Hypex NCx500 Class D Amplifier Review

[boXem]

Here’s how the 4ohm buffer-less graph should look.

View attachment 257416

Your measurement?

 

[pma]

That’s why it’s listed below the graph.

Maybe I am blind. What is the measuring bandwidth?? 22Hz - 22kHz, 22Hz - 45kHz, 22Hz - 90kHz?? Thank you. How many harmonics of 6kHz base frequency are included?

 

[Koeitje]

My RME outputs +24dBu, with 12dB gain from the amp that equals ~300W/8Ohms.

Not good enough according to @Willem though. The RME degrades the performance of this amplifier.

4V DACs will drive this amp in its tested configuration (12dB gain) to ca 32W output power.


I am not sure what your point is.

My point is that the way this was tested to not even close to being representative of 99% of real world use cases. Unless you think 32W is an acceptable output level. If that is the case you better off just getting the Topping amplifier...

 

[boXem]

Bandwidth, not frequency.

That’s why it’s listed below the graph.

 

[antcollinet]

Thunder was being sarcastic. Or at least I think he was...

Never seen the film and was unaware of the quote (just had to look it up).

Thunder needed to add a smiley. Poe's law can apply here also

 

[VintageFlanker]

Rouge Audio Design (IT), who did sell OEM amp board from Hypex (and Purifi and Icepower) launghed the N-7X with 2 NCx500 boards for 1385€ excl VAT.

Which makes 1706€, VAT and shipping included to France.

 

[antcollinet]

Harmonics outside of the audible range don’t matter. Which is why the 18+19khz CCIF IMD measurements are what is typically used to measure distortion at the upper range of human hearing. As well as any 2nd order effects that could cause distortion at other frequencies in the audible bandwidth.

True - but we still need to know the measured bandwidth - which has a significant impact on the meaured THD+N Level. If not there is no way to repeat your test.

So if your measured bandwith is 20Hz to 20kHz, fine - but without that defined we can't know how good the result is.

 

[anphex]

What is the cooling limitation? I remember the NC400 only can deliver 400 W a few seconds and then throttles down to 75W. With about 700 W I can only guess this problem will be worse without a cooling system.

 

[Fidji]

And the first finished amps are in store i see, Rouge Audio Design (IT), who did sell OEM amp board from Hypex (and Purifi and Icepower) launghed the N-7X with 2 NCx500 boards for 1385€ excl VAT. They use OPA1612 opamps as buffer and the Hypex HxR discrete voltage regulators and the Hypex SMPS1200A700 PSU. So very stock...

STUDIO N-7x| Rouge Audio Design | Roma

HYPEX NCx500 Hypex Ncore serie X

en.rougeaudiodesign.com

https://en.rougeaudiodesign.com/product-page/studio-n-7x

Audiophonics (FR) is also busy developping their take on it i hear from people close to the guy behind it, and so is Sound Import/SoundImpress (NL) are taking a look at it. So most of the usual suspects in Europe will soon have amps based on this board it seems.

As somebody in the know - any idea whether Audiophonics is working on Purifi 1et7040sa? I asked couple of months ago and the answer was "is in the process"

 

[Hypexsales]

One interesting aspect of the NCx500 is how much light it gives off. The reason for this is twofold:

1. The vertical regulator boards have sets of red LED arrays that light up as an H.
2. A bright white LED (seen below on the middle right edge of the board).

View attachment 257309

Do these serve any function? The data sheet does not indicate. The NC1200 has comparable regulator LEDs. The white one is close to a thermal sensor, so my best guess is it may indicate thermal overload.

Hi Rick,
I can clearify the LED functions. The red LED's on the 12V regulators are not for show, yes we could arrange them like an H from Hypex but that is just coincidence. we use LED's because they have much lower noise compared to Zener diodes and are temperature independant.

The white LED on the module itself is an indication for all errors, not only temperature. Steady on is the normal status.

