Roger believed in his product enough to let you hear it for yourself. To test the device in question. IOW, he put up. You, on the other hand, irrespective of the circumstances, HAVE NOT put up. It is that simple. Everything else is chest thumping. I have in no way said that I believe what he has said. If you could please point out where I said that, I would be grateful. On the other hand, I have not discounted it either. I am curious though, what exactly would you "risk" by listening to this piece of equipment? Your pride? Your beliefs? Financial obligation aside of course. I would love to audition one of these. Of course, IF (note I said if) I found it to do what Roger says and reported it as I heard it, I would be labeled a kool aid drinker, a dupe, and subject to confirmation bias because it cannot possibly be so. It would be better if one of the people that claims this to be snake oil actually test it in their own system and report what they heard. If you heard Roger's device do what he describes, would you be man enough to come back to these pages and report that?
The point of this thread was to discuss Nelson’s statement that amps are a solved problem, that there is no technically perfect amp, and that they are, for all intents and purposes, art.
I understand that it is his viewpoint or opinion but it is not factual. His mission or target or goal (according to the article) is to make an amp with a particular "sound" or signature.
Pass:
There are few things I enjoy so much as to contemplate the specific (and complex) characteristics of the many transistors (or tubes) and how they might fit into an amplifier to deliver a sound which has a particular signature.
Rather than go through all the devices as if they were shades of paint on a mixing palette - I prefer to make an amp with "no sound". By default in order to have a "sound" the amplifier modifies the pure input signal to include a form of distortion or corruption based on the devices used. It is not necessarily bad thing but I don't want to hear the parts - the only thing I want to hear is the music.
As far as bold statements - I am trying to be polite. I have a policy of not criticizing or speaking ill of other designers. Mr. Pass by his own words is not seeking the perfect amp. I am.
I could give you a few bold statements of fact but it generally won't sit well with some individuals that post or read this thread. It would be good news for some and bad news for others.
I think the engineering science to design and produce a straight wire with gain reached sonic perfection in the 1980's. The next advance was in improved manufacturing technology that made such amplifiers considerably cheaper (unless you wanted the mystique of audiophile stuff that ironically was often far worse). Right now, and I suspect even more so in the future, the technological drive will come from the need to be more energy efficient. In Europe, mandatory standards of energy efficiency are tightened for more and more products. For example, our recent vacuum cleaner that comforms to new EU standards uses only half of what the previous premium model did, and is far quieter and lighter to carry (and it sucks dirt rather better). The same is happening everywhere, and the only reason that e.g. class A amplifiers have not yet been outlawed is that there are probably too few of them around. But new TVs have to meet pretty stringent legislation. I suspect this is a large part of what is driving class D developement.
I think the engineering science to design and produce a straight wire with gain reached sonic perfection in the 1980's.
I would agree with this except I would say it reached its sonic "limits" in the 1980's. It never reached perfection. The need to be energy efficient is a noble cause as well however I think that removing distortion found its limit when it was clear that lower THD measurements, while impressive to those buying by specs only, proved to be seemingly unrelated to the actual sound of a system. Tube gear (with admittedly higher THD) still dominated the high end market. Even today the tube gear still enjoys a comfortable percentage of the high end market. Many SS designers would be happy if they can get their gear to sound like tubes.
One of the biggest surprises I've run into is how much information is actually captured in the recordings. The resolution of the image embedded in the source is vastly superior to what was assumed as a limitation. The real problem seems to be with the resolution of the playback system.
If you recall I was offering to send you a preamp - not an amp.The entire playback chain is the amplifying process. The core process I have developed is zero distortion. This circuitry is an analog "block" that you use to make a phono stage, a DAC (output stage), a line stage and the voltage gain stage in the power amp. The output section passes the phase coherent signal to the loudspeakers. There will be limitations when driving speakers that do not adhere to the same coherency do to its design. Obviously you must have at least decent speakers.
Perfect mediums? Which perfect medium exactly?
If you are asking about the medium of air - there is no distortion presented to the sound waves traveling through air. The two times you use air as a conduit starting at the original venue is the air space in studio or hall and the air space in your listening room. These two segments have no distortion. The electronics between those segments has to approach the same level of purity found in air.
