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Hypex performance paper


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I was looking at this 'paper' published by Hypex:

 

http://www.hypex.nl/docs/appnotes/IMD_appnote_.pdf

 

In Conclusion

The reason why we characterise the performance of our amplifiers using only THD and CCIF IMD is

because UcD has:

- Constant loop gain

- No input distortion

- Negligible slew rate artifacts up to 20kHz full power (even though its power bandwidth is

“only” 35kHz)

and is therefore fully characterised using only these two simple tests. Life is complicated enough.

 

 

Can anyone explain if this makes any sense?

 

It sounds suspiciously like they are trying to devaluate the shortcomings of their technology...

 

R

"Science draws the wave, poetry fills it with water" Teixeira de Pascoaes

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Money corrupts people, and marketing is sometimes as much about lies that can be sold as anything.

 

I don't suppose anything in that paper is technically flat out wrong. However, I agree with the OP, the style is one that doesn't sit well with me. Certainly not about transparency.

 

Among other things the idea we do these couple of numbers because more is confusing and bothersome to do. Come on, with modern test gear that isn't really true. Why not give customers all the info you can, you know a designer like Bruno has done all the testing available. He believes in and designs by those results. Why not just include it? Because Bruno has been seduced by the high end easy money game. His target customers don't want to be bothered or confused. Bruno in his finished products is at the expensive end of the pool. Those customers want a couple numbers of confirmation and the spiel in that paper to comfort them. They have money and just need to be lead to the idea in the right way this is a special piece of gear, just hook it up and listen to how good it is.

 

So Bruno is moving from the all encompassing technical design guy, to one who can reassure his customers he is a top designer. It is to his benefit to begin smoothing over the technical details so he can sale the particular special magic that is his at high prices to waiting customers.

 

I suspected he had gone over so to speak when he started selling moderately expensive cabling with silver and teflon. He had written an article about how cabling is not an issue, and went to some length to show silver and teflon was a bad combination due to an unusually large tribo-electric effect. Though otherwise in general cable was cable at audio frequencies. So why then make and sell expensive cable made just that way and explain he went to pains to produce it to prevent just that triboelectric issue from being a problem? Money....is why.

 

I guess being more charitable he is the smart engineer:

 

spinal_tap_amps.png

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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It's very sad to note that the high-end market is increasingly changing it's goal from accurate reproduction to pleasing low-expectation undemanding rich costumers. And the critics/magazines are playing along...

 

R

"Science draws the wave, poetry fills it with water" Teixeira de Pascoaes

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Since 1972, Accuphase build amplifiers and continue to do so today. From this document, an extract on why Accuphase does not manufacture a Class D amplifier.

 

Werner: “Besides Streaming Audio, there is this other novelty called Class D amplification, that is gaining a lot of popularity. Has Accuphase looked into this technology yet, and what are your findings? Is it possible that we will see Accuphase products with this technology in the near future, and if not, why?”

 

This question causes some mild excitement among the otherwise relaxed looking delegation. This time it is chairman Saito himself who answers, in impeccable English.

 

“Class D is not strange to us. In fact, in the past we have built the 6-channel PX-650 amp that used this technology, but we stopped using Class-D technology shortly after that. The main problem of Class-D, even today, is the relatively high noise-floor caused by the relatively low carrier frequency. That carrier-frequency is inherent to this technology and it always gives you more distortion and a certain unrest in your playback, compared to a well-designed conventional circuit. Everyone who is given the opportunity to compare to a Class D circuit and a conventional circuit in a well-prepared and conscientiously performed listening test will hear the differences immediately. Especially with our newest generation of conventionally designed components, we have taken another big step on the path towards truly realistic playback. Because we have been able to lower the noise-floor with every new generation, the music gets a truly breathtaking sense of softness and realism.”

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Not sure what the fuss is about. Pulling another quote from the beginning of the piece (which is by the way not a "paper," but rather an "Application note" for potential customers of UcD modules, i.e., audio companies or DIYers, thus quite sophisticated users):

 

It’s often proposed that IMD and especially DIM tests produce objective corroboration for certain sonic mysteries surrounding different amplifier topologies. The idea is that more complicated signals will suddenly bring out the beast in an amplifier that measures like an angel THD wise. I’m not that convinced.

 

Then at the start of the next section explaining why he (Bruno) isn't convinced IMD numbers will tell us more than THD:

IMD and THD products are generated in exactly the same way.

