solid state vs tubes

Mapman, I suspect that in narrow technical terms there might be something to it, but I wonder if it would hold up in broader technical terms. More importantly, I agree with you, that in practice it might not matter.

Unsound,

I think speakers are generally voiced to sound a particular way with certain kinds of amps and vice versa. I suspect tweaking the impedance load in any given case would change the sound and present a better opportunity for the right amp to now deliver better sound. I doubt that in practice though this would always necessarily be the end result. Its all about amp/speaker synergy which can be achieved via many combos, warts and all. Providing a technically better playing field as a higher impedance likely does does not necessarily assure better results.

Mapman, I am not convinced that a higher impedance is a technically better playing field. In fact I believe the opposite to be true.

Maybe.

In general, I believe higher ratios of input impedance on a device downstream to output impedance of the device upstream to always be a good thing, all other things aside.

Of course, in reality you can't just conveniently focus on on e factor and push all others aside, so who knows in any particular case. No one ingredient alone makes for good soup.

my original question has not been answered:

has anyone participated in a "blind" test comparing a solid state amp to a tube amp and been unable to discern the difference between them , say 7 out of 10 times ?

MrT:

That was not your original question.

Which is it?

Mapman, One of the advantages of ss amplification is it's inherently low output impedance, low speaker impedance speaker loads are almost never a concern. There are some, that believe that the best results occur when impedance's are more closely matched (Jeff Roland?) rather than having a low to high ratio. I suspect it might have more to do with application. It appears to me that it is much easier to achieve better bass response and steadier impedance loads in lower impedance speakers than in higher impedance speakers.

I have had many tube and solid state components , I've slowly gone all S.S. . The last 3 to 4 years tube and solid state has nearly reached convergance , at least in the higher end . The break down rate on the tubes was only slightly higher retubing for my preamp was $ 550. per year , my power amp $2200. per year , the odd time you would get a bad tube and have to start over . Go over your recommended tube life and things would start to go very wrong , so I was listing less to save tube life , also the heat from the tubes in the summer meant reduced listing time . I loved my tubes , but I have found S.S. gear thats equally as injoyable , although somewhat more pricy up front . M

"The break down rate on the tubes was only slightly higher retubing for my preamp was $ 550. per year , my power amp $2200. per year"

Wow, that's scary.

The tubes in my ARC sp16 are coming up on 2 years with a lot of play. I have had minor noise issues that I have alleviated by shuffling existing tubes, but I think the time is coming to replace all. From ARC, the cost of doing that is about $30 a tube or $180 dollars total for 6 12AX7s.

I really like the ARC but if I were shelling out hundreds a year just to retain the good sound, it would probably be out the door and back to all SS for me.

So many possible responses.
Isn't it true that when connecting to the various taps on a transformer that you are using more or fewer windings? Won't that change sound more than the load variations to a SS amp?
I like the talk of sensitivity and efficiency as different things. Also on the plate is impedance...and not just a single nominal number, but the range, along with min / max for any given speaker.
Than again, nobody has yet mentioned phase. I am told that Harbeth makes LS 3/5a type speakers and though they are about 83db sensitive, make a wonderful match for tube amps. Benign phase and moderate impedance range are key.
My panels should work with tubes, as well. Reasonably flat impedance curve and no wacky phase problems.

Naw, I think the concept at least is pretty simple. Compatibility / synergy can be chosen electrically. Magic happens when you get it REALLY right. It shouldn't take a lot of money for a good, basic, solid, good sounding simple system. No need to spend a bundle on cables, either.

Again, damping has come up. And nobody has mentioned speaker 'Q'. What role does the design of the speaker have in all this? Can't a critically damped speaker produce fine bass in an 0 damping factor system? I suspect so.
You don't need a DF of 10,000 to get good bass 'control', which is one of the red herrings of audio. A speaker with 'Q'=1.25 will be sloppy almost no matter WHAT you do.

