Are future improvements in Amp/PreAmps slowing to a crawl?


don_c55
OK- so despite my asking several times it appears you did have a measurement system after all! Why didn't you just come out and say so the first time I asked?

Air is anything but a constant when dealing with the speed of sound. Humidity and air pressure both play a role. Do you have compensation for pressure and humidity?

I'm having a problem with several other comments here as well. One was the speed of the power supply and another was the speed of the amplifier. Long ago I discovered that any power supply has a timing constant and if the amplifier goes lower than that constant IM distortion will rise. So that is a rule I've been careful to follow. But from your comments it sounds as if you are talking about something else. 

Also the speed of the amp is another area that is well understood. Are you referring to the speed of the amplifier as propagation delay? 

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Here are some comments...

http://v2.stereotimes.com/post/hcat-df100-mk-iv-and-high-fidelity-pro-cables-a-followup/

This was coupled with another product under review at the same time.
It also preceded the most recent breakthrough (higher rez) that is yet to be reviewed.
I don't understand much, if any, of Mr. Paul's explanations for his discovery/invention
I would not feel bad about that. I suspect that mach 1 has nothing to do with the inside of an amp. Given two explanations, its likely that the simpler one is the correct explanation. We have Mr. Paul's rather lengthy explanations and we also have a very simple explanation for the same thing.
Air is anything but a constant when dealing with the speed of sound. Humidity and air pressure both play a role. Do you have compensation for pressure and humidity?

There is no compensation necessary. Assume 750 mph as normal. Even if the concert hall all of a suddenly became 20 degrees warmer and loaded with humidity the actual speed of sound may go up or down by a small percentage but where ever it ends up - (751 mph?) it is constant.

For it to have an impact on the velocity tracking that I'm talking about it would have to change (as above) between notes in the performance.
And even then it could only screw up the image for that quick second until it remains stable again at the new value. Temp and humidity generally take a long slow time to modify the speed of sound.

OK- so despite my asking several times it appears you did have a measurement system after all! Why didn't you just come out and say so the first time I asked?
This measurement is something that is applied to the circuit design itself - not to the unit on the bench. It tells me the level of resolution that the built unit will have. But it is not something that you can attach as probes to the hardware itself. Once I have the data given by the virtual analyzer it only confirms the current circuit configuration and settings will be repeated for each unit built to that schematic. 

If I were to try modifying the circuit to increase the resolution - it would have to pass the virtual test measurement first before implementing the mod into production.

I designed the computer model to interact with some of the hooks in the spice simulation software. I also use the Tina software (Texas Instruments) simulator.

I actually had to contact TI and notify them of a bug I found in the software that was falsely reporting raw THD measurements. They have since recognized the problem and have updated their software.

Their technical staff suggested I "send them my schematic" and they will see what kind of distortion issues I have. (Ha!) I said no thanks just fix the program.

Hm. I don't suppose you see where the problems are in your response here?

I'll point them out: First, apparently you don't have a measurement system as one of your recent posts seemed to suggest. You have a simulation method. Simulations are great when the simulation system works and they really suck when they don't. The thing is, if you don't then back up the sims with actual real world data, the sim might be helpful but you can't know that its accurate. Some simulators are pretty good these days, but I've seen them be a mile off.

One example I know of resulted in an ESL to be really hard to drive. Turned out the sim was nothing like the real world measurement- it was a country mile off. Once that was pointed out to the designer and corrected, the speaker became a whole lot easier to drive and better sounding at the same time.

In your case we have several problems. First, there is nothing to suggest that an amplifier has to operate at the speed of sound. I think any designer would agree that a good amp will treat all frequencies with the same speed. Most are much faster but none run at the speed of light. So you have to make a far more convincing argument; one that is backed up by some sort of physical law. The conclusion you jump to by simply declaring that amps have to be as slow as air is not logical- but I can see it appealing to those who don't have an engineering background.