 

Can someone explain to us whether and how Putzeys is technically incorrect?

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical to EtherREGEN -> microRendu -> ISO Regen -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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Since 1972, Accuphase build amplifiers and continue to do so today. From this document, an extract on why Accuphase does not manufacture a Class D amplifier.

 

Werner: “Besides Streaming Audio, there is this other novelty called Class D amplification, that is gaining a lot of popularity. Has Accuphase looked into this technology yet, and what are your findings? Is it possible that we will see Accuphase products with this technology in the near future, and if not, why?”

 

This question causes some mild excitement among the otherwise relaxed looking delegation. This time it is chairman Saito himself who answers, in impeccable English.

 

“Class D is not strange to us. In fact, in the past we have built the 6-channel PX-650 amp that used this technology, but we stopped using Class-D technology shortly after that. The main problem of Class-D, even today, is the relatively high noise-floor caused by the relatively low carrier frequency. That carrier-frequency is inherent to this technology and it always gives you more distortion and a certain unrest in your playback, compared to a well-designed conventional circuit. Everyone who is given the opportunity to compare to a Class D circuit and a conventional circuit in a well-prepared and conscientiously performed listening test will hear the differences immediately. Especially with our newest generation of conventionally designed components, we have taken another big step on the path towards truly realistic playback. Because we have been able to lower the noise-floor with every new generation, the music gets a truly breathtaking sense of softness and realism.”

 

Yes, Bruno's first act of hi-fi apostasy was to design Class D amplifiers. His second was to double down by using another verboten technology, negative feedback, to reduce the noise floor Accuphase is complaining about. What he got as a result are Class D amplifiers with measurements as good as or better than conventional amps, while being smaller, lighter, and heaps more efficient. Oh, and people say they have great sound quality as well.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical to EtherREGEN -> microRendu -> ISO Regen -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment
Since 1972, Accuphase build amplifiers and continue to do so today. From this document, an extract on why Accuphase does not manufacture a Class D amplifier.

 

Werner: “Besides Streaming Audio, there is this other novelty called Class D amplification, that is gaining a lot of popularity. Has Accuphase looked into this technology yet, and what are your findings? Is it possible that we will see Accuphase products with this technology in the near future, and if not, why?”

 

This question causes some mild excitement among the otherwise relaxed looking delegation. This time it is chairman Saito himself who answers, in impeccable English.

 

“Class D is not strange to us. In fact, in the past we have built the 6-channel PX-650 amp that used this technology, but we stopped using Class-D technology shortly after that. The main problem of Class-D, even today, is the relatively high noise-floor caused by the relatively low carrier frequency. That carrier-frequency is inherent to this technology and it always gives you more distortion and a certain unrest in your playback, compared to a well-designed conventional circuit. Everyone who is given the opportunity to compare to a Class D circuit and a conventional circuit in a well-prepared and conscientiously performed listening test will hear the differences immediately. Especially with our newest generation of conventionally designed components, we have taken another big step on the path towards truly realistic playback. Because we have been able to lower the noise-floor with every new generation, the music gets a truly breathtaking sense of softness and realism.”

 

Out of date. Now wrong.

 

First, carrier frequency at some of the better brands has increased.

 

Second the quote,

Everyone who is given the opportunity to compare to a Class D circuit and a conventional circuit in a well-prepared and conscientiously performed listening test will hear the differences immediately.

 

Just isn't true. Read recent reviews (last 2 years) of new Class D amps - at least the better ones - and you will find both professional and audiophile reviewers who say that they are as good as, and in some ways better than, many conventional amps, even costly ones. No one has yet said that the worlds best amp is a class D model, buy many experienced listeners have concluded that there are Class D amps that are as good as any conventional amp in their price range, and even - for some of them - that a multiple 5 figure dollar price is what is needed in order to better them with a conventional amp.

 

If we are limiting the comparison to conventional amps costing $20k and more, then maybe he's correct.

Main listening (small home office):

Main setup: Surge protector +_iFi  AC iPurifiers >Isol-8 Mini sub Axis Power Conditioning+Isolation>QuietPC Low Noise Server>Roon (Audiolense DRC)>Stack Audio Link II>Kii Control>Kii Three >GIK Room Treatments.

Secondary Path: Server with Audiolense RC>RPi4 or analog>Cayin iDAC6 MKII (tube mode) (XLR)>Kii Three .