Unsound, Paul Speltz who makes the ZEROs has a letter from Steve McCormick, in which Steve asserts that his amps, which have no problem with 4 ohms at all, sound better driving 4 ohms through the ZEROs.

Upon hearing about this (which was about 2 years ago) the next time I was at CES I asked about this subject with several of my friends in the industry who make transistor amps. I was surprised that there was a consensus amongst them, that I can paraphrase (this one stated almost verbatim from Edge's Steven Norber) 'just because it is comfortable driving four ohms does not mean it is sounding its best', this specifically in relation to 16 ohms.

One thing that you may not be considering is the role of the speaker cables, which is critical with 4 ohms but not so at 16 ohms. For example if you do the math, you find that no matter how high the damping factor of the amp, there are no speaker cables that will allow the amp to express anything more than 250 into 4 ohms.

In short, in high end audio there is no compelling case for 4 ohms. Its bad for tubes, bad for transistors. How this might relate to MrT's inquiry is that his job would be easier were he to use a higher impedance speaker.

BTW, I do concede that in my comments 'all other things being equal' is a serious caveat. They never are. Because of that, it took a long time to figure out how important this issue actually is.

Finally, I would like to point out to MrT an issue that must be considered: speakers that are designed to work with transistors may not work with tubes, and vice versa. This is an old conversation, that of equipment matching, but touches on a larger subject:

http://www.atma-sphere.com/papers/paradigm_paper2.html

Atmasphere, auto-formers aren't a new concept. The only ss amplifier I know of that includes an auto-former appears to do so in an effort to adapt to an otherwise speaker mismatch. If auto-formers were of such benefit and without deficits, why wouldn't they be included in all original amp designs? Or if not amps, why not original speaker designs? Of course we don't listen to amps, but speakers powered by amps. That para-phrased statement of Mr. Norbert is quite a bit different than claiming that ss amp sounds better into higher impedance loads.
What aspect of the speaker cable is this attributed to?

Unsound, in this case Mr. Norber was telling me, as did the other manufacturers, that indeed their amps do sound better into higher impedances, despite making less power.

The Mac autoformers are used to load the transistors at a lower impedance if I recall right, quite the opposite of what we are talking about. I have to tell you, I was quite surprised to find that the ZEROs have a benefit to transistor amps in the same way that they do for tubes, although when it was pointed out that this has to do with the behavior of the output devices when more current is put through them, it makes perfect sense.

With regards to speaker cables, it appears to be simple DC resistance.

hi mapman:

the issue of discerning the difference between a tube amp and a ss amp, ceteris paribus, is of great interest to me.

if i can be foooled or cannot tell the difference between a ss or tube amp as party of a stereo system, why have the tube amp.

ralph: i thinki the issue is planar vs cones , not impedance.

it may be harder to tell the difference between amps using cones, than panels, regardless of a con designs impedance curve.

in my case , a planar owner, i think it is easy to tell the difference between ss and tube amp. electrostats and ribbons do not have the same impedance curve, yet they are -panels.

i have heard rowland and avalon sound very pleasant , when combined, but i have yet to hear a panel speaker with a class d or ss amp drive an electrostat or ribbon, or planar magnetic exhibit a well beheaved upper midrange, treble response.

i realize it is preference and i expect that finding a ss amp that will be livable is almost impossible. i have no illusions, but will not give up the quest, as yet.

Mr T.

That's fine I think you need to state the question as might your speakers sound tube like with a ss amp. Nothing else really matters if that is what you seek.

I personally think it is possible with some SS amps, maybe even the better Class Ds. You might want to through some tube gear up front in the pre-amp or source in order to keep things leaning more towards the pure tube sound, but I'd be willing to bet you can do it with a SS pre-amp and maybe no tubes at all.

I would not hesitate to suggest trying the Carver m4.0t that I used with mg1cs for years with no real tubes. A used one would only cost a few hundred. Or maybe even a m1.0T which is the amp that was voiced to sound like the CJ reference amp. My only reservation with this combo was that a sub was needed for the low end to be competitive with truly top notch systems in that regard.

