Hypex Nilai500DIY Amplifier Review

[restorer-john]

Indeed.

Really? Oh, and by the way, that "from the far east" slur... How is that different from all the "designed and assembled in the US (from boards made in China)" products?

View attachment 270564

You should look at what you posted- it only re-inforces everything I said.

No slurs, or should I just specifically mention names. LOL.

You're out of your depth.

 

[Julf]

You should look at what you posted- it only re-inforces everything I said.

Please explain.

No slurs, or should I just specifically mention names. LOL.

The Dutch have the perfect response to "LOL" - "Lul".

You're out of your depth.

But not height. Anyway, nice attempt at ad hominem - usually an indication that someone has lost an argument but refuses to admit it.

 

[barrows]

What's the effect of higher distortion at high frequencies?
Is the amp likely to get harsher at high volume?

Nothing. Note that this test only really shows considerable distortion at high power above 10 kHz! Music signals are never going to require high power at such frequencies, so this distortion will never happen with actual music playback. Additionally, all the distortion harmonics will be out of the audible range. this measurement purely shows the result of engineering choices, and will have no effect whatsoever on the sound of the amplifier playing music.

 

[barrows]

But what else is it good for if it is mediocre above 10kHz, and need to use more watts to sound good? Really heavy driven speakers?

You are wrong, this amplifier is superb throughout the entire audio bandwidth.

 

[Ra1zel]

It's time for us to to increase the measurement bandwidth to exahertz to finally find out the influence of stray cosmic rays on the millionth harmonic.

Maybe this will finally satisfy some ASR dwellers obsession with the irrelevant.

 

[AaronJ]

Here we go again...

The standard power and distortion ratings are for a typical audible spectrum between 20Hz and 20,000Hz.

Such has been the case for many decades, and indeed, is still required for advertised specifications. A strict range of frequencies and range of power outputs (250mW to rated power) over which the amplifier can deliver its rated power and rated distortion at any frequency. Not just one frequency where the number looks good for the spec sheet.

Hypex/Purifi and some others from the far east thumb their noses at this. Their specifications are non-compliant in that regard.

They pick 1kHz (easy) and state a THD number. That is their sole claim to fame.
They don't provide a full power bandwidth (-3dB) specification, or state the power and THD over a specified bandwidth with both/all channels driven.

Here's an example of compliant, current specifications from a US manufacturer.
View attachment 270557

The above power output claims, THD claims and IM claims are in accordanced with FTC required standards for advertised ratings. I see even the latest offerings from Schiit are eschewing proper specifications, not specifying loads, frequency range, distortion clearance range or numbers of channels driven. Hopefully they will clean up their act too.

Anyway, there's plenty on ASR and plenty of discussion in relation to this. Cheers.

Who makes the amp referenced in this post?

 

[Calleberg]

Who makes the amp referenced in this post?

I will bet my left testicle on that being a Mcintosh amp.

 

[restorer-john]

I will bet my left testicle on that being a Mcintosh amp.

The "Power Guard" spec is the giveaway.

 

[Rick Sykora]

Here we go again...

The standard power and distortion ratings are for a typical audible spectrum between 20Hz and 20,000Hz.

Such has been the case for many decades, and indeed, is still required for advertised specifications. A strict range of frequencies and range of power outputs (250mW to rated power) over which the amplifier can deliver its rated power and rated distortion at any frequency. Not just one frequency where the number looks good for the spec sheet.

Hypex/Purifi and some others from the far east thumb their noses at this. Their specifications are non-compliant in that regard.

They pick 1kHz (easy) and state a THD number. That is their sole claim to fame.
They don't provide a full power bandwidth (-3dB) specification or state the power and THD over a specified bandwidth with both/all channels driven.

Here's an example of compliant, current specifications from a US manufacturer.
View attachment 270557

The above power output claims, THD claims and IM claims are in accordance with FTC required standards for advertised ratings. I see even the latest offerings from Schiit are eschewing proper specifications, not specifying loads, frequency range, distortion clearance range or numbers of channels driven. Hopefully they will clean up their act too.

Anyway, there's plenty on ASR and plenty of discussion in relation to this. Cheers.

I noticed this power spec difference when I first joined ASR. I may not have articulated it well, but @restorer-john has a valid complaint and it does obfuscate power comparisons between amplifiers.