Bedroom: SBTouch to Cambridge Soundworks Desktop Setup.
Living Room/Kitchen: Ropieee (RPi3b+ with touchscreen) + Schiit Modi3E to a pair of Morel Hogtalare. 

All absolute statements about audio are false :)

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If we are limiting the comparison to conventional amps costing $20k and more, then maybe he's correct.

 

I'll disagree with that since the NC400's forced me to sell some 300wpc Class A amps (Clayton Audio). I couldn't tell a difference when blind whatsoever. Oh, that's right, they're "only" $16,500.

W10 NUC i7 (Gen 10) > Roon (Audiolense FIR) > Motu UltraLite mk5 > (4) Hypex NCore NC502MP > JBL M2 Master Reference +4 subs

 

Watch my Podcast https://www.youtube.com/channel/UCXMw_bZWBMtRWNJQfTJ38kA/videos

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I'll disagree with that since the NC400's forced me to sell some 300wpc Class A amps (Clayton Audio). I couldn't tell a difference when blind whatsoever. Oh, that's right, they're "only" $16,500.

 

NC400 or NC1200 (looking at your sig), or first the former, then the latter?

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical to EtherREGEN -> microRendu -> ISO Regen -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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NC400 or NC1200 (looking at your sig), or first the former, then the latter?

 

The new ATSAH NC500 is said by the company to give 95% of the performace of their NC1200 based amps for a fraction of the price.

The company making the NORD NC500 based amps has developed their own input section (not the NCore one), they claim their unit is better than the ATSAH NC500.

Main listening (small home office):

Main setup: Surge protector +_iFi  AC iPurifiers >Isol-8 Mini sub Axis Power Conditioning+Isolation>QuietPC Low Noise Server>Roon (Audiolense DRC)>Stack Audio Link II>Kii Control>Kii Three >GIK Room Treatments.

Secondary Path: Server with Audiolense RC>RPi4 or analog>Cayin iDAC6 MKII (tube mode) (XLR)>Kii Three .

Bedroom: SBTouch to Cambridge Soundworks Desktop Setup.
Living Room/Kitchen: Ropieee (RPi3b+ with touchscreen) + Schiit Modi3E to a pair of Morel Hogtalare. 

All absolute statements about audio are false :)

Link to comment
The new ATSAH NC500 is said by the company to give 95% of the performace of their NC1200 based amps for a fraction of the price.

The company making the NORD NC500 based amps has developed their own input section (not the NCore one), they claim their unit is better than the ATSAH NC500.

I have NC500's...

W10 NUC i7 (Gen 10) > Roon (Audiolense FIR) > Motu UltraLite mk5 > (4) Hypex NCore NC502MP > JBL M2 Master Reference +4 subs

 

Watch my Podcast https://www.youtube.com/channel/UCXMw_bZWBMtRWNJQfTJ38kA/videos

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Yes, Bruno's first act of hi-fi apostasy was to design Class D amplifiers. His second was to double down by using another verboten technology, negative feedback, to reduce the noise floor Accuphase is complaining about. What he got as a result are Class D amplifiers with measurements as good as or better than conventional amps, while being smaller, lighter, and heaps more efficient. Oh, and people say they have great sound quality as well.

 

Some measurements are standard for a reason and despite this he not only chooses not to perform them but questions their effectiveness.

My guess is that his products don't perform well in those measurements but I could be wrong.

 

R

"Science draws the wave, poetry fills it with water" Teixeira de Pascoaes

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Some measurements are standard for a reason and despite this he not only chooses not to perform them but questions their effectiveness.

My guess is that his products don't perform well in those measurements but I could be wrong.

 

R

 

Ah. This UcD module is based on similar design principles to other products that measure well, and Bruno has as noted previously always been a maverick who questions conventional wisdom, but in this instance I suppose it is possible he is pretending to be a maverick in order to cover something up (at least until customers obtain the item, since many manufacturers and DIYers are capable of running tests themselves).

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical to EtherREGEN -> microRendu -> ISO Regen -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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Some measurements are standard for a reason and despite this he not only chooses not to perform them but questions their effectiveness.

My guess is that his products don't perform well in those measurements but I could be wrong.

 

R

 

I'll disagree with this too as I've had the amps measured by someone who has zero bias. The measurements in his words are "incredible".