Atmasphere, silly me, I forgot about the Macs. I was referring to the Pass M2.

Interesting read with lots of opinions but there is more to it than just the amp and in the end just that opinions and really no right or wrong.

That being said I replaced my CAT JL3 Sig. MKII mono blocks $40K with the new Bryston Squared 28's less than half the list price and I'm very pleased, I have not found any other amps no matter what price and/or design and I have had allot of world class pces making me want to change, my speakers are MBL 101E's. I'm after getting the most out of my speakers.

I know of others whom have been trying these amps and have been pleasently surprised also so you might want to try. My preference is haveing solid state paired up with a tube pre, I'm currently using a VAC Sig. MK2a and truely enjoying.

Another member said this;

09-26-10: Bryceeboy

The first time I ever got what the SET group was raving about was when I inserted the 28B Squared into my system. I am a tube guy through and through but when I placed these in my system nothing had come close in the past. I own Soundlab A-1's which are a bear to drive but these things can make them growl or purr like a kitty. Great amps IMHO! Good luck.

Dev,

In your case those mbls would pretty much dictate SS amplification.

BTW you are a lucky guy. Nothing does 3-d imaging of large scale classical recordings as holographically as the larger mbls I have heard.

i will repeat, i am not looking for tube-like per se, but rather to be unable to detect the difference between a ss and tube amp, driving a pair of planar speakers.

i might be able to find a ss amp which exhibits tube like characteristics, yet it may also exhibit ss aspects. that is not my goal.

i'll give a crude analogy.

suppose i have an apple. i like to find another fruit that tastes like an apple that is not an apple.

from what i have read so far it is virtually impossible.

MrT, there was a time when planars ruled the roost when it comes to resolution. That time has passed- there are a good number of cone systems now that easily compete with the best planars.

However, my comments were more the point that if you had a 16 ohm planar, any amp that you have tried so far would sound better on such a speaker.

IMO, one of the most musical transistor amps that is also reasonably priced are the zero-feedback Pass amplifiers, particularly the First-Watt amps. The Ayre is another good choice. So far the best I have heard, better than most tube amps, is the Ridley Audio amplifier. Beyond that, most transistor amps that employ large amounts of feedback are going to sound a lot more like each other than they will like anything else, including tubes.

I should point out though that the 3 amps I listed also are known for making heat, as the simple fact of the matter is that class A operation is part of how these amps manage to sound right. In fact, the Ridley employs a heater to raise and regulate the heat of the output devices. So other than occasional tube replacement, IMO you might as well have a tube amp, if quality sound like real music is your goal...

LOL, Atmasphere, I've got hand it to you, you do know what you like. The Ridley runs hot and hardly increases power much at all into lower impedances. Just like yours.

Unsound the zeros have a 60 day trial period so you can try them on your own system with no risk.

"i will repeat, i am not looking for tube-like per se, but rather to be unable to detect the difference between a ss and tube amp, driving a pair of planar speakers."

I don't think anybody can tell what you will or will not be able to detect. Only you know what you hear and like.

All I can add and then I'll check out is that good sound is good sound, regardless of the technology used to achieve it. And only you know what good sound means to you. So don't be hung up on it must sound like this technology or that. Just do your homework, try some good SS amps and hear for yourself. If you really want to ditch the tube amps bad enough, I am certain you will. Otherwise just live with the tubes for better and for worse.

MrT, I have one word for you...Spectron! Or even better for your planars two words...mono Spectrons!

Spectron or better mono's?

I finally heard these (mono's with all options) in another members system paired up with Analysis Audio Amphitryon panels who has been raving about his sound for a while now in other threads so I was very anxious to hear, well I did and I did not think much of the set-up, I actuatly felt sorry for the guy. Now before the bullets start flying it could have been something else within the chain but it was very disappointing and I couldn't find anything to comment positive on. A good friend went over to this members place at another time because he really wanted to hear these Greek speakers as they have been raved about and having a conversations afterwards also had nothing positive to say except he felt it could not be due to the speakers themselves but someting else farther up the chain.

