Why NCx500 isn't necessarily an upgrade

[Bjorn]

A 1kHz test is all you need? LOL.

What about low frequencies, intermediate frequencies and high frequencies? 20Hz-20kHz, worst case THD is what I want to see.

And that means an analyzer with a decent bandwidth (~200kHz). Oh, but the NCx needs a filter...

I agree totally, the 1kHz THD+N or SINAD wars are hilariously stupid.

Why the need for a bandwidth that's not audible for humans?

Neverthless, let me know exactly what graphs you want to see.

 

[Mnyb]

How about Nilai ? Any qualms about that one ?

 

[Sokel]

How about Nilai ? Any qualms about that one ?

That's suppose to be for DIYers.
How it ended up in shops is probably another story.

 

[pma]

Voltage noise density related to input is the parameter of interest.

 

[Mnyb]

That's suppose to be for DIYers.
How it ended up in shops is probably another story.

I know but Vera is not operating in the most price sensitiv segment of the HiFi market. Module cost may not be the biggest factor in thier design. I like thier thermal management not many have this .

 

[pma]

Let's look at a THD+N measurement of our Vera Audio P400/1000 with NC500 modules first. Showing both channels in 4 Ohm:

@amirm measurements differ from yours:

Hypex NCx500 Class D Amplifier Review

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. As you see the sample is a "monoblock" configuration (one channel) driven by Hypex SMPS1200 switching power...

www.audiosciencereview.com

https://www.audiosciencereview.com/forum/index.php?attachments/hypex-ncx500-mono-amplifier-oem-class-d-power-4-run-2-measurements-png.257988/

He measures -100dB THD+N at 100mW, which would make 0.001%. Your numbers with NCx500 are several times higher (up to 0.01%).

 

[Hayabusa]

We are in the age of chasing THD numbers in electronics. And while it's certaintly good with low distortion numbers, let me explain why using NCx500 modules or any other newer class D modules isn't necessarily an upgrade. And also why Vera Audio hasn't considered several of new class D modules that been released or are about to be released.

Let's look at a THD+N measurement of our Vera Audio P400/1000 with NC500 modules first. Showing both channels in 4 Ohm:
View attachment 353984

just for fun:

The 0dB SPL line in this graph for a speaker with 90dB/w sensitivity:
( note that 10w is already playing 100dB then )

 

[Bjorn]

@amirm measurements differ from yours:

Hypex NCx500 Class D Amplifier Review

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. As you see the sample is a "monoblock" configuration (one channel) driven by Hypex SMPS1200 switching power...

www.audiosciencereview.com

https://www.audiosciencereview.com/forum/index.php?attachments/hypex-ncx500-mono-amplifier-oem-class-d-power-4-run-2-measurements-png.257988/

He measures -100dB THD+N at 100mW, which would make 0.001%. Your numbers with NCx500 are several times higher (up to 0.01%).

He measured without the internal buffer. From your link:

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

 

[Bjorn]

Here are FFT measurements in differents bandwidths of the Vera Audio P150/600 RS in bridge mode.

20KHz bandwidth:

40KHz bandwidth:

250KHz bandwidth:

 

[Bjorn]

I would say the difference is not in distortion, but in noise. You cannot distinguish it in THD+N plot. You might like to measure THD (without N) as a function of power, instead. REW software (even the free version) will let you find the difference, should it be either THD or N.

My suspect - the gain is the same in both cases??

Is this the type of measurement you're looking for?