LSA Voyager GAN Amplifier

Just explaining ASR to folks who don’t understand what it’s all about. There’s been lots of talk here on this thread about ASR before I arrived.

Would there  be harmonic distortion from a 15khz tone that humans could hear or a band limited amp would amplify?

@djones51  No. The reason that tone is used is to look for intermodulations. Those can be quite a bit lower in frequency depending on what other tones are used in the test. How well it does with this test can say a lot about how relaxed/easy going the amp is to listen to since intermodulation distortion is very audible.

The point of the 15khz tone is to see if the amp struggles with those frequencies. As most amps have a much harder time as the frequency climbs above 1khz.

I seriously doubt any class D amp would 'struggle' with a 15KHz tone. If they are at all competent, the amp would just sit there and do it all day. 

I agree with the rest of this quote though- most amps have insufficient feedback owing to insufficient gain bandwidth product to support the feedback at higher frequencies- so the distortion often rises above 1KHz (contributing to harshness and brightness). I think this might be why distortion is often measured at only 100Hz, so as to cover up that issue. I agree that the spec sheets are mostly marketing tools because they almost never tell you any of the more meaningful information, such as you pointed out above ('...THD+N vs power vs frequency over a 20-20k bandwidth'). Such a graph would instantly show who has the gain bandwidth product and who doesn't. Heaven help us if the spec sheets actually showed something useful...

Heaven help us if the spec sheets actually showed something useful...

Hypex and Purifi offer quite a bit of performance data on their amp products, much more than most.

So this is what I have picked up here reading @mivmike mikes posts.

1. He is amplifierdude and audio2design and has been banned several times.

2. He is a narcissist

3. He is a sociopath

4. He need help with his ASRDS

5. We need that mute user button.

Keep adding value Jerry. Not sure what this forum would do without your vast expertise. 

There is my boy @amplifierdude 

What a dud!

@mivmike

You just do not understand what you post.

The Hypex graph above is at one power level, 5 watts or about 1% of it’s output. There is about a 15-16db change from 200-20Khz. I don’t know what is happening below 200, seems all over the map. Even at 5W, the Topping only has about a 20db change from 20Hz - 15KHz. That is not much different from the Hypex.

If you test the Topping at 1%, or about 1W, then it has only about 2 or 3db change over 20Hz - 15KHz. That is quite a bit better than the Hypex.

You could choose to stop posting stuff that gets holes blown in it. Or not.

Hypex and Purifi offer quite a bit of performance data on their amp products, much more than most.

They do- and are the exception rather than the rule. Bruno uses a self-oscillating technique where the phase margin of the circuit is exceeded by all the feedback added- and so goes into oscillation. The oscillation is then used as the switching frequency- and the triangle wave derived from it. So that allows for 50dB or more of feedback even at 15KHz. You can see this in the distortion vs frequency curves.

 

You just do not understand what you post.

The Hypex graph above is at one power level, 5 watts or about 1% of it’s output. There is about a 15-16db change from 200-20Khz. I don’t know what is happening below 200, seems all over the map. Even at 5W, the Topping only has about a 20db change from 20Hz - 15KHz. That is not much different from the Hypex.

If you test the Topping at 1%, or about 1W, then it has only about 2 or 3db change over 20Hz - 15KHz. That is quite a bit better than the Hypex.

You could choose to stop posting stuff that gets holes blown in it. Or not.

Obviously I understand that one is power vs distortion at multiple frequencies measured individually. And the other is THD+N vs frequency over the entire bandwidth. Which is a very useful test that should have been included in the Topping review. But it wouldn’t have been pretty. There’s a 20dB difference in noise and distortion at 5w between 1khz and 15 with the Topping! Only 20dB? 20dB is loads! with the Hypex it’s flat as a pancake. And thats a 10 year old amp design!

And with the Topping by 50w output its a 35dB spread! Horrible performance!

But the Topping is still the 2nd best amp in the world according to your mentors.

There’s a 20dB difference in noise and distortion at 5w between 1khz and 15 with the Topping!

But still the 2nd best amp in the world according to your mentors.

@mivmike , there is a 15-16 db difference with the Hypex. 20*log(0.15/0.025) = 15.6db. That is not much different from 20db w.r.t. distortion.  Amir does not know nearly enough to be a mentor to me, and there are many on ASR with more knowledge and experience, all of which is meaningless. This is about your posts.

