Tubes vs Solid State - Imaging, Soundstaging, 3D

Neil Diamond? Now I'm REALLY upset...last word from me on the dearly departed (from the forum anyway), ALOHA!

I thought I'd get more hiss than I do from my Jolida, but it's actually less than what I had from my previous SS amps...including some well regarded designs. Again, maybe I'm lucky. You have to stick your ear next to the tweeter to hear any noise at all and except for LP surface noise, all is quiet on the Eastern front, except in my guitar room where it's noisy as hell and I just ignore it.

I'll respectfully disagree with Mapman 's assertion that modern implementation of NFB has been improved. When I hear amplifiers that utilize generous levels of NFB it's very apparent in that there's an artificial character quality of the sound. I just don't hear the same naturalness or realism of instruments and human voice. Simple tube circuits that omit or use minimal NFB are much better sounding and more convincing of reality.

I recognize that this is just my observation based on listening to many different amplifiers over the years. Mapman I certainly appreciate your satisfaction with your current class D amplifier and congratulations on your happiness with them. I acknowledge that we just hear things differently and may in addition have very dissimilar listening priorities.
I haven't come across a SS or class D amp that can approach what the well implemented no NFB tube power amps are capable of. For sure I'm in a minority as there are far more owners of SS amps compared to tube.
Charles,

Hi Charles,

No need to agree, but I suspect its a stretch to think that while technology has progressed in most every way greatly over the last 40-50 years, amplifier design has remained stagnant.

Whether or not a good modern CLass D amp with NF sounds as good as a tube amp or not is a different story.

I'd agree that they are not likely to sound the same, and each is likely to perform best in a completely unique and different system.

I've used many a good sounding "high end" system for reference in putting my own together, including many very good tube amp based systems.

I could likely not afford the tube amp I would need to drive my preferred speakers the OHM F5s to their max, nor the power bills that woudl come with it.

So my case is somewhat unique in that the OHMs are a somewhat unique design and case to optimize. The Class D amps do it though and in manner that brings the best of both worlds to the table in a way that works for me.

If I had the time, money and patience to deal with the tube amp I would need for similar performance with these speakers in particular, I would be tempted, but that is an alternate reality for me.

No one amp, speaker or anything holds all the cards. Each has different strengths or weaknesses. You can compare any particular aspect of design or sound you want, but its just a small part or the total story.

Just saying. ITs fun to gab about such things I think.....

Sometimes, I feel like A Poor Misguided Fool.

Another musical interlude....

So hearing hiss is better than not hearing harmonics that can't be heard? I must be missing something?

Correct- you are missing something. The hiss which is the noise floor of a zero feedback circuit is at a low level, just as the noise floor of an amplifier with feedback is at a low level. The point is that the noise floor of a circuit with natural hiss will seem to have more detail, as our ears can hear information below then noise floor; in a circuit with feedback they can't.

Regarding your other comments re class D and tubes... you could get a tube amp to drive your speakers- you might want to use a set of ZEROs. Worth a try if you ever consider it. IMO Class D is a technology that may well prove to be superior. The answer is told by price/performance curves and the question is where is class D on its curve? If somewhere in the middle it may yet surpass existing technologies.

Since Transistors and Tubes are both mature technologies and Transistors being arrived at a lower performance level than Tubes, the fact is that our grandchildren will be arguing over the differences. But what this also means is that class D will overtake Transistors before it can overtake tubes. In some cases we have already seen this, so the theory is being proven in practice.

Put another way, will class D then overtake tubes?? That remains unknown at this time. What we *do* know is that it has not done so yet.

I maintain that you don't have to know anything about technology to understand that tubes are in fact superior. The simple fact is that at this time, tubes have been obsolete for longer than they were the only game in town! Think about that. Normally when a succeeding art appears, it supplants the prior art easily and there is not much looking back- the prior art becomes a cottage industry at best; cars and horse-drawn buggies are a good example.

But tubes are still vibrant- the market somehow continues to demand them half a century on after their declared 'obsolescence' (there are more manufacturers of tube gear in the US now than there was in 1958...). That's really all you need to know- if the succeeding art were really better, tubes would be long gone. You don't see them in TVs anymore and they've not been there for a long time. That says that tubes don't work as well as transistors in TVs- or computers! But they seem to do just fine in audio, and new types (KT150 being one of the latest) are being introduced. That's not a description of a technology that is obsolete.

