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Review and Measurements of Hypex NC400 DIY Amp

maty

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maty

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Bel Canto Design -- Bel Canto Black ACI 600 Internal Technology



They seem the NC500. But the graphs are very different! And the values.


Marantz, THD 0.1% and 8 Ohms: about 160 watts

Marantz, THD 0.1% and 4 Ohms: about 290 watts


Bel Canto, THD 0.1% and 8 Ohms: about 290 watts

Bel Canto, THD 0.1% and 4 Ohms: about 300 watts


Maybe the key, with power at 8 Ohms, is a different PSU (s).

Marantz has this little SMPS. Hypex with heatsinks over the big caps 105º <- heat is a problem in SMPS.

 
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maty

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Marantz: one small SMPS for two NC500 modules is a very bad election. And more if we talk about €4000 or $4000 !!!



Btw, I can see two white ferrites.
 

maty

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For me it is a clear bet for the cost reduction where it should not. At least have placed one SMPS1200 (with additional heatsinks over the big caps 105ºC, a good idea -I take note). Of course, better with two as Apollon, Nord, Rogue Studio and others.

I have the AV Marantz SR4500 (2004-2005) in my second system (with KEF Q100 speakers). It suffers from cost reduction where it should not but it is easily solvable by spending very little money. After which the sound is much better than when it came to me. Modern AVR have much worse specs.

Talking about my Marantz: https://www.soundandvision.com/content/marantz-sr4500-av-receiver-ht-labs-measures



[ This graph shows that the SR4500's left channel, from CD input to speaker output with two channels driving 8-ohm loads, reaches 0.1% distortion at 100.4 watts and 1% distortion at 114.6 watts. Into 4 ohms, the amplifier reaches 0.1% distortion at 128.2 watts and 1% distortion at 158.8 watts. ]

THD is lower than 0.02% with power < 85 watts (8 Ohms), with two channels on.


Bel Canto ACI 600



Fig.7 Bel Canto Black ACI 600, analog input, distortion (%) vs 1kHz continuous output power into 8 ohms.
 
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Bel Canto, Marantz, et al. have probably followed Hypex's advice about tuning a "brand sound" into the input stages.

After checking the Polish Marantz measurements more closely, I'm pretty sure they do not include an HF filter. Compare figures 2 & 3.
 

D700

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So perhaps Marantz is just under powering the NC modules as a design choice? Have to assume they know what they're doing and measure their own gear. The knee in the curve is still well under .1, so presumably beyond even dog ears inaudible, no? Car, computer, phone manufacturers do this all the time for various reasons (space constraints, fit a market niche, keep it cool inside). I'm looking forward to amirm's review of the HD-AMP1.
 
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The Bel Canto is an integrated amplifier, so the noise levels aren't necessarily representative of the nCore modules. There are actually a ton of measurements out there for a variety of nCore products ranging from NAD, to Theta Digital, to ATI. The distortion signatures into higher powers and at higher frequencies are all fairly similar.
NAD: https://www.stereophile.com/content/nad-masters-series-m22-power-amplifier-measurements
Bel Canto: https://www.stereophile.com/content/bel-canto-eone-ref600m-power-amplifier-measurements
Theta Digital: https://www.stereophile.com/content/theta-digital-prometheus-monoblock-power-amplifier-measurements
ATI: https://www.soundandvision.com/content/ati-at527nc-and-at524nc-amplifiers-review-test-bench
Wadia: https://www.soundstagenetwork.com/i...dia-a315-stereo-amplifier&catid=97&Itemid=154
Bel Canto: https://www.soundstagenetwork.com/i...rs&catid=97:amplifier-measurements&Itemid=154
Mola Mola: https://www.soundstage.com/index.ph...la-kaluga-mono-amplifiers&catid=97&Itemid=154

That should keep you busy for awhile. :) The Mola Mola should be basically a textbook implementation since the nCore designer owns that company. Suffice to say that whenever anyone measures these things, the high frequency distortion figures don't seem to live up to the datasheet, which substitutes IMD measurements above 6kHz. That may or may not be a valid way of doing things. I tend to think it's not, since they do just "okay"
on the 19kHz+20kHz IMD test. Certainly no better than a well-engineered AB design. I would probably want to run one through a lot of multitone IMD testing to see how well they actually perform. In all fairness, the designer has previously stated that his goal was just to make Class D work as well as a typical class AB amp. He did that, and then some.
 
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maty

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Presumably, they knew what they were doing. That is why I could not believe it, especially in such an expensive product.

I find incomprehensible such a terrible decision, something must be wrong in the company. In other words, the designers / engineers must lack any decision capacity.