Pretty sure this spec game did not start with Class D or Hypex though. For that matter, ICEPower was my first exposure to Class D and they spec power at full bandwidth. It appears the Hypex UcD modules did too. I traced back to before 2004, and pretty sure the 1 kHz measurement was first used in mid fi (AVR) specs from the larger Japanese brands. As I shopped for a new amp, despite claiming FTC power specs, many more affordable Class AB amps came up shy in overall performance...

ASR leveled the playing field for me. When I was able to compare directly compare my leading contender Class AB amp (Outlaw 2220) to a Hypex (NC252MP) amp, it was pretty clear that the price/performance was clearly in Hypex's favor. Call me selfish if you like, but rather listen to my Hypex/Purifi amps than lament that they do not adhere to the old FTC power spec. I suspect I am not alone.

 

[GXAlan]

I think I like some distortion in my audio. I have tube amps, and I use my Sony TA-ZH1ES over my 120 dB Geshelli amp. I also like my Marantz PM-10 which is very similar to the Nilai thanks to dual NC500OEMs that are bridged.

Only one of two possibilities exists (for me)
1) The high frequency distortion is inaudible when comparing HypeX and other Class AB amps, and it's all sighted bias
2) The HypeX amps sound great because of the high frequency distortion as opposed to "in spite of" the distortion

This graph is common to all of the HypeX products. I have found it more instructive to look at the spectrum since THD+N can be noise or distortion and that composition of that distortion can be insightful.

For simplicity, I am going to measure the power output at 1 kHz and then at the same volume, run the test tones at 1 kHz and 16 kHz. The power output when playing the same test tone at the same volume but at 16 kHz is actually lower. I chose 16 kHz instead of 15 kHz since that's the upper limit of my test tone hearing.

1 watt

5 watts

25 watts

As you increase the power, the 1 kHz test tone is pretty similar but the 16 kHz generates a lot more ultrasonics. But did you look carefully at that last graph?

Let's clean up the noise to see what's going on.

Here, you can see pollution into the audible frequency range. The distortion products are extremely low. Let's keep going up in power.

120 watts

Not sure how the feedback cleans up those ultrasonics -- that's just what it measured.

And finally some test tones at ~5W

CCIF 19/20 kHz

Multitone 3

You can compare that to Sony DSEE processing which adds harmonics...

These harmonics are all "low" from the standpoint of audibility and thresholds. But these measurements are not as clean as Class AB amps which don't have these kinds of ultrasonics. I've never ABX'd my amplifiers since it's going to be hard to allow fast switching with proper volume matching.

However, I wrote this with only the benefit of 1 kHz test tones and real music:
"Switching back and forth, it was pretty clear to me that the Kenwood was a more accurate amplifier that could bring Emma Stone into the room. But no matter how much my brain told me that I should want and prefer the absolute truth and transparency in my gear, I still personal have the preference for a larger-than-life sound and euphonic colorations that I get with the tubes or my Marantz gear -- at least for that specific soundtrack"

"I actually think the Kenwood L-08M beats the Marantz PM-10 for delivering the most narrow phantom center image (specifically for the La La Land Soundtrack) but the PM-10 gives me the chameleon of clean vocals with the tiniest amount of tube warmth with all of the crystalline clarity of classical music where direct comparisons can be made to reality."

With these new measurements and seeing the tube-level distortion for higher frequencies, I think my opinions have some measured correlation. HypeX designs are NOT a straight wire with gain from 20 Hz to 20 kHz. I still really like listening to my HypeX products.

 

[barrows]

I would like everyone here to consider: what are we trying to see here? Considering that music does not have considerable energy in these high frequencies, high power output is never going to be used at high frequencies, except for the possibility that electronic music might have some of this (although no one would ever want to listen to a 15 Khz signal at 100 watts) it would only have this as a test. Additionally, all the harmonics we see here (the distortion products) are well above the audio band, so they are inaudible. I am not sure what the concern here is? If you ask Bruno Putzeys about this behavior as far as the Purifi product goes, I am almost certain he would explain that this behavior is a design choice, that all distortion products are out of the audible range, and that the amplifiers are band limited by design, on purpose, in order to allow for reduced distortion within the audible bandwidth.
There are also quite a few class A/B amplifiers which also exhibit rising distortion with frequency (most of them), go over to stereophile.com and check their measurements of many class A/B amps...
Are we asking these questions just as an engineering exercise? Because, in the real world of listening to music, they are irrelevant to what one will hear.