Hi Mapman,
I have no doubt that the Bel Canto is a quite fine solution that fits your needs and I meant no criticism in any way. Ralph made certain points about the effects and consequences NFB that ring true in my listening endeavors and so it caught my attention. I of course agree with you in that there's inherent compromise with any amplifier choice. For what I seek and place the highest priority on, the simpler lower power amps minus the NFB get me the closest to that sound.
Charles,

My guess is Class D still has upside, but is pretty darn good already. I'm finding it better already than most Class A/B transistor amps. Class A/B/D all use transistors, right?

Tubes are not obsolete. They have unique charms. Definitely a small niche in the big picture though. Bigger in high end audio no doubt. That may not change.

High end audio will always have a special place for the other wise unconventional where it can exert some control in unique ways over the market.

The bigger question is does high end audio as it is comprised today grow or shrink over time as new innovations come about? Being stuck in the past is often not a good formula for growth.

Class D is a game changer IMHO. Tubes beware!

Charles,

I was looking at your system in conjunction with formulating my response.

No doubt, you have a well thought out setup with some very unique qualities as well and a lot of care has gone into it.

I have only gotten to the point in recent years where I am able to listen for hours on end given the opportunity and be continuously sucked further into the music.

I have a wife and kids, a house and jog and other hobbies as well, so you know how that goes. ALways something to do. All else aside, I can be quite happy just sitting and listening.

But there are so many ways to skin the cat. I hear great sounding stereos all the time now at shows, dealers, plus more good sound at live events when I get a chance. Tubes are often part of the equation, possibly a necessary ingredient still somewhere, just not in the power amp in my particular case.

The thing is there is so many ways to skin the cat and get good results. The common ingredient seems to be a love of music and a desire to get things just right in order to maximize the experience while it lasts. And maybe a tube or two or more can't hurt.

"The point is that the noise floor of a circuit with natural hiss will seem to have more detail, as our ears can hear information below then noise floor; in a circuit with feedback they can't"

Assuming the noise floor is low and can't be heard anyhow, what is there to hear below it?

Information! But just because you hear something over the noise doesn't mean you're hearing more. As often as not, probably less.

Hmmm, it seems a lot more practical to just do whatever you can to minimize noise. Even if you can' hear it explicitly, it typically affects sound quality in a negative way.

Again if I had to choose my noise, I would probably choose the more randomized, white noise, hissy type than any other type that might have more specific interactions with the actual signal. Maybe that's what Ralph is saying? Problem is I am just not hearing it. Ignorance is bliss I suppose. After all I may be just another poor misguided fool. :^(

I suppose I may have to turn in my audiophile credentials perhaps with the mindset that that which I do not hear can't hurt me. Fear of what we might be missing would seem to go with the turf.

Ralph, thanks for the explanation, which makes sense to me. Certainly, at least, to the extent of being a general tendency, that usually/more often than not differentiates tube and solid state designs.

I think that some of those who have responded may be losing sight of the fact that distortion does not occur when there is no signal to be distorted. In the case of a design that utilizes relatively large amounts of feedback, when Ralph refers to "the noise floor becoming that of harmonic and inharmonic low level distortions," that "noise floor" will not be heard when no signal is present, even if one's ear is placed against the speaker. Yet when signal is present, Ralph's point that it can mask low level detail to a greater degree than a small amount of hiss can mask low level detail (even if the hiss is great enough to be audible) certainly seems to me to be plausible.

Best regards,
-- Al

Al,
True and this is why Ralph's explanation struck a chord with me. The irony is that although tube amplifiers in some cases have more "audible" noise, once the music plays you hear 'more' musical nuance and low level information than with the 'quieter' amplifier. On the surface this seems counterintuitive yet it's the reality I've heard.
Charles,

Hi Mapman - if I may, Frogman's post of 10-22 explains quite well what professional musicians are missing when they listen to systems that do not have low level detail. It may be a very quiet system, but there is still information missing - some of the baby is being thrown out with the bath water. Most musicians would rather put up with some surface noise such as hiss but also be able to hear this low level detail - we work very hard at such things as Frogman is describing, and it is disappointing not to hear them reproduced. If you would like more explanation after re-reading, I'm sure he or I would be happy to try to elaborate some more.