For example just by switching the preamp in an existing system of otherwise decent electronics can give you many more magnitudes of resolution and information compared to a conventional preamp. The same holds true for the phono stage. Without replacing your power amp.
I'm sorry for the confusion but when I talk about amplification I am not always referring to a power amp.There are enough problems before you get to the power amp that already restricts what you can expect to be passed on to the speakers.
what perfect gain devices are you using in your perfect circuits?
Here you are talking about two different things. It is possible to have a perfect circuit without perfect gain devices as long as the result of a unique configuration produces the perfect output. I also manufacture my own devices used in critical areas of the circuit because they don't make a device capable of behaving the way that is required to cause the overall circuit to have a linear output. My target was to detect velocity in the source signal and force the output to be synchronized to the recovered velocity which is clearly embedded in the recording. This gives you a way to match the playback speed with the recorded speed. If you don't do this you end up with an unstable or smeared image. This "out of focus" nature of such an image hides the extremely fine details missing in playback. The more stability - the more resolution. This can be seen by simply reducing mechanical vibrations in the system as well as better overall grounding which also helps to stabilize the image.
What is perfect gain?
Perfect gain is gain that does not change under load. Again I'm not talking specifically about a power amp. The desired holographic image will collapse do to any non linear segment in the entire chain. Perfect gain in the analog world is a fixed numeric value that is used to amplify the input signal at any point in the 360 deg range. If you take a line stage that has 6db of gain or an amplification factor of 2.0 then of course to be linear it would need to stay at 2.0 during the entire dynamic range.
If as the signal approaches the first positive peak and it falls short by a tiny amount (like the amplification factor at that moment was 1.998) then this is a sign that the amplifier has literally slowed down and the signal has a degree of compression that makes the shape of the current signal (fragment) look like a lower frequency. The same holds true for any segment in the 360 degree signal that somehow ended up with a gain of 2.002 - in this case the speed of the amp has gone up. The expected value of the peak has been passed and is seen as an acceleration in velocity. This non linear nature is what causes the playback speed to vary. Harmonic distortion is the direct result of accelerating the fundamental frequency to a higher part of the spectrum.
By detecting the velocity rather than trying to make a crude "comparison" as in classic feedback attempts - you simply hold the velocity constant. Constant velocity is constant gain. Constant gain is linear. Under these circumstances, there is no way for it to cause the speed to vary and as a result it does not have the ability to generate harmonic distortion. Holding the velocity constant is done as a phase correction. The greater the ability to detect velocity gives you better ability to hold it constant. This type of correction is done along the horizontal or time domain axis - not in the vertical axis the way classic feedback works. It also does it in real time preventing any form of distortion from appearing at the output of the circuit. This is what makes this method of amplifying distortion-less.
Detecting velocity is extremely difficult and requires sensitivity of astronomical proportion. This is what took me years to figure out. This high gain detector drives the automatic focus system
Advances in the velocity detector over the years has given rise to resolution as seen by the version nomenclature like the X-8, X-9, and so on. It currently stands at X-12 and is the final version because at this level of correction - the detector now gives 100% control to the auto-focus system. No additional correction is necessary.
The detector can discern changes in velocity as small as a few micro-degrees. As a result the output of the circuit can be totally phase locked to the fundamental (input) signal. As long as the lock holds - it produces a clone of the input signal. The lock is good down to (and below) the noise floor. When no signal is present the auto-focus can maintain a lock on the actual Johnson or shot noise seen at the noise floor. Any music signal rising up from the noise floor is already totally locked. This means that the auto-focus can accurately project tiny sound objects in the background at tremendous depths while providing massive detail for anything in the sound stage at any distance. It does this with 100% transparency starting from a jet black background. Percussion instruments are startling and because the brain is use to listening to live music coming through air - it readily accepts sound waves with similar stability as live.
The average person listening to a full system that works this way for the first time can't make it passed the first 10 seconds without looking around and saying "what the hell is this?" they cannot wrap their head around what is taking place because it seems both impossible and live.
Although a conventional system can sound spectacular - after listening to a system that does not distort - and returning back to the conventional system - it now sounds distorted.
Here is a simple test for distortion: Can you tell if your listening to tubes or solid state? Do you recognize a 12ax7 or a mosfet? Does it have a "signature" sound?