 

[xaxxon]

Yes it’s 20-20kHz. Any wider bandwidth would provide misleading results. Which is why professionals do the 18+19khz CCIF IMD test.

what does bandwidth mean in this context? I get that you're intending to send a specific frequency to the amp... is bandwidth the area you're looking for noise?

Links are great, too

Thanks.

 

[restorer-john]

Yes it’s 20-20kHz. Any wider bandwidth would provide misleading results. Which is why professionals do the 18+19khz CCIF IMD test.

No. A wider bandwidth would actually capture all the harmonics and measure them, just as amplifier measuring has done for the last 70 years. 10th harmonic or 200kHz has been the standard forever.

Now, with so much bandwidth-challenged class D gear, which is also full of HF noise, the rules needed to be changed to accommodate their deficiencies. Don't pretend it is anything else.

But it is what it is and I don't lose any sleep over it. But I'm not so naïve as to read any class d 'datasheet' as anything other than painting their product in the best light possible for the ignorant, and glossing over the deficiencies. Seems to be the standard MO for Hypex and others since day one.

 

[xaxxon]

edit: Never mind review got updated to include buffer - still looks good.

 

[restorer-john]

is bandwidth the area you're looking for noise?

That is correct. 20-20kHz, UNWTD, or DC-200kHz A-WTD etc.

The wider the bandwidth, the more the noise. Even using the 20kHz as opposed to the 22kHz filter will gain a dB or 2.

 

[antcollinet]

83% of people gave this a golfing panther when it's super hard to get the wattage out of it... that's confusing to me.

I'm excited to see what this module can do in an amp with a good buffer stage and may buy one if it still looks this good, but I wouldn't want the amp configuration as tested.

The tests have been updated with 27dB gain buffer enabled.

 

[xaxxon]

The tests have been updated with 27dB gain buffer enabled.

just when I thought I'd get to fall asleep...

Thanks.

 

[JSmith]

Here’s how the 4ohm buffer-less graph should look.

View attachment 257416

I recognize the font at the bottom... is that from an internal Hypex datasheet?

... looks the same as this published at Audioxpress, however I see no info about this being "buffer-less"?

Hypex NCOREx THD vs Power 1kHz-6kHz @4 Ohm.

Hypex Announces New and Improved NCOREx Class-D Amplifier Technology

Hypex Electronics announced a new and improved iteration of its popular NCORE Class-D amplifier technology and unveiled the NCx500 OEM, the first of a new NCOREx family of modules to be launched. According to the Dutch company, the new technology will afford at least 2x better performance...

audioxpress.com

JSmith

 

[DrCWO]

@amirm,
would you please be so kind and give us the THD+N chart of NCx500 in comparison to AHB2 in bridged mode. Comparing both we should see the same power delivery but the different distortion figures.

Having both in one chart we will have the same scale as in your review of the AHB2 you did not use the dB scale.

I think it will be quite interesting to see how much less distortion the AHB2 has at higher power levels.
Thanks DrCWO

 

[antcollinet]

No the measurements have adapted to provide information that’s actually useful.

Hi @Classdampman - a belated welcome to the forum.

Are you associated with Hypex by any chance - Fantastic if so - it is always good to get input from people with detailed knowledge of the kit we are discussing. But just as a heads up, it is requested by forum admin that you get a "manufacturer" stamp for your account.

Please see:

Rules for Audio Dealers, Manufacturers, Members with Commercial Interest. This includes any Guest Contributors/Reviewer with Commercial endorsement

We have been operating without specific guidelines for members of the industry and this has caused a number of issues/complaints. So I thought it is time that we set some rules: Audio Science Review Rules for Dealers, Manufacturers, Reviewers and Members of Industry. We encourage...

www.audiosciencereview.com

To be fair - this post is not easy to find.

 

[antcollinet]

Thanks. No I’m not associated with Hypex. I believe Hypex has their own account here already.

Fair enough - you appeared to be particularly knowledgable about the amp tested here, and also seemed to be defending it - hence my assumption.