The second problem is a physical measurement of the performance of your circuit is required. Without it no-one (including you) could say if it even works at all- right now the position you seem to be in is that you have an amplifier that sounds nice but to separate it from the competition you've come up with a panacea that no-one in the industry seems to have even heard of!

The problem with that scenario is that sooner or later you will run into someone that takes it personally when they see that there is an attempt to pull the wool over their eyes. Further telling them that they are just not up to 'speed' (if you will pardon the expression) is not actually the way to solve that problem; in fact its a recipe for making it worse.

What's hurting you right now is you don't have any means of proving that what you say is true. Its not enough to ask someone to trust you. Its further not enough to say that you've been working on it for however many decades (or that you found a bug with someone else's product; I can tell you from personal experience no-one cares). People often devote their lives to ideas that are mistaken. So I would encourage you to come up with a physical test that allows you to differentiate your amplifiers in the way that you say they are different.  Put it in a box and then show how other amps to measure up.
What’s hurting you right now is you don’t have any means of proving that what you say is true

I’m not being hurt by this. its just like the quote says "A Failure to Communicate"

The concept of two speeds referenced in an amp is just not registering.
Until there is a way I can tell this in a way the an "EE" can understand it - its not going to happen.

There are 2 axis seen in o’scopes
A sound event has data that is displayed on both axis.

1: The event has height or amplitude (you see a transit that might represent a rim shot)

2: It has a time or duration (see on a scope as the horizontal distance from when the transient started to when the transient ends.

If you want to know how long it lasted you would adjust the horizontal sweep rate to "spread out the display so as to get an accurate time or duration of this event.

Hopefully there is no disagreement with this statement..

Take the slew rate for example. It is defined as volts per microsecond.
Volts = height or vertical distance traveled
Microsecond = Time it took to swing that many volts from beginning to end.

I don’t want to confuse you by talking about slew rate - I just want to separate the vertical axis (and what it represents) from the horizontal axis (and what it represents)

When audiophiles remark that "wow this is a fast amp" they are generally talking about the ability of the amp to put out quick transients (tiny bells, upper keys on a piano, triangles etc.)
Clearly they are talking about it being faster than perhaps another amp that can’t "present" the top end as well. The latter may have a worse slew rate or some bandwidth limitation that does not allow the extension of the upper part of the spectrum.

You were closer to understanding what I’m talking about when you refereed to propagation delay or group delay.

If I said that the INPUT signal (source) has a speed (before it even begins to travel through the amp) would that make sense to you?

I believe a have a way to describe this with more clarity.

Let me use a different word to describe it.

What if I said my amp circuits have constant gain?
Did you know that you can vary the pitch by varying the gain?
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You were closer to understanding what I’m talking about when you refereed to propagation delay or group delay.
I did ask you about that earlier but you seemed to not respond. So is propagation delay what you are talking about? IOW, if the amp has constant propagation delay over the entire band of frequencies to be amplified, would that satisfy what you are looking for?
I agree 100%
I do not have a single device with perfect linearity because it does not (currently) exist.

The harmonics arise from unavoidable variations in gain.

Thank you - this makes my point that you can alter the pitch by varying the gain.The harmonics are the result of sliding the fundamental to a different area of the spectrum.

A change in gain is a change in velocity.
When you stabilize the velocity - you stabilize the gain.
A stable (constant) gain is linear.
A linear amplifier has no distortion.

What I have is a circuit that is 100% linear. (made from non-linear devices).

All that is needed is to use the devices in such a way as to force the output to be linear on a scale that is inconceivable.

A word about my previous comments...
I want to walk back my statements about the text books.
before you get too excited its not for the reason you think.

I’m sure that everything I have done can be found in the text books as individual or separate phenomena. What is not in the books is the composite use of various phenomena to produce a result for which there is no reference or example.

I have developed a way to take advantage of known phenomena involving aspects of how sound waves flow in air and created a circuit that treats the (sound wave) data as if it was in the acoustic environment.

This successfully "feeds" the brain in such a way as to believe these sounds are real (live) and happening in your airspace.