 

[Julf]

If you ask Bruno Putzeys about this behavior as far as the Purifi product goes, I am almost certain he would explain that this behavior is a design choice, that all distortion products are out of the audible range, and that the amplifiers are band limited by design, on purpose, in order to allow for reduced distortion within the audible bandwidth.

The extreme example of that is of course SACD/ DSD that only has 3-6 dB SNR over the full bandwidth, but thanks to shifting pretty much all the noise to above 22 kHz, achieves decent SNR in the audio band. I don't hear too many complaints about "harsh sound" of DSD....

 

[barrows]

The extreme example of that is of course SACD/ DSD that only has 3-6 dB SNR over the full bandwidth, but thanks to shifting pretty much all the noise to above 22 kHz, achieves decent SNR in the audio band. I don't hear too many complaints about "harsh sound" of DSD....

Agreed. I love DSD, and oversample all my music to DSD 256 using HQPlayer for playback.

 

[Matias]

If you ask Bruno Putzeys about this behavior as far as the Purifi product goes, I am almost certain he would explain that this behavior is a design choice, that all distortion products are out of the audible range, and that the amplifiers are band limited by design, on purpose, in order to allow for reduced distortion within the audible bandwidth.

No need to ask, he already wrote that below, it's just that these people will not read before posting...

Review and Measurements of Purifi 1ET400A Amplifier

So what I'm wondering is how this will sound compared to the nc400. When is performance so good that it doesn't matter anymore?

www.audiosciencereview.com

 

[thegeton]

No, no reason for you to care at all. But that's because of your particular perspective, approach to amps, and use-case. Many folks, including many members here, view it conversely: why should they pursue a DIY kit if they can get a pre-built unit with a professionally manufactured case, and often a warranty, for the same price?

Neither approach or perspective is wrong; they're just different, and both totally valid.



Welcome to the forum!

You raise a very interesting point, and your point plays into a lot of the discussion here.

The short response to your question is, of course you are correct: the cheapest amplifier that reproduces signals transparently - that is, with frequency response nonlinearities, noise levels, and distortion levels that are below the ability of humans to hear - is by definition the best value.

Of course, in reality it gets more complicated, because there are other questions that are variable based on individual situations and preferences and are sometimes difficult to quantify precisely, but are in my view still within the overall realm of objective qualities of one sort or another:

1. Build quality/likely longevity of the product;

2. Location company and of available vendors - the more inexpensive the product itself, the more the price comparison can change if one item is available domestically with free shipping while another is only available internationally with expensive shipping; and location of manufacturer can also have a major impact on how practical it is to be able to actually take advantage of the warranty if something goes wrong with the amp; and

3. Watts/power/current capacity - do you get an amp with 4x the power for 2x the price of another, otherwise comparable amp? For folks listening in mid-field with highly efficient speakers, the answer is probably No. For folks listening far-field with less-efficient speakers, the answer might be Yes.

Finally, there's the more subjective issue of how a product makes us feel. The science/measurements/engineering ethos of this forum is still an ethos - it still speaks of values that folks bring to their evaluation of products. So having extra power reserves, first-rate build quality, "extra padding" in the performance specs beyond the threshold of audible transparency, and so on - these are things that many folks here like to see in products they consider buying.

Periodically some folks will comment here in threads accusing all of ASR of being a sham or hypocritical because "everyone here chases specs" even when better specs don't make an audible difference, and therefore we are allegedly no different from people who seek out cable lifters, high-end interconnects, and other audiophile "tweaks" even when they don't make an audible difference. The claim is that all this stuff is irrelevant and just makes us feel better, and so therefore measurements are the same thing as snake oil. It's not true of course, but like many bad arguments that refuse to die, it's just close enough to the truth to be misleading.

THIS!

This post is why I'm here.

Thank you.

 

[RandomEar]

I would like everyone here to consider: what are we trying to see here? Considering that music does not have considerable energy in these high frequencies, high power output is never going to be used at high frequencies, except for the possibility that electronic music might have some of this (although no one would ever want to listen to a 15 Khz signal at 100 watts) it would only have this as a test.

Agree.