They boast copper and more copper and then save on such an inadequate power supply. Surely they detected that it got too hot, hence the heatsinks.
 

maty

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Although KI Ruby's design does not change much, special details appear. Certificate, exceptionally significant serial numbers, above the Marantz logo - Ken Ishiwata's laser-cut signature, and a small emblem in "ruby" colors and shapes nearby.
Btw, what Ken Ishiwata should think about it? :(
 

Ron Texas

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Certainly no better than a well-engineered AB design. I would probably want to run one through a lot of multitone IMD testing to see how well they actually perform. In all fairness, the designer has previously stated that his goal was just to make Class D work as well as a class AB amp and for a Class D amplifier, they are quite spectacular.
For the typical home user whether it's Class D or Class AB, it doesn't make much difference. What I think we want is lots of power with low distortion for a reasonable price, which probably means under $1,000. My Crown XLS 1502 has power, a low price, measures marginally and sounds good. I suspect younger listeners could hear the difference between it and this NC400. It will likely last longer.

What I have found with Hypex amps is many will require a preamp. Nord tells me 2.35 V to reach 200 Watts @ 8 ohms with an MP 252 module. The power supplies don't seem to be built with longevity in mind. The ones with attractive pricing have to be shipped to the US from England or the UK. I suspect somewhere there is an easily available, probably integrated unit from Japan that does the trick.
 

DonH56

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I think ATI (NCore, not HYpex, IIRC) and perhaps others have built class-D amplifiers using large conventional linear supplies. Since supply modulation can directly affect the output, subject to feedback (much better now than 10-20 years ago for class D amplifiers), I wonder if there's a market for that? (I could get rich in the 0.001% of the week I actually have free, eh? :) ) Ideally a SMPS is a much better choice but I wonder about reliability given comments here... For low-voltage use the SMPS used at work are very reliable, millions delivering 10~20 A at 1 V and 1.8 V in crowded high-temp/high-noise environments for years, and certainly wall warts seem to work OK as well as the +/-15 V etc. supplies for low-level gear, but I wonder if the high-voltage versions for audio amps are having growing problems? What is inside the Crown, maybe they and some of the other pro guys have it figured out after doing for many years whilst Hypex etc. are still learning? Or learning what corners can and cannot be cut (Google "Muntzing", R.I.P. Earl)... High voltage, high current, and high-slew(*) have always been a challenge.

Curious - Don

(*) Note that, unlike the discussion of the slew rate needed for audio signals, much higher slew rates are needed in class D switching outputs and SMPS (switch-mode power supplies). Switching rates can be in the MHz (though probably not for power amps) and the longer it takes to slew the lower the efficiency and the greater the heat in the output devices.
 

maty

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Off topic

Young and not young people listen to very bad recorded music with low or very low DR (dynamic range). With voices with autotune (vade retro satana) and electronic or soft instruments. It is not necessary to spend a lot of money on the music equipment, and it is even counterproductive.

With the Crown XLS 1502 they will be very happy I think.

But if you listen to very good recordings with high/very high DR, acoustic instruments and natural voices (without autone)... then you need a good system, that measure well, to have a good electrical grid and go eliminating one by one the usual bottlenecks.

To be properly informed takes a lot of time, patience, intellectual effort... something that today is incapable the vast majority, accustomed to immediate satisfaction. And they believe that any problem is solved by spending and spending the money, very common disease in the audiophile world.
 

Ron Texas

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Young and not young people listen to very bad recorded music with low or very low DR (dynamic range). With voices with autotune (vade retro satana) and electronic or soft instruments. It is not necessary to spend a lot of money on the music equipment, and it is even counterproductive.

With the Crown XLS 1502 they will be very happy I think.

But if you listen to very good recordings with high/very high DR, acoustic instruments and natural voices (without autone)... then you need a good system, that measure well, to have a good electrical grid and go eliminating one by one the usual bottlenecks.

To be properly informed takes a lot of time, patience, intellectual effort... something that today is incapable the vast majority, accustomed to immediate satisfaction. And they believe that any problem is solved by spending and spending the money, very common disease in the audiophile world.
Not as far off as you think. Not young by a long shot here. Reading the XLS 1502 review while I was away from home did kind of knock me for a loop, but when I got home it sounded really good. Being able to roll off the LS50's @ 80 hz and not needing a preamp to deal with low sensitivity of many of these Hypex amps are benefits. One can actually see long excursions go away in that 5.25" LF driver. (It's really a midrange with a more compliant suspension.)

You touch on a very important topic. That is, what is this hobby all about and what do we mean by high fidelity. For some it certainly is buying expensive, impressive looking gear. Around here we have some technically knowledgeable people who do amazing things with measurements and room EQ. I just love music, mostly listen to decent recordings and don't want the gear to get in the way.
 

PierreV

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On the topic of Hypex's power supply's reliability, am I correct assuming on power supply per amp (as in dual mono configs) would be less stressed?

I went to Hypex's site yesterday (yeah, I am supposed to save money reading this site, somehow the opposite happens ;) ) and wanted to order a kit and noticed their web store only has the mono kit these days it seems.

Thanks for the Marantz internal pics Maty! I also own a HD-AMP1 and, while it is an sweet sounding amplifier, there are some things I don't like about it: it does go in "protection" mode very quickly, with the power barely half way. That paranoid protection could be a sign of a stressed design. I opened the case, but decided against disassembling the device further when I saw how one did not have even visual access to anything without many additional steps.
 

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