Question: why be so concerned about distortion of the amplifier? Didn't we find out a long time ago that some amplifiers with relatively high THD - I.e., more than an order of magnitude higher than those amps with vanishing low THD - actually sounded considerably better? 

Didn't we find out a long time ago that some amplifiers with relatively high THD - I.e., more than an order of magnitude higher than those amps with vanishing low THD - actually sounded considerably better?
Quite often, yes. The ear does not seem to care so much about lower ordered harmonics, but cares a lot about higher ordered harmonics (5th and above) as well as IMD and inharmonic distortions such as aliasing.

The latter three can be in trace amounts that are hard to measure but are easily heard by the ear (which converts them to tonality) as brightness and harshness.

Its not that hard to design an amplifier that is absent the higher ordered harmonics. Such an amp will not use any loop feedback though, as feedback will add harmonic content and IMD of its own regardless of the left/right 'speed' of the amp (as seen on an oscilloscope). See Norman Crowhurst.

SETs have been taking advantage of this for some time now (part of the reason they have such an avid following in high end audio). We do as well, but get rid of considerably more distortion merely by using fully differential balanced topology and only one stage of gain.
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^^ That is correct.

The ideal for amp and loudspeaker interface has been the idea of the voltage paradigm or voltage rules, wherein the speaker is 'voltage driven' and the amp behaves as a 'voltage source' which means it can make constant voltage regardless of load.

But SETs and a good number of other amps (including ours) do not work on those rules. Fortunately there are a good number of loudspeaker manufacturers that prefer the sound of tubes, and so make speakers that do not require that the amp be a perfect voltage source- far from it, in some cases.

The idea behind the voltage rules is plug and play flat frequency response with no adjustment needed to the amp or speaker. However no speaker is entirely flat and it turns out that the human ear/brain system has tipping points where tonality created by distortion is favored over actual frequency response errors. So the benefit of having perfectly flat response is reduced in the face of the fact that to get it, many amps have to employ loop negative feedback. Such use is known to add harmonic and IM distortions of its own, so many designers choose to use no feedback at all. This means that you have to be a bit more careful about speaker choice, but the result is more musical and more neutral.

This has been going on in high end audio for decades. So the result is that you simply have to be careful to match the amp and speakers together. Its my opinion that you go with the amp first and the speaker second, because the first problem to solve is whether you prefer tubes or transistors. People that prefer tubes usually don't like it when things are bright, so if you already got the speaker first you may wind up flushing a lot of money down the loo without satisfaction.



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Progress will be when a "full function" preamp has useful tone controls once again... 
Kosst
 
The problem I've got with the concept of "perfect" or "zero distortion" amps is that it really doesn't matter. How perfect is that amp with a loudspeaker drawing current all out of phase, pumping power back into the amp, and presenting impedances all over the chart? Is it still putting out that perfect signal?

Golly if I had known this I could have given up years ago and saved myself a lot of work.

Its not that hard to design an amplifier that is absent the higher ordered harmonics. Such an amp will not use any loop feedback though, as feedback will add harmonic content and IMD of its own regardless of the left/right ’speed’ of the amp (as seen on an oscilloscope). See Norman Crowhurst.
Actually, I fixed that.

I have not yet published it, as I’m waiting to be able to produce an amplifier and sell it to people, before others grab it away and make it their own -to do their shtick of stealing other’s ideas and thunder. I showed it to a ~very~ well known amp designer and explained why/how it works, and he called it, and I quote: "f**king brilliant". I don’t design circuits, per se, but I do understand the overall complex physics in-situ, more than some might.
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kosst_amojan,

If designers are discouraged in making improvements or trying to "perfect" a component because another component has its own issues then there would be no progress made anywhere.

Since I have succeeded in cleaning up distortion in amplifiers I guess I'll have to address the speaker issues next. However it might surprise many readers here that the bulk of ALL issues in a given playback system are in fact tied to the electronics. If you had the perfect amplifying method - a pair of Radio Shack book shelf speakers would still give you incredible imaging.