Atmasphere, thanks very much indeed for your usual clarity of explanation. You have a gift for it; I have learned a great deal from you on this board - Al as well.

"In my experience, SS always seems to image more sharply and offer the deepest, clearest field. "

Apparently, not the case. Unless no negative feedback is used. At least not in some ways.

All we've heard so far is a generalization of 'large' amounts of NF. Nothing specific or specific for specific amps has been stated. There clearly remains a beneficial amount at which comparisons of tube and ss amps' performance level may converge. Hence the ongoing debate and differing preferences. There seems to be an awful lot of objective statements being made under the guise of subjective view points though.

Well, all that matters usually comes out in the end. You just have to trust your ears. There is no equation or theory that can account for that 100%.

My view is there are many aspects of design that matter. I've yet to determine that any single one is always the determining factor. Most things are a matter of degree,not black and white. Only ones ears can determine how it all adds up.

If this were not the case, then all the smart engineers in the world would more or less be designing things pretty much all the same way. But obviously they do not. I suppose that's part of what makes this stuff interesting.

Cutting tech hairs perhaps, but I'm wondering what is the distinction between noise and distortion?

Wouldn't the harmonic artifacts introduced by NF be considered a form of distortion rather than noise?

I think of "hiss" as a form of noise. I think of harmonic anomalies as a form of distortion.

Both are obviously unwanted, but maybe worth clarifying to avoid confusion in the interest of talking apples and apples.

I did find this dewscription of the difference between noise and distortion.

It would seem to infer that noise is a "random" artifact.

Artifacts resulting from NF would not seem to be random, so I am wondering if that qualifies as noise and can be considered as a factor in a discussion regarding noise floor?

Back on the "life is too short" topic, see This

Paul and Yoko now buddy buddys. "Life is very short...." indeed!

Assuming the noise floor is low and can't be heard anyhow, what is there to hear below it?

Al's comments above are the correct answer to this.

Chaos Theory points to the 'why' of it- the amplifier with feedback is operating in a chaotic fashion where the noise-distortion floor is much higher with a constantly changing non-repetitive signal.

Csontos makes a good point in his post above. IMO this has more to do with feedback and less to do with whether its tube or transistor in theory. In practice though it is much easier to build a zero feedback circuit using tubes than it is with transistors. Ninety-nine and 44/100% of all transistor amps run a considerable amount of feedback, hence the generalization.

For the time being designers have yet to universally recognize the importance of human hearing rules in audio design, so we are likely to see considerable differences in opinion for quite some time :)

In this conversation I've not discussed preamps although I have alluded to them by using the word 'circuit' as opposed to 'amplifier'. The same rules of human hearing of course apply to preamps, and you do deal with the same issues of feedback. However in preamps it is very easy to build a zero feedback circuit with vanishingly low distortion and wide bandwidth, so the argument in favor of feedback weakens considerably, especially in the face of the damage it can do (if you want to build the preamp with opamps though you are kind of stuck- that can only be done with feedback). If the preamp looses information, it really does not matter how good the amp or speakers are- you can't recover lost information downstream.

"For the time being designers have yet to universally recognize the importance of human hearing rules in audio design, so we are likely to see considerable differences in opinion for quite some time :) "

Few things are ever "universally" realized.

Does not make sense to me that such things would be ignored by the experts whose products can benefit.

More likely that different engineers make different judgements regarding what works best to meet specific product goals.

I'm a software engineer. Not much parallel I can think of where a long proven best practice is ignored these days by any good software engineer worth their salt.

Shigeki Yamamoto who is known for his line of SET amplifiers is very adamant about the adverse sonic repercussions of NFB. Even with his DAC design he eschewed OP- amps due to their copious levels of NFB and instead opted to build a discreet analog output circuit free of NFB same as his SET amplifiers. Another example of circuit and not limited to power amplifiers.

I'd like to hear from component designers/builders who believe in the advantages of NFB given its wide use and acceptance. I'm sure they feel ther are sonic benefits or they wouldn't use it. I wonder what's their opinion of the human hearing principle and if they accept the premise.
Charles,

I think the sonic benefits of NF is pretty well documented and understood as are the drawbacks (nothings perfect).

The fact that it is so widely applied would seem to speak for itself in terms of overall merit.