How do you tell someone who is so convinced their system is all that when by far it isn't?

Dev,

There is a profound lack of criticism in audio, which is even more extra-ordinary considering the prices. I will not comment on Spectron, not having heard it, and not having an interest in hearing it.

Of course, your perception is not valid because of issues related to burn-in, cabling, speaker matching, component matching, music selection, or speaker positioning. Take your pick. And even if you went through all these items, in your own home, for every piece in the world and decided you didn't like it... Still, someone, somewhere, in some system might find it heavenly. Ergo, any piece of audio, once constructed, is infallible.

I wish people would come out sometimes and say, "It sucks". That would make this hobby much more simple.

I think in the next 3 to 5 years Class D gear will over take tube gear (Sound Wise)

Rtn,

The problem with that is a lot of audio other than clearly audible distortion or noise, most of the rest is subjective. Otherwise, in the end, the owners opinion is really all that matters.

Of course its still always possible to discuss what one hears civilly in that almost everyone still has something that they can learn.

Atmasphere; I owned the ZERO gold ic and sp's. They were ok. I was never really thrilled with them. You spend that kind of $'s, even second hand, you should be ecstatic. I never noticed the improvement you speak of. I am not saying it did not exsist. They are very well made, as they should be, but very very stiff. Tough to install and feel comfortable with their instalation. Of couarse this is all secondary. It is the preformance that matters the most. Getting back to what I believe the original point of this post, SS and Tube. No simple answer, but prior to my exsisting system I had Krell evo 202 and Evo 600's. I still had the Zero's which were only change recently. The krell which I had for 2yrs were shipped the day before the Vtl arrived. So not side by side but pretty close. Many of the attributes are very close. Bottom end, mids and high's very simalar. The main differance to me is bloom. A wider sound with a slightly differant(deeper wider) stage. I will say the biggest change from any replacement of equipment in my 2 channel anolog setup was the cartridge(the source). An immediate(instant) change. In my case for the BETTER! The largest bang for the buck. At least in my system. Of course, it was the last change as well, so that may have something to do with it. But much more noticable then cables, amps or pre-amp at this level anyway. Having said that, I love my tub set up, down sides and all.

The best speaker you ever heard?
08-29-06: Hifisoundguy
Bose Acoustic Wave System series 2 !
Hifisoundguy (Reviews | Threads | Answers | This Thread)

10-02-10: Hifisoundguy
I think in the next 3 to 5 years Class D gear will over take tube gear (Sound Wise)
Hifisoundguy (Reviews | Threads | Answers | This Thread)

Yes with your Bose Acoustic Wave System series 2!!

10-02-10: Koegz
Atmasphere; I owned the ZERO gold ic and sp's. They were ok. I was never really thrilled with them. You spend that kind of $'s, even second hand, you should be ecstatic. I never noticed the improvement you speak of. I am not saying it did not exsist. They are very well made, as they should be, but very very stiff. Tough to install and feel comfortable with their instalation.

Koegz, Atmasphere wasn't referring to cables. He was referring to Zero Autoformers, as linked to on the left side of this page.

Best regards,
-- Al

"I wish people would come out sometimes and say, "It sucks". That would make this hobby much more simple."

Well, there are quite a few vinyl advocates that say digital sucks so there is one example for you. Simpler now?

BB, Good point. Perhaps I was being a bit melodramatic. I would like to see something more like: It does A, B, C. But it does not do X, Y, Z.

"I wish people would come out sometimes and say, "It sucks"."