Its the electronics that provides 90% of a systems quality.
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+1 This is just blatant nonsense. On the other hand, it mirrors and feeds on  the obsession of many audiophiles with exotic electronics. These days, the electronics are  boringly irrelevant once you reach a decent quality level (and that level is easily achieved and cheap).
It's the electronics that provides 10% of a system's quality... which can be critical to certain aspect of the listening experience, once xlnt speakers are used.
Sure, you need to have enough power (and for top level speakers lots of power), and the frequency response has to load independent (within 0.2 dB for your speakers). Both require a beefy (and hence more expensive) power supply. Even so, this can be achieved at relatively modest cost if you avoid boutique brands. Look here for an example: http://www.homecinema-fr.com/forum/amplificateurs-de-puissance-haute-fidelite/mesures-ampli-yamaha-p3500s-mise-a-jour-t30056383.html
Sorry boys your wrong. This is what you believe because you have no reference when it comes to hearing what a distortion free amplifier can do.

I have the evidence of what I speak. I realize it might be hard to imagine that such a breakthrough in sound reproduction can come along but its here.

I have actually cloned the original sound event (concert hall) and I can drop that air pattern into your living room. So help me God.

Stay tuned to the news.
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Don't you think that after working on this method for 30 years that it might be something that you would at least give the benefit of the doubt to?

Its not like you went to see for yourself what this could be even if you think it is a hoax or BS. Your looking at this from the wrong end of the telescope. I'm not saying "I think" I can make a cloned copy of an event. I have the working technology already up and running.

You guys seem like a plethora of naysayers and Debbie downers.
Your wasting energy trying to tell me that I cannot do what I just did.
I'm not looking for any special praise or kudos - just to be heard and taken seriously.

The correct answer is "wow this sounds interesting but I would like to hear that for myself"
Instead "Your sounding like a crack pot or nutty professor or delusional"
"You can't do that because...bla bla bla."
"Face it we all live with some degree of distortion in the system"
And then you list 10 things that prevent me from succeeding.
All of which I have overcome.

Every attempt at "3D" without exception has involved some type of parlor trick or "enhancement" circuitry to give the listener the illusion of "surround" sound. 

Zero distortion is 3D.

I'm officially blue in the face so I think this will be my last post.
I want to thank the "other" readers of this thread that did not jump in with reasons I'm going to fail.

Seriously - good luck to those that enjoy the pleasure of listening to music without the hassle of politics or prejudices brought on by brand loyalty or designer gurus.  

Even Fox News thought this was a hoax (at first).

See you in the future.

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I usually tell people that the room is 50% of the system. There's not a lot you can do with the very best system if the room sucks. Conversely a very modest system can do great things in a good room.

If you had the perfect amplifying method - a pair of Radio Shack book shelf speakers would still give you incredible imaging.
I used to work at the Allied Radio service center in Minnesota. Radio Shack speakers imaged just fine if they were set up right, even with one of their lowly receivers like the STA-76. If you put better gear on them they did even better. One of their speakers used the Lineaum tweeter; Tandy bought out Lineaum just to get the technology for a $250.00 pair of speakers. They got good reviews in TAS on that model FWIW.
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I still have a pair of Radio Shack Optimus Pro LX5, which has the Lineaum tweeter. While it's no ESL, the tweeter is way better than a lot of domes.
Humidity, air temperature and air pressure should not be a SQ problem for anything the size of a living room or smaller.

