling, nothing more. Cheers,

Spencer
@sbank you might try out a preamp that uses 6SN7s... once you hear what the 6SN7 does its hard to go back to miniature tubes.
Lots of great comments on this thread. One thing not mentioned is that with tube preamps, most use tubes that are:
- low in number 
- in sizes that plentifully produced by many manufacturers both past & present
- sonically different than other varieties of the same size tube
This leads to the potential sub-hobby of tube rolling. Hearing the differences between e.g. a Mullard vs. Telefunken is fun and interesting in itself, and let's one take the task of finding system synergy to an art form. My old friend and occasional poster, @mechans, shared a tiny portion of his great tube rolling knowledge with me, lending multiple pairs of 6922, 6DJ8 etc. to find out what works best with my gear. For those interested, it's fun and sonically rewarding with good tube preamps especially. Cheers,
Spencer
"However, if you really want to treat yourself go with tubes all the way. That way you get the additional benefit of reduced higher ordered harmonic distortion, which to the ear sounds like brighter and harsher, and is the thing with which transistor amplifier designers struggle. "

I would generally agree with the comment above. To me the really big difference AND big deal with tubes vs SS is the harmonic resolution AND that undefinable attribute of "presence" that the BEST tube designs really deliver that I rarely hear consistently with SS. I try to be fair minded, objective and balanced in these discussions but I REALLY agree with Atmasphere's comments. I have a good audio buddy, all tubes over the almost 20 years I've known him that has gone over to the "dark side":), tube preamp, ss amp, i mean superb SS. While I really like the presentation and at times it makes me question things, over time I notice that it just does NOT have the emotional connection to the music as good as it is. To each his own and remember this one simple point, it's all an illusion anyway, whatever floats your boat is most important, just listen and enjoy!
The reason to put a tube preamp with solid state is if you have to compromise and want the benefit of tubes, a tube preamp will give you smoother sound and more detail than a solid state preamp. There is no way to gloss that problem over downstream; once you've lost that low level detail its gone.

However, if you really want to treat yourself go with tubes all the way. That way you get the additional benefit of reduced higher ordered harmonic distortion, which to the ear sounds like brighter and harsher, and is the thing with which transistor amplifier designers struggle. Its true that those harmonics are minuscule compared to the greater amount of lower ordered harmonics typical of tube amplifiers, but the ear uses the higher ordered harmonics to calculate how loud a sound is and so is far more sensitive to them, in fact more sensitive than test instruments.

FWIW, its not beneficial regardless of a tube or solid state amplifier, to working with a speaker that is 'hard to drive', especially if that hard to drive aspect is low impedance. The simple fact is all amplifiers will make greater distortion if you make them work hard, and the distortion we are talking about is audible as a harsher and brighter top end. You can see this increased distortion in the specs of all amplifiers! IOW if high quality reproduction is your goal you are simply better off avoiding speakers that are hard to drive.


I have been a Spectral guy for 20yrs but am now parting ways. Spent time with new Spectral 30SV. Was "magical" for (1) week and then nothing but problems. I have owned a Manley Steelhead since '07 and it sounded good but used my Pass Xono more. Spectral gear is now for sale; so I pulled out a pair of Forte' 75w CL A monos and drove them directly with the Steelhead. Finally realize that the Steelhead IS a Great tubed phonostage! The Fortes' just don't have the power to drive my Avalons. Tommorow I will receive a pair of Pass 160.8s and drive them with the Steelhead directly. Also intend to "roll" my first tubes in the Steelhead. Will start to be able to weigh in on this discussion . Also have an audition of all CAT system in near future. I am rather new to "Forums" but Agon has been interesting, informative ,thought provoking and entertaining ! Keep it Up; guys and gals Thanks
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Want great tube sound? You'll need good speakers and a good tube  amp and tube preamp. When matched right, the AMP will make the biggest difference in sound. If you like tube sound, you may not go back to SS.
Agree with Eric's explanation, electrical compatibility between the amplifier and speaker IS most important as is the output impedance of the preamp being ideally suited to the amplifier. Beyond those two very important parameters much of the rest regarding some of the other comments is subjective. I would further comment that generally tubes are more ideal for use with a speaker having a higher and more stable impedance however there are tube amplifiers with quite low output impedances that can work with speakers with more difficult loads.

Tube sound these days varies quite a bit but in my experience I generally hear the effects of tubes to a greater extent when using a tube amplifier. Using a tube preamplifier with a quality SS amplifier, well the character of the SS electronics always reveals, to me at least, that I am listening to SS. Nothing wrong with that as each have their particular virtues and that is why no one can specifically answer your question but you when listening to a specific setup.
There are also hybrid power amps, Lamm and Ypsilon monoblocks come to mind. Lamm uses one tube. Of course, he also makes SETs and his preamp and phono stages are all tube. 
Perhaps one day they will invent something that will sound better than both in every way, perhaps not.
In my experience, all things being equal, a tube amp will impart more of a tube sound to the presentation than a tube preamp, but some speakers need ss power to drive them and in that case there is only one way to go.