No NFB would seem to be the exception, not the rule. Those who buy into those benefits versus drawbacks have fewer options to choose from.

That's pretty much how these things work. Any product that is successful over time offers unique benefits.

One must also always keep in mind that there is a difference between theory and application. Theory is well, theoretical. Means nothing until realized in something in the real world you can touch , see, listen to, etc. That's what matters.

In my mind, the things that go into good sound are well documented and understood, especially by the "experts". Why re-hash here? Any assessment here is bound to be incomplete and flawed and affected by biases.

I've heard one of Ralph's amps at a show once with the big CAR speakers. It sounded very good. SO did other's at the show. Each had advantages/disadvantages beyond just sound quality. THings like cost, size, aesthetics, and other more subtle differences in features.

All that stuff matters. A lot of sound quality discussions are mostly about cutting hairs compared to the bigger things that the evidence clearly indicates matters to most.

Techno babbalo obfuscaturo a mundo. El tubo harmonico supremo.

"Techno babbalo obfuscaturo a mundo. El tubo harmonico supremo."

Eat Oreos. It'll all sound muy bien.

Few things are ever "universally" realized.

Does not make sense to me that such things would be ignored by the experts whose products can benefit.

Its all about the dollar. People often purchase audio gear with their eyes rather than their ears. Then once they are saddled with it they have to justify why so they can feel good about it. Its much easier to design with feedback than without. In the case of amplifiers, the use of feedback is common as it is part of a standard of how the speaker is driven. But the standard ignores human hearing/perceptual rules. I am sure many have seen this link before but here it is again:

http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php

In a nutshell the more your equipment obeys human hearing/perceptual rules the better it will sound, the involving it will be and the less likely that it will wind up in a closet or being resold. But if you are only interested in how good the equipment looks on paper you might think global NFB is a good thing.

"But if you are only interested in how good the equipment looks on paper you might think global NFB is a good thing. "

Its an old beaten topic, but actually I think most people, especially audiophiles, are more interested in how something sounds, not how it specs out on paper.

I suppose if its true we have all been brainwashed, or earwashed I suppose as it were (I could probably use on of those) we don't really know that most of our stuff does not sound as good as it might if we would just go with the gear that caters to our ears the best.

But having said that most afiles care more about the sound than the specs, if I hear something that sounds good but does not measure well ( to some reasonable reference standard that it probably should) a little question mark will likely go off in my head asking "why".

In general, technical standards are a good thing. Not sure why audio should be any different? That's one of the things that leaves high end audio open for criticism, lack of standards. In lieu of standards, its harder in general to decide what things will play well together. You have to rely more on specific more proprietary solutions designed to work well together. Proprietary usually means fewer choices. That can be a good or bad thing. How Apple does things is an example many can relate to. People who love their products rely on Apple exclusively to a huge degree. Its a closed product space where Apple alone makes the decisions and provides the options. Many like that! Many do not. I am NOT an Apple fan in general.

if I hear something that sounds good but does not measure well ( to some reasonable reference standard that it probably should) a little question mark will likely go off in my head asking "why".

Now you know why, the technical specs don't jive with human hearing/perceptual rules, which also answers the question below:

In general, technical standards are a good thing. Not sure why audio should be any different?

I am sure its possible to develop test/measurement techniques that *do* correlate with human hearing rules, but right now the industry has had no will to do so and has not for the last 45 years so don't hold your breath.

"I am sure its possible to develop test/measurement techniques that *do* correlate with human hearing rules, but right now the industry has had no will to do so and has not for the last 45 years so don't hold your breath."

I'm not.

I suppose the standards that are applied do correlate to some extent with human hearing rules. It would be hard to see how products could be sold if not.

But I suppose it can also be proposed there are better standards possible. Few standards are perfect, so I could see where this could be the case.

More a matter of degree, or Shades of Gray, like most things, as I see not, not black and white, right and wrong.

I submit that there isn't any rules for human hearing. It's clear that very few audiophiles can agree on a regular basis when it comes to which piece of gear sounds the best, or even better. It has been shown that people can even develop strong preference in A/B comparison where nothing actually changed. While I won't completely dismiss the idea that there's something to human hearing that's beyond scientific measurement, I don't believe that is any attribute of it that is consistent enough to be distinguished from placebo and personal preference.