In the early days of jazz, some bands (or house parties) are said to have been heard 1.5 to 3 miles away, and some say it was partly due to the high humidity in the NoLa air.
" I have seen the future, I can't afford it"

not really

i suspect Ralph is right
There are plenty of frontiers to be pushed back

i do have much much respect for Nelson and he is a deep thinker and a doer - you don't always see those together.. my first real high end amp was his 400, probably should have kept it...

the pount about what people hear hear and how is critical, iMO critical to moving forward in a science based way vs opinion on flavors...

for example 30 years of work at Vandersteen on the importance of preserving time and phase and now MQA and the recognition of spatial blur and human sensitivity to blur vs the IMO previous holy grail of flat response.

a systems thinker might say MQA is no advance if you feed a cleaned up temporal signal into an amp with high levels of negative FB

so IMO expanding the frontier is more about alignment of design philosophy across the system vs just box obsession...

putting my $ where my ears are
ordered Vandersteen amps

some innovations:

built in power conditioning
built in HRS isolation
no digital chips in the analog control circuits
unique topology with 5 parts in signal Paton emitervresisters
liquid cooled
list goes on
and on

so yes innovation alive and well
and frankly IMO a very exciting time in Audio

I said it before on this thread and I very much feel this is where the big improvements will be made:

One area that is a problem for all amplifier designs is that most are designed to have specs that look good on paper and are not really designed to also sound good. Now this is a simple engineering problem (understanding the rules of human hearing and designing to those standards rather than the existing set of arbitrary rules); the bigger problem is tradition- the tradition of how we say what are good measurements and what are not is at the heart of the issue. How do you get the industry to move off of standards set in place 60 years ago??

Until we fix *that* problem, progress will only be had by the outliers who are willing to buck the tradition and pay the price. And they are out there.
IOW its simple engineering, but if we apply our engineering to making equipment that looks good on paper, but at the same time does not acknowledge how the human ear/brain system perceives sound, then we won't make any progress.  We have to overcome the traditions of decades to do that- most of the specs we revere on paper were developed in the 1960s and a lot has been learned about human physiology since then!
ok, now I'm curious - where can I read about the advances in understanding human hearing & perception (psych. not physiol.) thereof since the 1960s?
I even listed the signal and measurement requirements for a given measurement and its analysis to be comparable to what human hearing says the signal sounds like.

I did this in some posts, a few years back, in the blowtorch thread over at DIYAudio.

There were enough audio engineers in that thread that someone should have paid attention. I outlined the signal type, it's measurement or measurement weighting... and how this correlated to human hearing.

Not one word said in objection, utter silence. But that might have been a good thing, maybe some of them were listening. Then this equation: Proper question = proper answer.

On of the answers is that you can't get back the signal you pt in, each and very single part and wire that deals with signal is distortion/noise additive or obscuring in nature, an all done slower than the original delta in simplicity an complexity of signal. We are always in a reduced situation.

Which is why false detail swamped in distortions is the norm, which is why some have such trouble in discernment. And spending money in incorrect ways to try and pull out information that is not actually there. All we can do is make a slightly less rich and slightly darker copy of the original signal, nothing more. A chain of components and cables that makes things seem more open is exactly that, 'makes things seem'.

People don't want to hear the truth of the matter, they just want to noise shape their way into perceiving more detail.

Then play the game of shaping that noise and taming it, one cable or component chained with the next. fighting their way through balancing out slow dark fog and hyper etched screech. and the more you chain together the more it comes out as "thumpy screech". The end game of a system package acting as a loudness button slash transient modifier, all chock full of metallic originated noise. It can get very very bad in some systems. So bad I can't stand being in the same room.

Some audiophiles have become so connected to such gear and such intent, that you can't explain to them that they've pooched the idea of real dynamics without noise so badly ... that their $10-20-50-100k systems are a complete waste of time. so unmusical that it is actually painful to hear.
I hate to judge these things too quickly but it certainly appears that human sensory perception, psychoacoustics and how the brain interacts with its surroundings (mind matter interaction) are subjects that tend to make grown men and audiophiles run in the opposite direction as fast as their little feet will carry them. What grown men really want is far from neuroscience or evolution, very far. What they really want is things that make sense. Not things that go bump in the night. Something they can vaguely remember from high school or find quickly on Wikipedia. Something that at least looks like real science, real engineering. Something they can measure. Well, not them, specifically, but somebody. 😬

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ok, now I’m curious - where can I read about the advances in understanding human hearing & perception thereof (psych. not physiol.) since the 1960s?