If you can recognize any device used anywhere in the system - its distorted. It is leaving a finger print of that device on the music signal. You cannot hear H-CAT. It has no sound. By re-enacting the disturbance pattern of the original air space in your own listening room you have cloned the sound event. The result is pure music with instruments suspended in mid-air as a ghost like image.
Early on in the project (years) you can see the THD drop to low levels by making a specific part of the circuit take over the handling of the input signal. Once the distortion hits the noise floor - two possibilities exist. If the noise is seen on a spectrum analyzer is -100db then the distortion is either -100 as well (or less). Listening tests at that point reveal a caliber of resolution that can be associated with those numbers. After that point any further improvements (hearing more resolution/less distortion) is happening below -100db. If you monitor it over time you can see the random nature of the noise will occasionally drop below -100 for a brief time. When this happens it exposes the harmonic measurement which if it was -100 then even in the absence of noise it would still read -100. Instead it measures -130db. This quick peak indicates that the distortion is still being driven to deeper levels and you can verify by what you hear that you are going in the right direction. After that point the THD analyzer is of no use. Now we take over with the math to determine how far down it wold be. Because of the phase lock kicking in and stopping it from being able to generate harmonics - you now can use the degree of resolution as a gauge going forward. As I continue to raise the sensitivity of the detector by X amount - it translates directly into an increase in resolution. It is obvious when resolution goes up - other instruments that you never heard before are now "visible". Again, continuing to raise the detector output gives you the numbers needed to calculate the degree of lock presented to the fundamental. At this point it no longer can distort at least as seen by harmonic output. Now we are down to how much bandwidth are we limiting the fundamental to vary. As the detector continued to improve I can calculate how much phase shift is now allowable as far as deviation from the fundamental frequency. Since I know that the detector sensitivity can be triggered by as little as a few micro-degrees, It ensures that the smaller the allowable phase shift - the tighter the focus. Remember the detector drives the auto-focus.
The correction uses phase shift countermeasures that are extremely tiny and guarantees the fundamental is now the only thing that can exit the stage. The red shift / blue shift torque is held at a balanced point by a hair trigger which is the velocity detector. All of the correction as I mentioned is done on the horizontal axis. (time domain line). To do this the detector has to be rotated by 90 degrees so that it is literally seen by the music signal as a path that it must travel through to reach the output. (unlike monitoring the voltage or amplitude levels as in the vertical axis).
Trying to use negative feedback driven by amplitude measurements is no way to accurately correct anything. As you may know by the time you get this "sample" of output to use as a countermeasure its too late. That "piece" of music already left the circuit as distortion.
By using 90 degree phase detection capable of seeing a micro-degree of phase shift you have plenty of time to fix the problem in real time. Once this process takes over and we know the sensitivity of the detector we know the max deviation from the true fundamental. At this point it is right in the ballpark of the same phase shift you would expect sound to experience traveling through air. (virtually zero).
At this level of phase purity we have emulated the linear property of air. The sound of the unit now seems more like a hole in the wall or portal through which sound waves are allowed to pass through unaltered. The hardware is cloaked.
I ask simply because in the past you've not indicated that you have any means of quantifying this timing thing you talk about. Just so you know, that's a bit of Red Flag.
I like to think that..More than anything....Nelson’s bits of screed on this subject is about avoiding the confrontational projected bias we are reading in this thread.
I refuse to make more than that -- about what he said in print.
To do one’s self a favor, imagine all the people who have contributed in this thread, are in a room with you.
To try and make one’s self behave accordingly. Only then does one put finger to keyboard.
(I can’t even use the word ’you’. Nor should I. It’s far too inflammatory. See what I mean?)
As for zero distortion electronics, not possible, all we can get to if done as well and as perfect as can be.... is a slightly slower slightly darker copy of the original. Imperceptibly darker and imperceptibly slower. Anything else is a lie.
I seriously doubt anybody honestly wants a stack of truly zero distortion electronics
If you had a preference when it comes to watching TV would you reject the newer 4K resolution TV (as opposed to standard / HD) because it is too revealing? If your [home theater] had several boxes that once you replace them with higher quality gear - would you not appreciate a picture that was much clearer and allowing you to enjoy movies etc. with no [visual] distortion?