I agree with you Bostonbean, but it's more easily said than done. I have friends and acquaintances that would receive criticism of their wife and kids more kindly than they would their audio systems. I think it's absolutely crazy, but I've seen one friendship cool substantially after the suggestion of a subwoofer; and I've seen another friendship actually end after a guy, who just couldn't take it anymore, asked the host if he could watch television.

Wow! this thread will go on for ever because it is a subjective discussion/argument. Lets take away the tube and solid state fan boys that won't ever accept that the other can be as good or better. Some people are in a particular corner because that is what they believe period. People vote republican or democrate many times, not because the candidate is better than the other, but because they refuse to vote any other way. same is true for tube vs solid state arguments most times. Good Engineering is good engineering. If it is designed and constructed correctly, it will reproduce the electronic signal as it was designed to. Remember those words. as it was designed to. Does the engineer seek to reproduce the signal as accurately as possible or do they seek a particular sound? Many times it is the sound, not signal accuracy, and people develop a personal taste for what they like and totally throw out accuracy. I have compared top of the line tube equipment (apples to apples) with top of the line solid state and as with any piece of equipment designed by different people, there will be differences in sound output. But, I can say as an engineer and as a music lover that they both (excellent top of the line tube and solid state) sound wonderful and I would take either. As I have written many times, take your favorite well recorded music, sit in a room, listen to your music on a tubed amplifier, then remove that one and plug in a solid state amplifier and listen again. compare apples to apples. A $5000 tube amp with a $5000 solid state amp (just make sure they are in similar price and quality range). Designers have compromise points based on the budget and price range of products. That is why price, and quality ranges are so important in comparisons. You can't reasonably take a Audio Research REF 610 amp and compare it with a Yamaha $700 amp and think they would be even close. Don't play with cables or any other item. Just amp to amp and see (listen). It will come down to your personal preference. Don't allow your thinking to be biased by other's ideas or preferences. Listen for yourself. You will find that a good engineer/designer can do tube and solid state equally well. Do you honestly think that Nelson Pass can't design and build a top of the line tube amp? Same with Tube designers doing solid state. Listen to the music. Love the music. Does it sound real? If not, why? First is probably that it was recorded badly. Which is the case most times. Just a bad recording and certain equipment is very forgiving and will not reveal the inaccuracies. Or they are designed for a particular sound. Other equipment will reproduce the signal as it was recorded and will reveal terrible sound. But, it may not be the equipment, but the recording. There are many things going on, not just one thing. Talk to knowledgable friends, listen to equipment and music and have fun. Borrow equipment from people and stores and listen.

minod, you present some lucid arguments but you neglect to discusss the central concern of this thread, nameley the posssibility that in a given stereo system, a tube and solid state amp produce a "sound", which makes it almost impossible to detect the difference between them ?

I think Nelson Pass chose SS because he felt there were already alot of really good sounding tube amps, the trick was to get SS to sound good and he wanted to take on the challenge - don't know whether his stuff sounds tubelike or not, though he often describes the ways in which his circuits are similar to tubes in their simplicity compared with other SS designs. Mrtennis, I have no idea if there will ever be a time when you can detect the difference between SS and tubes, too subjective (yours) to know, but it does seem that there are at least some audiophiles that would be hard pressed to detect the difference and know which was which.