I could be your mentor if you took the time to understand what I am writing. Here is another mentoring for you. The Topping is -75db distortion at 5W, 15KHz. That is 0.017%. That is almost exactly the same as the Hypex at 0.015%. At lower frequencies, the Topping is even better than the Hypex. Of note, the ASR graph is 45KHz BW, so after about 10KHz, the THD will not be audible to anyone, and for most here I expect that will be the case at close to 7-8KHz.

I admittedly read the graph wrong, however, you may want to reconsider making libellous statements like this:

Either way Amir should have used that THD+N vs frequency @ 5w test in the Topping review, with the Hypex, Purifi and Benchmark amps overlaid in the background. But that would be poor marketing for his partners at Topping. Which means less commission for Amir from the sales generated by the review.

I admittedly read the graph wrong

Admitting is a good 1st step

So what in the Purifi module makes it have less hysteresis distortion? The NC500 and the Purifi use the same FERRITE core coils.....and the Purifi have STEEL leads on their output caps. What Bruno claims is that there is so much feedback around the coil that it "gets rid" of the ferrite/steel sound. The Purifi has even more feedback than the NC500. What do you think, oh all knowing one?

What do you think, oh all knowing one?

while I am not all knowing I do know that Bruno knows more about class d amp design than all the tweakers combined x 10,000.

it’s the peak of stupidity to think any tweaker is going to swap a few parts and improve something Bruno designed.

Need to change the name of this thread to the Bruno and Lars Class D Purfi Cult.

Clearly he knows more about business than @mivmike er @amplifierdude .

I did my homework......in fact, the article you refer to was a retort to an email I sent him.  He claims his super feedback gets rid of hyteresis and to prove it he created some test that proves nothing (except a measurement).  What do you think?....instead of quoting him.....since he says basically nothing.  BTW even all ferrite core coils sound different from each other.  If you made the very coil he uses out of purer wire it would sound better.....if you cryoed it....it would sound better.  If you use a toroid coil instead of an incased coil it would sound different.  So, what is the best?  Did you do extensive listening tests to coils to know......or do you believe all coils sound the same?  I told Bruno the only way you would know if you got rid of the hysteresis in a ferrite coil would be to A/B his coil with an air core coil and listen.  This is how you know somethng.....by actual listening tests......not by a made up measurement test that has no basis in sound quality. 

This game is so much more complicated than a simple measurement or a guess.  You have to listen to everything you do......to really know if what you "think"...is what is "real"....and what is real in audio.....is what sounds most transparent.....and only the ear can judge that.

It is the peak of stupidity to think that you cannot swap a few parts and improve something Bruno designed.  If Bruno listened to everything he did and was all knowing.....then maybe not.  He does not listen to everything he does and is not all knowing.  It is stupid to think otherwise.

Obviously, you "only Bruno is God" worshippers  think as you do.  I think everyone is God.....so I worship everyone.  Every thing and every person contributes to the whole.  All souls are pure and lovely.....knowledge is vast and infinite....no one person can hold it all.  We need each other......Tweakers need engineers....Engineers need tweakers.  We are one....most holy ones.

So now we are down to my module is better than yours......what are we...children on a playground? "my dady can beat up your dady" What i am always saying....is that there is more. always more. If you gave me your Frankenstein front end circuit....I could mod it and make it better.....so could a whole host of other people. You do not know everything......no one does. There are tons of people who can improve on what I do. What I do is the result of over 40 years of listening tests and making products and modifications. However, it is but a grain of sand in the knowledge of all things audio......plenty of people know more than me......plenty.......but, my overall knowledge is very, very high......and what I do is appreciated by most everyone......I am in service. I love everyone.

The new Purifi module should get delivered in Dec. Warren at VTV has some Beta ones and says they are a noticeable improvment on the baby one. It makes sense....it has more capacitance in the power supply, a larger output coil, more connector pins in parallel for more surface area and lower impedance and has more current capability so will drive lower impedances even better. Even with a simple non low impedance speaker load Warren thinks it just plain sounds more "real" This is a good thing.

"my daddy can beat up your daddy"

Betting that Mike has never met his Daddy.

I told Bruno the only way you would know if you got rid of the hysteresis in a ferrite coil would be to A/B his coil with an air core coil and listen. This is how you know somethng.....by actual listening tests......not by a made up measurement test that has no basis in sound quality.
 