With most gear you are stuck with some distortion. People are treating this distortion like it was cholesterol (having good and bad versions).
In my mind there are no "good" harmonics. To me they don't belong there and you certainly don't get that mixture at the live concert hall. The only good harmonics if you will are the rich natural occurring harmonics the come out of the musical instruments as part of their sound. Otherwise just get yourself an Aphex Aural Exciter and be done with it. I think that would fall into the category of "art".
Believe me when you hear what music sounds like with no distortion - you are forever hooked.
The only thing harder than trying to develop this technology in the first place is the ability of a listener to describe it to someone who has not heard it.
One of the biggest problems that exists in communication is mixing or confusing facts with opinions. Everybody is entitled to their own opinion - not to their own facts.
You speak as if you are certain of this.
Its not possible (in your opinion) because......why?
I ask simply because in the past you've not indicated that you have any means of quantifying this timing thing you talk about. Just so you know, that's a bit of Red Flag.
Thanks, I appreciate your letting me know what I'm doing wrong. I don't want anyone to think that there is actual snake oil under the hood.
I'm really sorry that there is so much difficulty trying to explain this concept. Even the owners of H-CAT still can't describe what they hear to someone who hasn't heard it. Mostly because all the good adjectives used to describe the sound of a system have been wasted on "good" sounding gear.
When the real deal comes along - people are left speechless.They literally cannot find words to describe it.
If I watched TV I'd want one that replicated looking through a window, not a portal to a different reality where everything pops and moves in hyper-smooth action. I prefer my stereo to be as realistic.
Ironically there is one term that comes close to describing the experience - realistic (or real).
Reality doesn’t look anything like a modern Samsung TV
You speak as if you are certain of this. Its not possible (in your opinion) because......why?
uhhhmmm..the time/space 3d reality issue? The molecular energy transfer issue? Thermodynamics? Brownian motion?
I mean, is there any fathomable reason to state my argument from a 3d-timesapce reality standpoint, which is the arena we are operating in here (presumably)?
energy translation from one system to the next, is lossy.
No compensation system can fix that, it can only falsify.
a perfected system of electronic flow, translation, and representation, if perfected as much as can be...... is inherently lossy according to the rules or molecular fundamentals of it’s operation. A perfected system controls that lossy bit’s intrusion into the scenario, as much as is possible... and it ends up as stated. Slightly darker, slightly slower. imperceptibly so.
the problem is that... we can theorize that perfected slightly lossy system, but can’t really get there as the interference or integration problems with the fundamentals that create the distortions all have temporal constraints of one type or multiples of them. Temporal or phase related, they be.
As soon as you have two particles in proximity and in integration of some sort...instead of one particle on it’s own... this is your fate.
I hold these things to be self evident to the electronically and scientifically well trained who might find themselves in the world of audio.
Any other answer would be illiterate, ill informed, or purposely ’off’ for some given reason (openly stated or hidden).
An audiophile, will, of course (some, anyway), throw money at the first ill informed person who ’gives them more’ ..in the arena of more detail. Which is more usually more distortion of some sort. This is how we end up with entire swaths of gear that are incompatibly screechy, and we end up with systems that drive some right out of the given room. Each piece competing with the last to be ’more revealing’.
wizened audiophiles step away from that stuff and look to the item that is more revealing an at the same time more harmonically rich, more warm in complex textures, more subtle in those aspects. Not screechy overly detailed soundstages that only a madman would call musical. Real music is brash and potent,and unbelievably potent in the transient domain. But is almost never ’bright’, if it is a live acoustic instrument. Neither our brains, the musical instrument, or acoustics -is wired that way. Reproductions tend to fail in delivering these subtle time signatures and rich harmonics in micro/macro transient functions and smear those subtleties and get dark and obscuring and at the same time adds noise as an overly in everything it does. Inescapable phase issues and molecular noise. The reality gig pressing itself into the scenario -- an unavoidable carrier of the reality we know..
