Nord MP NC252 SE Amplifier Review

[YSDR]

From Apollon amigos :

"Most of the failed modules we’ve encountered were from the first revisions of the NC252MP, specifically those manufactured between 2017 and 2020. A significant number of these failures occurred in systems that were driven hard, even with forced fan cooling, which clearly shows that airflow alone wasn’t the issue."

A have a pair of this earlier NC252MP and they not even had with low-ESR electrolytic capacitors at all, which otherwise would be a mandatory for switching amps and SMPSs for good functioning. I replaced all the elcos with low-ESR types and the heat generation of the whole amp reduced significantly.

Newer NC252MPs have low-ESR caps in some places, which is better than nothing but still far from optimal.

 

[daniboun]

A have a pair of this earlier NC252MP and they not even had with low-ESR electrolytic capacitors at all, which otherwise would be a mandatory for switching amps and SMPSs for good functioning. I replaced all the elcos with low-ESR types and the heat generation of the whole amp reduced significantly.

Newer NC252MPs have low-ESR caps in some places, which is better than nothing but still far from optimal.

What would be interesting is to know if the observed defect has indeed been corrected on the latest NcX252MP models.

 

[YSDR]

What would be interesting is to know if the observed defect has indeed been corrected on the latest NcX252MP models.
View attachment 497881

It seems these new NCx-MP boards uses Aishi RS (low-ESR, high ripple current, long-life type) series capacitors in the critical places, wich is a good sign for reliability. Although still not NCx500 or Nilai level (which uses japanese Nichicon and/or Rubycon capacitors).

 

[Tone]

Still here!

I take on board the use of ribbon cable for analogue signals and I mentioned this to Amir in pm during investigation:

"I've never been completely comfortable with using unshielded ribbon type signal cable, as invited by the module design having this type of socket fitted"

The fact that this was exacerbated by the coupling effect from the other control cable is our oversight at these levels of technical measurement even if the audio performance is unaffected by any usual listening.

Any existing customers will be looked after, that goes without saying.


Hypex themselves, and Purifi for that matter, still use or suggest the use of, ribbon cables for audio signals on certain products.

But in any case my job is to take the criticisms, filter out the sensationalism, and offer sensible solutions without excuses.

 

[Matias]

That is why the good practice is to route the cables around the board, and avoid overlap, such as done by a competitor below (in this case a NC502MP module but the same logic applies). Also shielded input cables into the connector.

 

[YSDR]

That is why the good practice is to route the cables around the board, and avoid overlap

Moreover as we can see, the input connection can be done without that dreaded ribbon cable.

 

[Tone]

Also shielded input cables into the connector.

View attachment 497907

Is it shielded?
But yes, kept away from noise pick up.
Point taken.

 

[Tone]

I see it written on the cable now. Floating shield or connected at input socket end, either way.

 

[CountZodiac]

The images so far have been the 'SE' model, here is a recently built (October 2025) standard cased model. Due to the different rear panel layout the wiring is a little different and all looks good to my untrained eye.

Nord One MP NC252

​

 

[kyuu]

I'm not understanding the rationale to use a ribbon cable for this purpose. For digital connections inside a computer, sure they're fine. But why in the world would you use them for analog connections in an amp? It's been known for a long time that this not an appropriate use. From Wikipedia:

Interference​

From a digital point of view, ribbon cable was an ideal way to connect two devices. However, from an analog point of view, these cables are problematic. Around 1980, the U.S. Federal Communications Commission (FCC) discovered that ribbon cables were highly efficient antennas, broadcasting essentially random signals, or Electromagnetic interference, across a wide band of the electromagnetic spectrum. These unintended signals could interfere with domestic TV reception, putting snow on the screen. The FCC issued edicts and injunctions to the personal-computer industry, restricting the use of ribbon cables to connect devices together. Naked ribbon cable could be used inside the case of a computer or peripheral device, but any ribbon cable connecting two boxes together had to be grounded. This rule led to solutions such as ribbon cables covered by a copper-braid shield, which made it impossible to see or separate the individual connectors. On the Apple II, these cables passed through the holes on the back of the computer that were grounded to the power supply. Eventually, ribbon connectors were replaced, for interconnect purposes, by a wide profusion of custom-designed round cables with molded connectors.

 

[Tone]

Seen attached is Hypex cable set including a 16 way ribbon cable for audio input.

Again, just saying.

 

[Tone]

I'm not understanding the rationale to use a ribbon cable for this purpose. For digital connections inside a computer, sure they're fine. But why in the world would you use them for analog connections in an amp? It's been known for a long time that this not an appropriate use. From Wikipedia:

"Naked ribbon cable could be used inside the case of a computer or peripheral device, but any ribbon cable connecting two boxes together had to be grounded."

Let's not get into sensationalism here.

 

[kyuu]

"Naked ribbon cable could be used inside the case of a computer or peripheral device, but any ribbon cable connecting two boxes together had to be grounded."

Let's not get into sensationalism here.

Let's not take things out of context here. The context for that quoted section was to prevent the radiated EMF from a ribbon cable affecting external devices. In the case of the amp, there are unshielded analog components inside the case to be affected. Also, an antenna works both ways, so the cable will also be good at picking up any stray EMF from nearby components. IOW, it's simply not a suitable interconnect for the application.

 

[Tone]

IOW, it's simply not a suitable interconnect for the application.

For precisely what application, kyuu?

The quote from Wikipedia is about connection between devices.

Internal analogue signals can be connected by 'unshielded' copper, most pcbs are as such.

What's to be observed is that this does not pick up interference in any significant way.

Belt and braces, always use shielded cable and route away from sources of interference.

Can I get my coat now?

Jk.

 

[Sokel]

Sane routing practices apply just fine to any case.
But at the same time I'm afraid that to optimize it to the best it can be is a trial and error procedure to each one of them.
Take two identical ones and they might not behave the same.

But, again, in general, not mixing/routing together/ etc small and big signals, mains, control, etc is the very least. Hard to do sometimes, by design alone admittedly.

 

[Tone]

Sane routing practices

Made me smile.

 

[Tone]

Take two identical ones and they might not behave the same.

Then they are not identical by definition.

Off topic.

 

[Totoro]

I actually really like that term, 'technocratic', can be be too technical?

I can joke too, just not that good at it.

 

[amirm]

I'm not understanding the rationale to use a ribbon cable for this purpose.

It is due to the way the module is designed with a female ribbon cable connector for I/O. This is why I said it is a design issue for the module. It is as if a digital designer thought of that instead of analog. Shoehorning twisted/shieled cables into that connector requires custom assembly and higher costs than needs be.

 

[pma]

Shoehorning twisted/shieled cables into that connector requires custom assembly and higher costs than needs be.

Or better layout planning.
The position of input module and speaker conns should have been swapped on the rear panel. Then, together with indicated longer power switch cable run, the EM field induction would have been almost eliminated.