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Hypex NCx500 Class D Amplifier Review

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 3 0.7%
  • 2. Not terrible (postman panther)

    Votes: 6 1.3%
  • 3. Fine (happy panther)

    Votes: 55 12.0%
  • 4. Great (golfing panther)

    Votes: 394 86.0%

  • Total voters
    458

amirm

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This is a review and detailed measurements of the Hypex NCx500 NCOREx reference design amplifier. It was sent by the company and kindly assembled by our local expert, @Rick Sykora.
Hypex NCx500 Mono amplifier OEM Class Review Board.jpg

As you see the sample is a "monoblock" configuration (one channel) driven by Hypex SMPS1200 switching power supply. The only other board is the Ncore standard interface board. The gain as set is almost 12 dB. EDIT: see follow up below review for with buffer (27 dB gain) performance.

Here is a close up:
Hypex NCx500 Mono amplifier OEM Class Review Bare Board.jpg


Note that this board includes a pre-amp (buffer). I am testing per above in unbuffered mode.

During use the amplifier as a whole was extremely stable and never changed its temperature, nor did it go into protection mode. A sole XLR connection is the input to the unit. All fits in this nice compact box.

Hypex NCx500 Buffer Bypass Amplifier Measurements
I let the unit warm up for a while but was not needed as it was stable as soon as powered up:
Hypex NCx500 Mono amplifier OEM Class D Warm up Measurements.png


It did reach a plateau around 11 minutes though as you see. But note that the vertical scale is 0.1 dB.

Now on to our dashboard of 1 kHz tone at 5 watts into 4 ohm load:
Hypex NCx500 Mono amplifier OEM Class D Measurements.png


Distortion is provably inaudible at -120 dB. A bit of noise sags that down to 113 dB which is still superb performance, landing it at #2 best amplifier every tested:
Best class D monobloc amplifier review 2023.png

Noise performance is exceptional:
Hypex NCx500 Mono amplifier OEM Class D SNR Measurements.png


Even when listening to 16 bit content at 5 watts, you have an extra 10 dB of noise margin! This is one quiet amplifier.

Frequency response is wide and load invariant which is a great attribute not existing in all class D designs:

Hypex NCx500 Mono amplifier OEM Class D Frequency response Measurements.png


Multitone test shows off its low distortion yet again:
Hypex NCx500 Mono amplifier OEM Class D Multitone Measurements.png


I must say, I was not prepared for the amp to beat the reference Benchmark AHB2 in noise level in our power test:

EDIT: I re-ran the power sweeps again with tighter load terminals which resulted in much lower distortion levels especially at 4 ohm:
Hypex NCx500 Mono amplifier OEM Class D Power 4 Run 2 Measurements.png

Despite massive amount of power the NCx500 produces, its distortion is now close to the best we have ever measured!

I updated these max and peak measurements again which produced more power:
Hypex NCx500 Mono amplifier OEM Class D Max and Peak Power 4 Measurements.png


Company specs this power level even at 2 ohm so I tested that:
Hypex NCx500 Mono amplifier OEM Class D Max and Peak Power 2 Measurements.png


This is one powerful amplifier!

Here is our updated 8 ohm power:
Hypex NCx500 Mono amplifier OEM Class D Power 8 Run 2 Measurements.png


I was surprised how much lower its noise level is compared to Purifi 1ET400A reference design. Maybe that amp was not running at such a low gain setting though (edit: correct). Still, this is once again superb performance.

Sweeping with different frequencies we see various distortion mechanisms kicking in (edit: now updated showing much less distortion):
Hypex NCx500 Mono amplifier OEM Class D Power 4 vs frequency Measurements.png


There is some rise in distortion with frequency but this is to be expected.

Finally, here is the pop on and off noises. Keep in mind that this is a reference design and the on/off switch turns the whole unit on and on as opposed to soft power:

Hypex NCx500 Mono amplifier OEM Class D Power On off Pop noise Measurements.png


Hypex NCx500 Buffered Measurements
As noted, there is integrated buffer (pre-amp) in this module. I activated it which boosted the gain to 27 dB. Maximum power is now achieved at around 2.2 volts which is well within the output of many well designed DACs using balanced out. Here is our new dashboard:
Hypex NCx500 Mono amplifier OEM Class D Measurements.png


Distortion has gone down a bit but we have picked up a bit of power supply noise. Despite that hit, performance is still state of the art:
Best class D amplifier.png


Best class D zoomed amplifier.png


As noted, SNR has gone down but still excellent:
Hypex NCx500 Mono amplifier OEM Class D SNR Measurements.png


Multitone is mostly the same but impacted by the power supply noise:
Hypex NCx500 Mono amplifier OEM Class D Multitone Measurements.png


Frequency response is the same:
Hypex NCx500 Mono amplifier OEM Class D Frequency Response Measurements.png


As noted distortion is lower:
Hypex NCx500 Mono amplifier OEM Class D Power 4 Measurements.png

Hypex NCx500 Mono amplifier OEM Class D Power 8 Measurements.png

Hypex NCx500 Mono amplifier OEM Class D Power 4 vs frequency Wioth Buffer Measurements.png


On/Off noise is impacted a bit:
Hypex NCx500 Mono amplifier OEM Class D With Buffer On Off Noise Pop Measurements.png


Conclusions
Hypex amplifiers have always enjoyed great performance in our testing. It is wonderful to see the company innovating and increasing the performance of their high power NC500 platform. You no longer have to compromise between available power and superb technical performance. You can have both.

It is my pleasure to recommend the Hypex NCx500 OEM amplifier module. Cant' wait to see it show up in commercial designs.

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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 
Last edited:

JSmith

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Well this is excellent and nice to see the results. Also an interesting comparison to Purifi based amps. Thanks @Rick Sykora for building/sending in and @amirm.
Makes me proud of my home town Groningen where the company produces.great stuff!
Indeed and a lovely town to visit too, very picturesque.


JSmith
 

Marc v E

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Basically imo in this design the apprentice betters the master. I'm curious what makes this design lower in noise than the purifi, which according to its maker is mathematically perfect.

My uneducated guess is that the design goals are different resulting in different measurement results.
 

GXAlan

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Waxx

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You see the signature of Bruno Putzeys (the developer of the original NCore) in it. I don't know if he still was direct involved but the resemblence with the Purifi modules is striking...

Purifi 1ET400A (left) vs Hypex NC500x (right)
1ET400A-75deg-full-res.png
20220510205515_2022-05-10_Hypex-NCOREx_02_(1200x900).jpg


But it surely is a great clean amp. And the original NCore was already great (and the first class D amp that did not disturb me in a hifi setting). I may be known as someone who like coloured gear (and that is), but i do also enjoy these kind of clean amps on the right speaker set. I even own a NCore based amp.
 

Rja4000

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Thanks again for this interesting product's review!

Nice to see such good and powerful amp.

Stupid question:
I guess the noise performance is partly due to very low gain.
So, probably, with the buffer, noise will be higher.
But can the buffer help with the distortion ?
I doubt so, but a quick comparison at same output power would give us a clue.

Also:
Even when listening to 16 bit content at 5 watts, you have an extra 10 dB of noise margin!
I read 116dB SNR, so rather 20dB margin, if I'm not mistaken ?
 

BossBunos

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Very nice amp and review!
I thought all amps were sinad ranked with the same gain (4v max power?). The benchmark in low gain also performed 'better". It's a bit like cheating the ranking imo. Like suggested before, a dashboard (and that sinad rating) at normal gain would be a nice addition.
 
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