Thank you to everyone that has commented on this thread.

Regarding solid state missing low level detail, does that then mean that tube amplifiers offer more subtle details which thereby produce a more complete amplification of the source material? I have been under the impression that tube amplifiers introduce distortion that is pleasant to the ears which is the hallmark of their signature sound. I am fully open to and happy to be wrong on this! I would like to know if tube amplifiers offer more information (more detail), less information (obscured by pleasant distortion), or simply different information (to each his own ie no technology is more accurate).

If solid-state amplification achieves its sharp details through the omission of low-level information, leaving a sharper contrast with the silent background, would this not be a plus for imaging as it allows sounds to be more readily located? Also, is this not an inherent quality of three dimensionality as the purpose of 3D is to stand out in relief to a background?

****would this not be a plus for imaging as it allows sounds to be more readily located? Also, is this not an inherent quality of three dimensionality as the purpose of 3D is to stand out in relief to a background?****

Yes, if one considers that to be a good thing even though it is accomplished at the expense of other things.

"Yes, if one considers that to be a good thing even though it is accomplished at the expense of other things. "

Frog, wondering what other things specifically?

Pinpoint imaging maybe?

I might agree with that but I tend to think of pinpoint imaging ability as a good omen, and maybe a good thing in some cases with recorded sound but not the end game.

Few listening scenarios in the real world are perceived in the absence of any surrounding acoustic context as a "pinpoint image" alone. More realistically there is a central focus and some spread around that.

Granted it is possible to set up lsitening and recording scenarios where each sound emitted is perceived as a "pinpoint" but that is just one scenario and a subset of all those possible.

I suppose this would boil down to the common question of whether reproduced sound does or should attempt to sound like a live performance. That one has been beat to death and I understand both perspectives.

I am in that says most things I hear I do not hear as pinpoint sources, so I do not want all my recordings to sound that way either. In some cases, that may be all there is to it, but that is the exception I think and not the rule.

I suppose the standards that are applied do correlate to some extent with human hearing rules. It would be hard to see how products could be sold if not.

What I am saying here in the last few posts is that for the most part, the measurement standards don't correlate all that well at all; about the only thing that gets much lip service is frequency response, based on the ear having response from about 20Hz-20KHz.

There is nothing in the measurements, for example, that acknowledges that the ear treats distortion as a tonality, other than 'low' distortion is supposed to be good. In practice though, it turns out that certain distortions must be very low, and others the ear does not seem to care about so much. There is no nuance in the specs!

I submit that there isn't[sic] any rules for human hearing. It's clear that very few audiophiles can agree on a regular basis when it comes to which piece of gear sounds the best, or even better.

You are confusing taste (for which there is no accounting) with actual perceptual rules, which vary over the entire population by about 1%. IOW there is a big difference here.

There are numerous examples, for example mp3s take advantage of the ear's masking rule (although not 100% successful in that regard) to reduce the amount of data storage.

"You are confusing taste (for which there is no accounting) with actual perceptual rules, which vary over the entire population by about 1%. IOW there is a big difference here."

Hmmm, not sure how far "rules" get you in lieu of "tastes" when it comes to people. I would expect one to reflect the other to some extent in general. Case by case, anything is possible.

I think another and more modern study might be called for. Technology has changed a lot over the years and peoples buying habits are the main driver. Maybe the rules get followed these days in more cases than one might thing otherwise.

I can only speak for my self. My system has NF applied and I am digging it! Then again, I am a bit of a rebel at heart. I might actually like breaking a rule or two now and then. :^)

Atmasphere, I suspect you are somewhat of a rebel at heart as well! I respect that!

All electronic components have a certain amount of noise associated with them that is additive through out the sytem. Look at the specifications of any device, solid state or tube and there are specs for the noise associated with that component. Therefore, signal or no signal, the circuit in questions will have some noise. Whether the gain in the circuit is there or not, there is noise, regardless of whether you can here it. It is measurable. The noise floor is there period. gain is added if gain devices are present and more noise is added if grounding is not good or ground loops are present. So, start off with a specific amount of noise (noise floor) of the device under test. It is there regardless. Connect this device to others and the other device's noise is also added. now you have system noise. For example. CD transport has noise A, DAC has noise B, Pre-amp has noise C, amplifiers have noise D. The total noise will be A+B+C+D. And if you have bad grounds or power line noise, then that adds also. Also, regardless of tube or solid state, a competent Engineer/Designer will design based on the noise, gain, input impedance, output impedance, load, etc. They pick electronic devices based on the load/gain characteristics and also based on the specified noise of the device. But, you get what you pay for. You want terrific gain/impedance devices? you want really low noise devices? you want devices that operate from DC to light? well, you will pay for it. This is also why some electronics costs soooo much.

enjoy

A rebel? Perhaps.
A businessman first and foremost.