Thanks for the correction Mrtennis; However, what I was trying to say (among other things) is that unless the designer/engineer used the same specs, layout, parts, construction, wiring, grounding, etc. in designing the amps, it won't matter if they are solid state or tube, they will absolutely never sound the same. Apples to apples. Two different 50 WPC tube amps will never sound the same unless they are the same amps. Same for solid state equipment. You will always detect a difference in sound from different equipment, even if they have the same specs. The transfer functions (don't ask) of each piece of equipment are totally differnt. That means that gain, phase, etc. are different based on the design and circuitry. That is what some designers tried to do in the past. Copy transfer function responses of high end equipment in the designs of their own. So, if we are talking about amps, and not pre-amps. First, what speakers are we considering? What is their impedance characteristics over frequency and power? Knowing that, what amps can handle that? If the speakers loads are very difficult, then only a few amps can handle them correctly without oscillating or blowing up. It totally depends on what the engineers intended in the design of the amps. Input impedance, sensitivity, gain, output impedance, load handling characteristics, power, voltage, phase, price, efficiency, etc. All of these must be taken into consideration in the design and as I mentioned earlier, depending on the price point, compromises must be made. So, the short answer is no. No tube amp will sound like a particular solid state amp or visa versa. Even two tube amps don't sound the same. It will ultimately come down to what type of sound you want. Real, altered, bright, fast, etc. This is why the used market is so great. There will always be the next greatest and better piece of equipment coming and someone will absolutely have to have it and will sell their other equipment to make room. I know a person that sold their Mark Levinson 20.6s because he doesn't have room for his top of the line Boulder amps and his Audio Research 610s. So, even though the 20.6's are better still than just about anything out their, they had to go and if I had the inclination, I would grab them. Solid state or not. That is not to say that their aren't any tube amps that are just as good or better, but you are now in the upper ranges of high end. you want great sound? take a listen to be top of the line Boulder amp/pre-amp. I haven't heard a tube set up better. Close or just as good? maybe, but better? I don't know. enjoy the music. Enjoy the race.

Minorl, not to put to fine a point on it but the idea of designing an amplifier to pass a signal without distortion is being heavily glossed over in your arguments, which, other than that, I find myself in agreement with.

The problem lies with the fact that our ears, regardless of the individual, use a set of common rules that govern our perceptions. Now really, that is not a problem except that the bench tests that are commonly used are for the most part not devised with these perceptual rules in mind. So as a result, a common experience is that an amplifier that measures well does not sound good, because **in the attempt to measure well, the human perceptual rules are being violated**.

So it is not true to say that the amplifier that has the 'lowest distortion' will be in fact the amplifier that actually *has* the lowest distortion; the two can be quite different! Often 'higher distortion' amplifiers (as measured on the bench) are lower distortion when subject to the reality of our ears.

In short, the bench measurements come off as an example of the Emperor's New Clothes. Our ears OTOH, are the real thing. Now it is a simple fact that tubes more closely obey these perceptual rules than transistors do, that is why it is so hard to find the transistor amps that really sound like music. However, and I point to Nelsen Pass as an excellent example, when you find such an amplifier it will be because the designer is also looking at how our ears work.

Atmasphere,

Does what you say about loudness cues, our ears and how amps are designed apply mainly in regards to how amps distort?

Loudness cues conveyed by certain harmonics is a natural occurence, correct? What if say a SS amp conveys these cues accurately as they would be if heard live? That may not be as pleasant as them not being conveyed accurately say as a result of tube amplification, but that does not make it wrong, does it? If not clipping/distorting, what if a good amp just conveys what's there accurately, and measurements support that this is what is occurring?

If an amp is not clipping and is fast enough to deliver transient peaks accurately, some might perceive that as a good thing I would think rather than relying on the amp to filter or transform the sound in a manner that makes it more pleasant or digestible. That does not occur when listening to things live. The sound and the harmonics that comprise it are delivered without benefit of amplification or filtering devices to shape it into something more digestible to our ears, for better or for worse.

Mapman- I won't speak for Ralph but I think you are missing something important here. We are not talking about an amp that is filtering or transforming anything. The issue here is that, supposedly, we perceive certain kinds of distortion (can't remember if its odd or even harmonics) as more harsh or objectionable than others. So, (to make up an example) 0.10% distortion of those harmonics sounds "worse/louder" than 1% distortion of those to which our "ears" (actually brains, I think) are less sensitive. Remember the numbers are made up and I also believe that even within the odd vs. even harmonic dichotomy, there are certain specific harmonics to which our ears are more sensitive.