Additionally, all the harmonics we see here (the distortion products) are well above the audio band, so they are inaudible. I am not sure what the concern here is? If you ask Bruno Putzeys about this behavior as far as the Purifi product goes, I am almost certain he would explain that this behavior is a design choice, that all distortion products are out of the audible range, and that the amplifiers are band limited by design, on purpose, in order to allow for reduced distortion within the audible bandwidth.

This is certainly a design choice and the signals above 20 kHz themselves are inaudible. But - and this is where I would deviate from your reasoning - they would only be inconsequential, if speakers were perfect and would reproduce every signal 100% faithfully. But speakers are not perfect and never will be and from my understanding, it can't be excluded that ultrasonic signals could lead to intermodulation distortion in the speakers themselves and some of that IMD may be in the audible range. The IMD level would, of course, depend on the speaker (mostly tweeter) design. As I said - that is my current understanding, but I'm happy to be corrected in case I am on the wrong track.

Nonetheless, it is clear that even if such IMD signals existed in the reproduced sound, they would be very small in amplitude considering the typically low SPL of real audio in the HF region and the already low-ish level of ultrasonic "dirt" created even when using 0 dB test signals.

There are also quite a few class A/B amplifiers which also exhibit rising distortion with frequency (most of them), go over to stereophile.com and check their measurements of many class A/B amps...
Are we asking these questions just as an engineering exercise? Because, in the real world of listening to music, they are irrelevant to what one will hear.

 

[Rob Fens]

Agree.


This is certainly a design choice and the signals above 20 kHz themselves are inaudible. But - and this is where I would deviate from your reasoning - they would only be inconsequential, if speakers were perfect and would reproduce every signal 100% faithfully. But speakers are not perfect and never will be and from my understanding, it can't be excluded that ultrasonic signals could lead to intermodulation distortion in the speakers themselves and some of that IMD may be in the audible range. The IMD level would, of course, depend on the speaker (mostly tweeter) design. As I said - that is my current understanding, but I'm happy to be corrected in case I am on the wrong track.

Nonetheless, it is clear that even if such IMD signals existed in the reproduced sound, they would be very small in amplitude considering the typically low SPL of real audio in the HF region and the already low-ish level of ultrasonic "dirt" created even when using 0 dB test signals.

Hi RandomEar, Following your reasoning; say an amp distorts harmonically 1% above 20kHz and the loudspeaker has a IMD of 1% also, that would mean (i guess) that there could be a distortion in the audible range of 0.01 (amp 1%) * 0.01 (loudsp 1%) ~ 0.01% which is certainly inaudible. If i am wrong, pls correct.

 

[antcollinet]

Hi RandomEar, Following your reasoning; say an amp distorts harmonically 1% above 20kHz and the loudspeaker has a IMD of 1% also, that would mean (i guess) that there could be a distortion in the audible range of 0.01 (amp 1%) * 0.01 (loudsp 1%) ~ 0.01% which is certainly inaudible. If i am wrong, pls correct.

Both of those 1% are much too high.

We see from the plot that even at 15KHz (first harmonic at 30KHz), distortion is down at -80dB. That is 1% of 1%. Then remember that music content at 15KHz is probably also down 20 to 40 dB at that end of the scale.

Then these tiny signals have to intermodulate back into the audible band in the speaker. You are not wrong - inaudible - even for bats.

 

[Rob Fens]

Both of those 1% are much too high.

We see from the plot that even at 15KHz (first harmonic at 30KHz), distortion is down at -80dB. That is 1% of 1%. Then remember that music content at 15KHz is probably also down 20 to 40 dB at that end of the scale.

Then these tiny signals have to intermodulate back into the audible band in the speaker. You are not wrong - inaudible - even for bats.

Hi Tony, I totally agree with you.

I am not debating the level of distortion of (any) amplifier, but i try to make clear that distortion above 20kHz is unimportant since it is inaudible.

Therefore i do not understand people hammering on distortion above 20kHz.

Maybe they consider a pretty graph to be more important than a good sound.

Maybe it has something to do with the name of this forum, a graph seems scientific and sound seems subjective...

 

[Julf]

Maybe it has something to do with the name of this forum, a graph seems scientific and sound seems subjective...

Understanding of what is audible and what isn't is science too. I think the hammering on about the HF nose is mostly from a couple of anti-Class-D people and has nothing to do with science.