Techno babbalo obfuscaturo amundo is definitely what's going on here. Because the question remains...is 'El tubo harmonico supremo? What are we talking about? NF vs. no NF, tubes vs. ss, or a whole host of variations in between? There's a lot of options here, never mind the degrees of implementation and where. There's also a lot of amps out there, the majority of which most or all of us have not auditioned or will ever. How much of an influence has the marketplace had on those we have indeed auditioned? I'm here taking up space and I'm telling everyone here that there are aspects of performance that trump the so-called obvious differences between tube and ss amps, rendering them absolutely moot. It just so happens that it's more difficult and takes more skill to design a good ss amp than it does to design a good tube amp. Hence the constant allusion to tubes by the ss market. The ratio is higher for tubes than for ss. I've heard bigger differences among ss amps than between tubes and ss. Ime tube amps sound more alike than do ss amps. That doesn't make them 'better'. It simply reveals a wider playing field within ss topologies.

El tubo even order harmonico bueno, solido stato odd order mundo problemico.

I've heard a lot of systems and a lot of combinations (pre and amp) of tubes w/ tubes, SS w/ tubes (both ways) and SS alone. In general I prefer "some" tubes in the system to SS alone, basically because tubes seem to add harmonic texture. Whether you call that distortion or not, well, I don't care. It sounds better to me.

SS alone does seem to be cleaner sounding, tighter, perhaps with more bass punch in general. All tubes seem to be very rich, but that doesn't have to mean sloppy.

IMO it is more important to match the amp with the speaker to get the best control, be that a tube amp or a SS amp. Then get a preamp that tunes the system more to your liking and both complements the amp and helps true up any deficiencies. We all know it's a synergy game and sometimes trial and error is necessary to get the best balance that works for your ears and musical tastes.

****A rebel? Perhaps.A businessman first and foremost.****

You know, I just don't get why some people feel the need to get one of their useless little barbs in. Here we have a guy (Ralph) with the knowledge and talent to bring something meaningful to the discussion, and who is willing to take the time to help those of us who are only capable of scratching the surface of a complicated subject, and instead of showing some appreciation, cynicism has to be thrown in. I have no relation to Atmasphere and don't own any of their products, but I am grateful for his contributions to these dicussions. His comments make a lot of sense to me. Obviously, we dont always have to agree with any one person's viewpoint; but, when a guy is capable of designing equipment which consistently gets great reviews and commentary that focuses on how all of the "mumbo jumbo" actually relates to MUSIC and things other than the usual lame numbers game, I for one, am going to listen. If I misconstrued the comment, my apology. OK, I feel better now.

+1 Frogman.
Another observation with cynical replies like Wc65 mustang's, there's hardly any meaningful followup or contribution . Just an opportunity to get in a smarmy remark that's supposedly witty (but isn't). If there's more to say, lets hear it. I don't always agree with Ralph (or anyone) but I certainly respect his knowledge and contributions.
Charles,

It's not always clear on this site who is in "the business" or not, so I have no problems with that being pointed out.

In the case of Atmasphere, it would be silly to question his credentials, and he obviously knows what he is doing.

He is in "the business" though nonetheless and selling products as are many others here so that is always worth knowing along with all the other good information that he and others share for free here. It all just goes with the turf I would say. Comments/opinions should not be censored. Anyone should be free to disagree with anyone at anytime. I would say though that it should also be done in a civilized and respectful manner though. A sense of humor doesn't hurt either. Home audio is not life or death, just fun, business, whatever. Everyone just play nice and we should all be fine.

At least that's how I look at it...

We all have objective viewpoints we're not revealing here. If we struck the word 'is' from the English language and from our memories, we'd have to revive Latin as our universal language. Imagine the length of the posts:)