beyond any Google or Gloggle?

if you have a book or review paper post the cite & I will check it out

I have access to Jstor and other scientific and engineering sources
@raindance 

You said "Progress will be when a "full function" preamp has useful tone controls once again..." -Wholeheartedly agreed; let's get some full function back. You may not have to use them most of the time, but they are sure a lifesaver when needed.
I’d say about 90% of the problem audiophiles face is getting all the music that is in the grooves and all the data that is on the disc. It’s really a playback problem. The challenge is to resurrect or archaeologically dig up the information, clean it, deinterleaved it, make it coherent, so it makes sense. You are not protected by the Error Detection/Correction algorithms. Only 10% has to do with equipment and even cables.

Without tweaks, without isolation, without room treatments, there can be no high end. There is no artificial ceiling that cannot be broken through, some silly line that signifies Audio Nirvana. There is no hyperbolic curve of system performance. Hel-loo! Those who believe they only have 2% or 5% left to go before they reach Audio Nirvana are simply mistaken. You don’t know what you don’t know. 😳 Think of Audio Nirvana like climbers climbing Mount Everest. Many climbers get up one morning and declare, "Hey, we made it! What a view!" 🏔 Then they’re informed, "Dude, chill! We’re only at Base Camp." Which by the way is only half way up Everest. 😛

ok, now I’m curious - where can I read about the advances in understanding human hearing & perception thereof (psych. not physiol.) since the 1960s?
You gotta pound the heck out of google. Here's a fun one:

https://pdfs.semanticscholar.org/2f03/7a2adec2af5953b4f84ca6b2e2b3f30a3bf3.pdf

And its the tip of the iceberg. Note how the limbic system is involved...  more:

https://pdfs.semanticscholar.org/2f03/7a2adec2af5953b4f84ca6b2e2b3f30a3bf3.pdf

GE did a study back in the 1960s that showed that the brain uses higher ordered harmonics to gauge sound pressure, but the study does not appear to be online. However this particular fact is easy to prove with very basic test equipment. Oddly though, the implications of just this fact are largely ignored by the audio industry.

Going even further back, we've known since the 1930s that certain harmonics have certain audible effects, for example the 7th can impart a metallic quality (and in small amounts; see the Radiotron Designer's Handbook) but this fact again is largely ignored.
Which is why I chase after the removal of all metals that have hysteresis issues, when involved in an audio signal. This delayed response tends to contribute to the harmonic structure of the end signal, smearing it across time and then being heard as 'loud' when it is merely obscuring metallic sounding distortions which are stretched in time.

audiophiles are so inured to this sonic aspect that they many times don't recognize a truly correctly delivered set of intermixed transients.

Or they do recognize the noise and employ gear or cables that swamp it with damping distortions, and dull the irritating aspects out. Then the next piece in the line of gear distorts and exacerbates the transient noise problem again and then the next cable or speaker or whatnot, blunts them.

They end up with a system that is built out of 'dulled screech' and then wonder why they keep changing gear out, over and over and over and getting to exactly zero fidelity.

There is no magic single bullet in any given system, there is only all pieces individually doing their best to not damage the signal--but more importantly, not add to it.

Yet we are wired to seek out this micro detail, due to our biological function.

It' a complex affair that requires some notable mental wrangling and retraining of hearing function.

Most people won't work on themselves, they project, as that is what ego does. With music we do so very much engage the wiring of survival and bodily procreation (music hits the same area of the brain as sex), thus we engage the blind side of the ego and it's projection.

Thus the audio arguments and intractable positions and the unending battle to have one's projection be the real one for all (ego demands that the world reflect). This is stuff is taken personally, all affront, all the time. Our balls are on the line. Literally. At least as far and mind and body are concerned.

Underneath this gigantic projected mess of an audio world, there is some basic truth but it tends to be the path less traveled. The best gear is known by less and less people while mediocrity has the lion's share of the sales. This is true in any commercial endeavor that has a large cross section of humanity's possible characters involved in it.