In the real world, you can stand beside a drum kit that is being played and have an actual conversation. that’s transients, and low distortion, large and wide dynamic range and noise floors. Live acoustic. Reproductions tend to utterly fail at this all important set of related functions. our systems (seldom heard but they have been to a few shows) can do this incredibly difficult set of tricks. Speakers with such low distortion in critical areas (as a set), that a speaker builder type guy borrowed a set, and blew a driver for the first time in his life. He never heard the limit coming. Not even a hint of any familiarity to hang his educated hearing on. One time we were playing a reggae record, with 126db transients. (simple 3 way- living room type space, treated) we sat at the coffee table in front of that....and talked. Not yelled, but talked. This was all approx 20 years ago. But I digress...we’re not ready to sell that to anyone, yet.
What you seem to describe is just a very complicated feedback and filtering technique.
I just realized there might be some confusion based on your statement.
I want to make it clear when I say that I wanted to remove distortion - I don't mean that I have found a way to literally remove it or "filter out" distortion. The idea of any filter is to catch / remove unwanted things that already exists.
The proper statement should be that I have found a way to prevent distortion from occurring in the first place. I have removed the mechanism needed to create harmonic distortion.
Thanks, I appreciate your letting me know what I'm doing wrong. I don't
want anyone to think that there is actual snake oil under the hood.
Thinking it and Being it are two different things. No-one wants people to think there is snake oil in their stuff. The problem you have is that you refuse to explain your timing theory in any sort of meaningful way that makes sense to anyone with an education. The fact that you have this circuit to do the job for you and at the same time you've not quantified the timing issue is a tale-tale that the circuit either a) does not exist or b) does not work as you think or c) does not work at all and is a fantasy The reason is that the measurements you need are insanely easy to produce- yet in all the years you've made these claims the proof of your claims have been conspicuously absent.
If you want to not be constantly challenged on forums like this one you have to overcome those shortcomings with something real- not just endless text about nothing. Post some measurements that show how your circuit works where others fail. Its simple and easy.
Are you listening Bo, Mr. 3d sound? When we can't actually try your product and hear if what you say is true, we need proof. Not endless posts about your awesomeness.
@roger_paul We met about a decade ago, as you demo’d your components to my audio (Philadelphia) audio group. My feelings of the day were that you were an incredibly nice and gracious person, and we spent a lot of the time talking face to face with one another. Sonically, I felt the overall sound was good, but did not motivate me to pursue things beyond our meeting. So I asked if you felt happy with the sound, and if it represented your products fairly. Pardon me if I’ve misread you, but I’ve understood from your posts that you’ve made significant progress since our meeting, and have come to the point where you feel absolutely satisfied with where things have now landed.
I’ve watched a lot of back and forth in this and other threads, and think Ralph (AtmaSphere), among others, makes his points in a most salient and consistent manner. For whatever reason, the products don’t resonate with most folks outside of Norm (Tbg), and your passion and message somehow fails to get through to this community. From my standpoint, no one’s really getting anywhere in this discussion. And as you are far closer to the end of your road than the beginning, unless something changes in a big way, it seems clear your life’s work and all that you believe in will not see much consideration beyond these discussions.
To that end, here is a proposal...presuming you still are in New Jersey, and amenable to the idea, I’m willing to visit you for an hour or three some afternoon, and have you display your preamplifier and / or power amplifier.
I’ll report my opinions here. Who knows if they will be positive, negative, or neutral? I always say, that’s why they make vanilla AND chocolate. Hopefully, the reputation I’ve built on this site since 1999 has shown my insight won’t be bought or unduly influenced. Just to be completely up front, going in, I feel less interested in the theory and architecture of your designs than the actual sonic results. Normally, if I’m taken by the sound, and feel it’s of merit and value, I will feel intrigued enough to dig into everything else. And if not, there’s little value in spending more time on it.
trelja, Thanks for offering your time to check this out. The only way to understand what I have been trying to share is by actual listening. Please go to my website and use the contact form or email me at info@h-cat.com so I can set this up.
I am willing to have you come by and hear the final version.
Trelja, I am interested to hear what you think of how it sounds. Please move forward with making this happen. An observation of just the preamp and then one of both amp and preamp together would be good, if you can work that out.
I want to see truly perfect measurements under the most grueling load so that when I listen to it I know that what I'm hearing is the sound of perfection
You keep talking about power amps - I'm not. The core building block that is the "cloning amp" is found in phono stages, line stages, power amps (as the voltage gain) and dacs (as the analog output stage) the power amp will not be "perfect" when driving strange loads. It will successfully drive 90% of speakers. You may have some interaction that is introduced by the amp/speaker coupling/matching.