Measurements are objective, they have no bias. They have a basis in reality, unlike subjective listening that varies from person to person. If there was one best sound, there wouldn’t be so many different and successful amps in the market place. Your idea of good sound is just that, your idea. It has no basis in reality for anyone else. Eye witness testimony has been proven time and again to be unreliable. Your ear witness testimony is flawed for the same reason. At least Bruno delivers an honest product that delivers as advertised, rather than some magic guru fantasy tweak that simply, at best, just adds more noise to the signal.

If Bruno listened to everything he did and was all knowing.....then maybe not.  He does not listen to everything he does and is not all knowing. 
 

Bruno produces products that amplify a signal as cleanly as possible. If people like distortion, they can add it themselves in any flavor they prefer. He doesn't push his subjective tastes on others and claim he knows what sounds "best" -he isn't all knowing but he does know that. I can't say the same for you.

@mivmike -- you didn't even know how to use it 3 days ago, sure your stuff went up ...

Blah, Blah, Blah went the "We don’t need to listen to know something" sheep.

You guys are soooooooooooo much fun!  Love you.

@ricevs 

Don't expect to get respect from Bruno when he knows what he is talking about and you do not. Hysteresis in the inductor is just yet another form of non linear distortion, like any other distortion. If you apply negative feedback it gets reduced by a compensatory amount, and his amps have a lot of feedback because the can.

The inductor is in the feedback loop, hence any hysteresis distortion is drastically reduced by the feedback.

He is not saying it does not exist at some point in the circuit, he is saying that he effectively eliminates its audible effects, which is self evident from the distortion measurements.

@mivmike -- you didn't even know how to use it 3 days ago, sure your stuff went up ...

Yeah I've only had the unit for 3 years and designed several products with it. But someone who's never used one before knows better. And before I bought one I worked with people who did. 

Don't expect to get respect from Bruno when he knows what he is talking about and you do not.

This....

 

Don't expect to get respect from Bruno when he knows what he is talking about and you do not. Hysteresis in the inductor is just yet another form of non linear distortion, like any other distortion. If you apply negative feedback it gets reduced by a compensatory amount, and his amps have a lot of feedback because the can.

The inductor is in the feedback loop, hence any hysteresis distortion is drastically reduced by the feedback.

He is not saying it does not exist at some point in the circuit, he is saying that he effectively eliminates its audible effects, which is self evident from the distortion measurements.

You just learned about hysteresis distortion tonight from the articles I shared. And you're already an expert!

@mivmike 

You really need too learn more, and type less.

They Hypex modules have the inductor in the feedback loop. The Purifi are an advancement, but they are just "better" not architecturally that much different, not even the components are that substantially different. They are an evolution not a revolution.

Again, you cannot tell you got rid of the hysteresis by measurements. More feedback will lower the distortion number....does not mean there is no longer hysteresis. Is hysteresis even measureable? There is no correlation to any measurement and reduction of AUDIBLE hysteresis. You have to listen to really know something......sorry, just the way it is. NOTHING is self evident from distortion measurements.......except a measurement. There is zero correlation between measurements and the sound of electronics........please, again, i beg you to show me the double blind listening test results that show a correlation between measurements and sound quality.........where are they? In your mind......Its all in your mind. We must listen to know something.

I don’t need his or your respect from your minds opinions. I respect myself. I love myself. I am worthy. What I know is what I experience. I trust my experience and my ears. I am not other directed. I don’t need the praise of someone else....except the real praise that comes from the heart. I love Bruno.....he loves me. What we think in our minds is just thoughts.......usually ego based. The soul just loves. I love you, I love Bruno, you love me....Bruno loves me......this is truth....eternal truth.

There is zero correlation between measurements and the sound of electronics........please, again, i beg you to show me the double blind listening test results that show a correlation between measurements and sound quality.........where are they?


 

You just don't get it- you can't correlate something objective like actual measured physical phenomena like distortion with something subjective like "good sound", by definition. Yes, "good sound" is all in your head, and only yours.

NO, you don't get it.  Good sound is good sound.  Measurements have no sound.  They are just in your head. 

We could go on and on......the basic objectivist versus subjectivist game.......I am stopping now......why don't you do likewise.....I am sure that you will want the last word though......have at it......no matter what you do.....eternal love and joy still exists in the now.  Please tune into it for all our sakes.