I only say "supposedly" because I don't have any independent knowledge of the science nor am I an auditory physiologist or experimental psychologist. However, this explanation is consistent with what I remember from my long ago undergrad days about differential response to various kinds of stimuli. This also jibes with what I have heard w my own ears; that ss amps that measure 1X% THD do not, in many cases, sound as good as tube amps that measure 10X% THD.

If your hypothesis is that minimizing THD is an important design goal for an audio amplifier, then many would say that, based on their listening tests, your hypothesis cannot be experimentally verified. That statement does not deny that minimizing distortion is not an important design goal, just that minimizing THD (which is measured in a very specific way) cannot be shown to be an important design goal.

Another way to think of this is that it may be a case of "if your measurements don't match up your experience, maybe you're measuring the wrong thing." In this case, measuring THD may not be the right thing. I think Ralph would suggest a weighted measurement that assigns the most "weight" to those harmonics to which we are most sensitive. Call it WHD (Weighted harmonic distortion) or what have you. The relative weight assigned to each harmonic would have to be determined experimentally, in order for this concept to be applied in practice. When you think about it, THD is actually a specific type of WHD, in which the weight is "1" for each harmonic.

I'll stop now before I dig myself in too deep.

Swamp,

It seems much of the argument revolves around how amps distort, in particular how they distort when clipping occurs.

My understanding is that no amp should normally be run in a manner where clipping occurs. If it does occur, then a different and better suited amp for teh application is needed.

What happens when clipping is effectively taken out of the equation with SS? It seems to me that most issues I detect with GOOD SS amps sounding harsh or distorted can be attributed to clipping occurring or some other abnormal operating scenario that perhaps affects transient response, not a normal one.

There is a technique in image processing called contrast stretching. Essentially it means if you clip off the extreme bright and dark extents of the image or picture, you can then stretch out what remains and often show subtle contrast details that are otherwise not apparent. Seems to me soft clipping as found with many tube amps and even some SS, operates similarly. Peaks are clipped in a softer manner that is more digestible to the ear. That allows volume to increase to higher levels than otherwise. Now more subtle variations can be heard in the rest also.

Now take clipping out of the picture by using an amp/speaker combo capable of achieving this at realistic listening volumes. Peaks go louder sooner (though are not cliped or distorted necessarily) and, ouch loud things can hurt now perhaps sooner rather than later because, hey those peaks are loud as they should be. But you now may need a really good ss amp with excellent resolution and detail in order to actually hear the subtle details because, hey things are not louder overall now so subtle differences in teh sound are harder to discern, especially if you do not have good ears and or a very quiet listening environment where what is played can be clearly heard.

Am I off somewhere in describing things this way?

As a corollary, here are a few factors that might push one into the stereotypical (no pun intended) soft clipping/tube amp camp rather than the stereotypical SS one.

1) recordings must be played too loudly in order to hear subtle details (increasingly common these days compared to past with many modern loudness wars recordings)

2) hearing/ears not what they could or used to be (typical as we grow older)

3) too much background noise to discern the low level details that might be heard otherwise

Please not that I do believe that, as Bob Carver seemingly demonstrated, SS amps can tweaked to sound like a tube amp if you have a way t accurately measure the differences and you have tthe knowledge to know what amp parameters or characteristics need to be changed to accomplish the goal.

As a consumer, the trick then is to do you homework and find a SS amp that plays better in this scenario than most S amps, and more like typical tube amps.

Mapman, I am **not** talking about clipping, although it is true that in clipping, tube amps generally make less odd ordered harmonics than transistors do.

What I am talking about is the fact that when you use feedback to control distortion, the price of the feedback is distortion of the loudness cues (5th, 7th and 9th harmonics). Not by much, but as I mentioned before, 1/100th of a percent is audible. It seems crazy to think that the ear is that sensitive, but after all, it has to be sensitive to *something* and this is the mechanism that we use to determine the volume of a sound! So when you see amps with very low THD, its likely that this mechanism has been interfered with.