I have been talking about the amplifier process which is the entire chain of components - not just an amp. This is why I offered to have you listen to the line stage.
Besides I'm sure there are perfectly bad sounding power amps that can produce a KW into 2 ohms or have the perfect square wave at the output - so what?
On the one hand you are saying the specs don't mean anything as far as the sound of the amp (tube amps measure poor but sound great) Solid state amps can measure incredibly good but can drive you out of the room when you listen.
In other words perfect specs do not mean a perfect amp. If you examine the core H-CAT amplifier [stage] it has perfect specs and zero distortion. The output stage needed by the power amp to drive the speakers will do its best to maintain the purity that drives it. The power amp has no overall feedback loop (from output to input).
The core process uses tiny amounts of phase correction that can be considered "feedback" because it is a countermeasure but it differs so much from the classic negative feedback because of where it is in the circuit and how it is implemented.
With all due respect, telling people they just need to listen to understand the technical claims is the same thing as you saying "My word is the only proof you need to believe my claims"
That's not what I said
The only way to understand what I have been trying to share is by actual listening.
That's what I said.
You won't gain any technical insight by listening. But you will experience the acoustical result of the process. It is the experience that I'm trying to share.
teo_audio, Can you enlighten me on the time/space 3d reality issue ?
kosst, I don't understand the obsession with the scope and analyzer - didn't we learn that the THD measurements did not correlate with how it sounds?
You've cited no measurements.
There is nothing to measure. Take the line stage for example. You see a test tone at 1khz sitting at 0db out and if you look across the spectrum headed north of 1 khz you see flat constant noise around -110db. If you specifically monitor the 2khz frequency you see that it is also just the noise floor. There are no other "bumps" showing up in the spectrum. Total absence of harmonic distortion. This was my initial proof that I could prevent a circuit from generating harmonics by using a phase based countermeasure circuit directly on the music signal.
Whoa! Holy guacamole! Oh, so this îs what happens when a measurement fanatic encounters someone who disagrees with him? Geez, I was under the impression the whole amplifier measurement thing - especially THD - went out the window 40 count em years ago! As well as the bullet headed dude 🌰 from Audio Review or whatever.
Practically everybody who builds one applies some positive phase second order distortion through the NFB loop balance to warm the sound up and open up the stage.
He doesn't know what a 100% distortion-free amp sounds like. He's never heard one.
I thought that was the whole purpose of his visit.
Unless he has calibrated microphones for ears, oscilloscopes for eyes, and a distortion analyzer for a brain, he cannot substantiate your claims.
My gear is built for humans to enjoy. No cyborgs.
Our ears,eyes and brain are far better than man made test equipment when it comes to making observations. I'm surprised that someone so deeply embedded into specs like yourself would swallow some pride and go for the added distortion needed to make it tolerable. What's up with that?
I never had a customer call me and ask if I could give them a knob on the front panel so they could add a little distortion.
Everybody knows you can manipulate a signal to sound like all kinds of things
Well that is certainly true especially if you have a way of adding your own flavor of distortion.
...even those things you claim your gear does.
Here is where there is a problem. It is the absolute absence of manipulation that makes it distortion-free. You know like air. You must be disappointed when you go to a live concert. Do you bring your own bag of distortion with you? Or wait for the CD version to come out and listen to it at home where the "proper" amount of distortion can be added.
I can't wrap my head around the idea that we need distortion in our playback systems.
Your amplifier circuit by itself (without adding distortion) apparently is making enough mistakes (errors) to warrant having to do something to hide or cover up whats happening.
...applies some positive phase second order distortion through the NFB loop balance to warm the sound up and open up the stage.
Translation: without adding second order - the raw circuit is "cool " sounding and has a narrow or restricted sound stage. Yes?
Sorry my bad. So I guess that the raw circuit is fine by itself. Its just that if you want to make the sound even richer and fuller than the original recording - then you add the extra distortion.
This also gives you the added bonus of listening to the performance on a larger or wider sound stage than the one they actually used for the recording?
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