@ricevs 

Again, you cannot tell you got rid of the hysteresis by measurements. More feedback will lower the distortion number....does not mean there is no longer hysteresis. Is hysteresis even measureable? There is no correlation to any measurement and reduction of AUDIBLE hysteresis. You have to listen to really know something......sorry, just the way it is. NOTHING is self evident from distortion measurements.......except a measurement. There is zero correlation between measurements and the sound of electronics........please, again, i beg you to show me the double blind listening test results that show a correlation between measurements and sound quality.........where are they? In your mind......Its all in your mind. We must listen to know something.

If you insist on being detached from reality then it will be impossible for us to have a meaningful conversation. Absolutely hysteresis will show up in a distortion test, especially any IM distortion test. It should be self evident. If it is not, there is not much i can do to help you. I suggest studying hysteresis more and perhaps modelling it in an electronic circuit. There are mathematical models that are half decent and that you could plug into spice and see what happens.

Any distortion in the feedback loop is going to be influenced by negative feedback. that is what negative feedback does. It is analog error correction. And since you can measure the distortion before and after, especially IM distortion, it is very easy to know what the feedback does to the distortion. You not understand this does not make it incorrect, it just means you do not understand this.

If you did the simulation, or even built a test circuit and measure it, you would see what the distortion products look like. From that, knowing the level and order of even and odd harmonics, you can relate how that may sound, from the tons of psycho acoustic studies into distortion, to the average person. This is science, but not rocket science. Again, you not knowing this does not make it not true, it just means you do not know it.

I can't tell you specifically how any given person is going to behave to a specific distortion signature, but I can certainly make generalizations that will be highly accurate across a wider population of listeners. That is why we know added distortion, even added noise can result in pleasing listening impressions, or false sense or loudness, or harshness or ....  Because while we are different, we are also very similar.

So here is my question. If these Purfi equipped amplifiers are so great why is it I returned my NAD M33 after 45 days because it sounded awful?

But Bruno said……I had it Driving QLN Prestige 5s and could not wait to put my X200 back in the system.

Right now I have the Bel Canto ref501S in my system and sounds fantastic, better than the Mini GaN5 or my Orchard Mono’s.

So here is my question. If these Purfi equipped amplifiers are so great why is it I returned my NAD M33 after 45 days because it sounded awful?

Simple: because we have different tastes and one size does not fit all. Awful to you is awesome to someone else.

Think of Bruno as a modern vintner. He grows grapes, measures the sugar content, the acidity, etc. that he knows produces what he wants. He measures. He tests. He produces a wine based on his knowledge of chemistry as it relates to wine. Of course, as he has said many times, he also tastes (listens). Science got him there, his palate confirms it. Not all like it- because tastes differ. Some claim they can add some root beer to it and it tastes better. To some people, it might. To others, not so much.

Simple you had not been saying that for 2 days on this thread you two clowns hijacked.

It is all graphs and crap. Guessing we are seeing right through you two.

So why cant that be the case with Rick upgrading these amps?

You guys are real hypocrites.

I will not give Bruno a single thought and will never own another piece of his junk again.

Think you have crush boy.

@jerryg123 that is a rather toxic rant on your part and really unwarranted. By any measure, the Purifi modules set an incredible standard for state of the art in amplification not just at their price, but at almost any price.

It's like photography. Bruno created an 100 megapixel camera, with super high dynamic range, incredible optical resolution, and perfect color rendering, and he did it for $2,000.  Now some people are really offended by this, both because it is so much better than what they own, but also because the plebs can now own something better than what they have. They could just buy it themselves, but then that would require accepting its superiority.  Then there are a different group of people who love, for whatever troubles it may have, the look of film, grain, inconsistencies, lower effective resolution and all. They like their colors a bit more vivid and skewing to red, and they like their images a bit softer. Bruno's new camera is not for them.

Which photographer are you @jerryg123 ?

that is a rather toxic rant on your part and really unwarranted

Go to your safe space then.

Buh Bye Cindy. er Andy

I will not give Bruno a single thought and will never own another piece of his junk again.

 

I'm sure there is something out there for you that sounds great in a cave.

@kuribo , it does not appear possible to have an adult conversation. That would require people to behave like adults. You tried.

So why cant that be the case with Rick upgrading these amps?

he doesn't upgrade, he modifies. And almost certainly based on his lack of fundamental knowledge of the circuitry, he degrades their performance to suit his own version of "good sound", fidelity to the input signal be damned.