W10 NUC i7 (Gen 10) > Roon (Audiolense FIR) > Motu UltraLite mk5 > (4) Hypex NCore NC502MP > JBL M2 Master Reference +4 subs

 

Watch my Podcast https://www.youtube.com/channel/UCXMw_bZWBMtRWNJQfTJ38kA/videos

Link to comment
Some measurements are standard for a reason and despite this he not only chooses not to perform them but questions their effectiveness.

My guess is that his products don't perform well in those measurements but I could be wrong.

 

R

As I have already said, I believe he is marketing to a different group. However, every indication is his products measure superbly in all the usual tests. So I don't believe he is covering up for performance problems as there don't seem to be any.

 

Sent from my Nexus 6P using Computer Audiophile mobile app

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

Link to comment
I'll disagree with this too as I've had the amps measured by someone who has zero bias.

 

Yes, only Class A amp designers have bias. ;)

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical to EtherREGEN -> microRendu -> ISO Regen -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

Link to comment
Out of date. Now wrong.

 

First, carrier frequency at some of the better brands has increased.

 

Second the quote,

 

Just isn't true. Read recent reviews (last 2 years) of new Class D amps - at least the better ones - and you will find both professional and audiophile reviewers who say that they are as good as, and in some ways better than, many conventional amps, even costly ones. No one has yet said that the worlds best amp is a class D model, buy many experienced listeners have concluded that there are Class D amps that are as good as any conventional amp in their price range, and even - for some of them - that a multiple 5 figure dollar price is what is needed in order to better them with a conventional amp.

 

If we are limiting the comparison to conventional amps costing $20k and more, then maybe he's correct.

 

I can't agree with your opinion, that's nothing unusual though.

AS Profile Equipment List        Say NO to MQA

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It's very sad to note that the high-end market is increasingly changing it's goal from accurate reproduction to pleasing low-expectation undemanding rich costumers. And the critics/magazines are playing along...

 

R

 

Can you give me an example of that? I'm not saying you are wrong, I'd just like to know how you come to that conclusion.

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Based on some cursory internet reading, many are saying a THD rating through the 20-20 audio band of less than 3% is inaudible. Most of the amps I look at even in the "budget" audiphile category are much less than this, .1% or better usually. Class D amps tend to be even less (.01%, etc.), and have even better SNR than similar priced amps of A/B typologies. I am reading all this to mean that these amps are very quiet and add almost no distortion, and none that can actually be heard.

 

Anyone agree or disagree with my little summary - what am I missing?

Hey MQA, if it is not all $voodoo$, show us the math!

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Based on some cursory internet reading, many are saying a THD rating through the 20-20 audio band of less than 3% is inaudible. Most of the amps I look at even in the "budget" audiphile category are much less than this, .1% or better usually. Class D amps tend to be even less (.01%, etc.), and have even better SNR than similar priced amps of A/B typologies. I am reading all this to mean that these amps are very quiet and add almost no distortion, and none that can actually be heard.

 

Anyone agree or disagree with my little summary - what am I missing?

Class D amps have output filters which can react with speaker loads for some odd responses. I don't think you can make a blanket case for 3% being inaudible. They are very, very quiet. Large powerful models have output levels in the few microvolts. And yes at anything less than max power they have very low levels of distortion.

 

Sent from my Nexus 6P using Computer Audiophile mobile app

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

Link to comment
Class D amps have output filters which can react with speaker loads for some odd responses. I don't think you can make a blanket case for 3% being inaudible. They are very, very quiet. Large powerful models have output levels in the few microvolts. And yes at anything less than max power they have very low levels of distortion.

 

Sent from my Nexus 6P using Computer Audiophile mobile app

 

Class H topology (e.g. BASH) get's around the filter design/implementation problem of Class D (allegedly the hardest part of a good Class D implementation) by using a switched power supply to power a Class A/B circuit - sort of having an amplifier power an amplifier if I understand correctly...Do I?

Hey MQA, if it is not all $voodoo$, show us the math!

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Class H topology (e.g. BASH) get's around the filter design/implementation problem of Class D (allegedly the hardest part of a good Class D implementation) by using a switched power supply to power a Class A/B circuit - sort of having an amplifier power an amplifier if I understand correctly...Do I?

 

Close enough I suppose. Similar to what Bob Carver did with some of his designs. However, the thread is about HypeX which is class D in what they call an H bridge. The paper at the top of this thread even mentioned the filter at 35 khz.

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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