The result: the SS/tubes controversy since SS amps usually use a lot more feedback than tubes do (which can be built with no feedback at all)- IOW tubes more closely mimic the rules of human hearing, and so make much less of these particular harmonics, even though they often make more of the lower harmonics (which the ear finds less objectionable, though they are often credited with the 'tube sound').

Its not so much that I prefer tubes, what I really prefer is amps that don't violate human hearing rules. So that is an amp without feedback, more than it is tube or transistor.

Now, without feedback, it might be better to have either a higher impedance in the speaker and/or a flatter impedance curve, but if that is the price to be paid it seems small if it is the difference between something sounding like a stereo and something sounding like real music.

Hmm, not sure I see a consensus that use of negative feedback is always categorically a negative. It seems to be debatable at best.

The soft clipping characteristics of tube amps in general seems to be pretty widely accepted. Soft clipping means that dynamic range is restricted to some extent as I understand. That means loudness cues are reduced relatively, all other things aside, as well, right?

The discussion here is equally facinating and confounding. Because the arguments are great. But, lets remember that original post was about whether in direct comparison between tube and solid state amps the difference was non discernable. Atmasphere as usual presents a well thought out technical discussion regarding the benefits of tube amplification and some drawbacks for solid state. As I pointed out, with well engineered/designed tube or solid state amps, I'll take either because a correct well engineered design is just that, regardless of whether it is tube or solid state. Most of the arguments (not all) against solid state really stems from the mass produced stuff produced in the 70s and 80s. It wasn't really terrible, it was just not really good enough for serious listening, but background music. I have several systems in my home that are used specifically for background music when I'm not doing serious listening. However, Bob Carver was correct in that if you give a good engineer enough time and money, they can make an amp sound like the best made. Just copy the transfer function of the best. But, solid state distortions vs tube distortions, come down to how hard the engineer wants to work to eliminate the worst kind of distortion and leave only distortions that aren't bad. Both in tube or solid state. Nelson Pass has an excellent article on his DIY Pass Labs site about this very topic. Wonderful reading. Compromises abound in this industry. How much time and money does the engineer have to work with? If unlimited, you will have a solid state amp that no tube amp can touch and the same can be said for a tube amp. I have heard some not so great tube amps and some not so great solid state amps. I have also heard some wonderful tube amps and some wonderful solid state amps. sooner or later I'm going to hear some Atmasphere tube amps and I bet they are absolutely great and I would be faced with the decision to go broke again for a short time or not. But, even when I'm sitting worrying about how much money I just spent, I ultimately end up smiling when I realize that the music is absolutely wonderful and life is good. First thing first. I know good music when I hear it and I can tell a bad recording or simply bad music when I hear it. I played classical violin (first chair), oboe, sax, and many other instruments. I know Jazz, R&B, rock, classical, etc. I know live unamplified music and have heard very good amplified music. So, I know what a real symbol sounds like. So, my point is when you sit in front of that special system and listen to music, does the singer come out on stage? can you see the stage? where is the piano?, drummer, etc? can you see it? how deep is the stage? If you can't see this, then 1) either something is wrong with your system, 2) something is wrong with the recording or a combination of both. but, you absolutely should know that something is wrong. I am a advocate of making friends with a very good stereo equipment shop and on occasion go in and listen to their best system (that you know is good) and reacquant yourself with what a great system should sound like, so you will know what is wrong with yours and work slowly in fixing (a piece at a time) yours. It takes years, unless you have a lot of money now. Enjoy the music. Life is short. Equipment come and go and does slowly improve over time. But, don't marry the equipment, marry the music. I really enjoy reading your threads.

enjoy

Minorl, all good points, but, I do agree with Atmasphere on the point that in many instances one technology will work better than the other, and visa versa. In such instances, one or the other can not be swapped in and out and be expected to work at their best in such varied systems.
Obviously, this often compromises direct comparison, and one has to ultimately decide what pro and cons of the total system, best suit the individual consumer.