Nord MP NC252 SE Amplifier Review

[xanalog]

How can it be a golden sample if it didn’t come direct from Nord?

"Golden sample" for the consumer; probably because it has not been 'tweaked' by the manufacturer!
[aka a production unit.]

 

[Tone]

"Golden sample" for the consumer; probably because it has not been 'tweaked' by the manufacturer!
[aka a production unit.]

Or there is actually a fault other than what we would expect.

 

[Mnyb]

Maybe puritee made a joke conspiracy theorist always elude to "golden samples" if reasonably priced products perform very well in these kind of tests .

In reality the functioning units are so similar due to the way modern electronics are designed so it's no point picking one they perform the same or not at all ? Maybe a function test before it's out for a review ( in case of user sending something it's out manufacturers control ) .

The "golden samples " are in reality this kind off stuff when something is off and not as it should be

 

[Tone]

Maybe puritee made a joke conspiracy theorist always elude to "golden samples" if reasonably priced products perform very well in these kind of tests .

In reality the functioning units are so similar due to the way modern electronics are designed so it's no point picking one they perform the same or not at all ? Maybe a function test before it's out for a review ( in case of user sending something it's out manufacturers control ) .

The "golden samples " are in reality this kind off stuff when something is off and not as it should be

Exactly.

 

[Dmitri]

In my previous post, I used the term “Golden Sample” inappropriately. I would say “Thoroughly vetted” a better description. Though a problem would be unlikely, I’d do the same if it were my product being re-reviewed. No offense intended and no conspiracy theorists need apply. My apologies to “Tone” for inadvertently suggesting Nord would respond with anything less than complete integrity.

The fact that Tone has entered this discussion only confirms Nord’s desire to get to the bottom of the problem.
Kudos.

 

[Hart]

I think the Apollon and others created such a high bar that you really have to compete at that level. The Apollon is a little more money, but with exponentially more power and chart leading specs.

Apollon NCx500ST Stereo Amplifier Review

This is a review and detailed measurements of the Apollon NCx500ST stereo class D amplifier based on Hypex NCOREx NCx500 modules. It was kindly drop shipped from the member and costs 1,090.00€ (US $1,168) with standard opamp. While the case is stamped aluminum, it is a heavily customized one...

www.audiosciencereview.com

 

[Laserjock]

Wondering if a switch bypass could be implemented somehow?
Easy enough for @amirm to try and exercise the switch, if so inclined and not sent back already.

 

[Ropeburn]

I think the Apollon and others created such a high bar that you really have to compete at that level. The Apollon is a little more money, but with exponentially more power and chart leading specs.

Apollon NCx500ST Stereo Amplifier Review

This is a review and detailed measurements of the Apollon NCx500ST stereo class D amplifier based on Hypex NCOREx NCx500 modules. It was kindly drop shipped from the member and costs 1,090.00€ (US $1,168) with standard opamp. While the case is stamped aluminum, it is a heavily customized one...

www.audiosciencereview.com

Hardly comparable. A whole module generation and model up, double the price.

 

[Hart]

Hardly comparable. A whole module generation and model up, double the price.

I think a majority of people putting together a system at a typical "audiophile" level would not quibble over a few hundred dollars.

 

[Ropeburn]

I think a majority of people putting together a system at a typical "audiophile" level would not quibble over a few hundred dollars.

Even if that were true, it still wouldn't change the fact that anything NC252MP simply can't compete with an NCx500 amp. It's a silly comparison.

Also, have you watched the economy? 500 is a lot of money for most people, including audiophiles.

 

[NielsMayer]

It's wired terribly. The output leads are hugely long and act as giant RF antennas within the case. Radiating the switching frequency back into the analog inputs, control circuitry, power supply, etc. For example an unshielded ribbon cable should not be running from the "input amplifier" to the Hypex board -- even if there's a "ground" between each signal wire on the ribbon cable.

Somebody posted a picture of a different amp with the same Hypex module -- which was wired even worse, with even longer output cables that traverse the entire board (which is oriented with the output terminals towards the front while the outputs are on the back).

I'm still very happy with my NC400 monoblocks which seem way better in every way than these OEM boards that require a silly external op-amp based input board -- and long noise-susceptible cabling between the input board and the OEM amplifier -- whereas the right way to do this is with fully discrete, dc-coupled, class-A-biased transistor-based amplifiers and linear regulators all across the board -- at the expense of the thing consuming huge amounts of energy at idle to run all those energy-wasting class-A biased transistors. The last thing i want on such an amp is an op-amp based "input board" to ruin the transient handling with some cockamamie negative feedback circuit and gain-bandwidth-limited-op-amps ringing or rounding transients. An op-amp based input board is not really an "amplifier" it is a differential servo-control circuit with all the time-domain problems that real-world negative feedback induces: https://e2e.ti.com/blogs_/archives/b/thesignal/posts/taming-the-oscillating-op-amp https://e2e.ti.com/blogs_/archives/...late-an-intuitive-look-at-two-frequent-causes

 

[Ropeburn]

Audiophonics MPA-S250NC:

Much better. Note how much power, input and speaker wires are separated. Shows none of these problems and performs as good as any other proper build. Could even be a third smaller and would still be fine.

 

[amirm]

On implementation issue, those would be constant problems, not like this which comes and goes. Company has a theory as to the cause so I am going to test again later tonight.....

 

[Pritaudio]

How about nc122 or nc502 hypex modules.
Any similar known cases or manufacturing processes.

 

[capslock]

The overall layout is unhappy. And why do they use heatsinks with good thermal coefficient if they in fact do not use them for module cooling?? These assemblers without understanding of design principles are strange.

Maybe the have the fins just because they look cooler?

Maybe the case is not high enough to support a module mounted against the heatsink? Maybe the thermal resistance of the case bottom is sufficient?

I will never understand why Topping class B amps (LA90, LA90D, B200) have the fins of their side heatsinks extend horizontally. Have the otherwise excellent engineers never heard of convection? But wait, they were the ones who put opamps and resistors in a potting compound.

 

[amirm]

Company rep suggested to exercise the input selection switch as that has been known to cause problems like this. I am used to this being the case in older audio products, but not new. Still, this amp had been sitting here for a few months and as it happens, I had toggled one of the switches but not the other. Switching back and forth half a dozen times seems to have fixed the problem. Given this, I ran the rest of the tests and updated the review. I updated my recommendation. You may want to do the same with your vote.

 

[GD Fan]

Any chance you can do a tear down?

 

[Mnyb]

Company rep suggested to exercise the input selection switch as that has been known to cause problems like this. I am used to this being the case in older audio products, but not new. Still, this amp had been sitting here for a few months and as it happens, I had toggled one of the switches but not the other. Switching back and forth half a dozen times seems to have fixed the problem. Given this, I ran the rest of the tests and updated the review. I updated my recommendation. You may want to do the same with your vote.

Terrible quality , they need to change the switch to something better, the ones built for audio works fine for decades ? Anyway a good thing that the amp works as it should now

I would not give it excellent due to having such switches, but the next best rating.

Edit I voted Fine

 

[Andreas007]

Why are the switches oxidizing in the first place (especially after such a short time)? Isn‘t this a component design flaw?
Everyone seems happy about root cause found but this does not solve the problem.

 

[pma]

These relays working as input switches for 20+ years without degradation of parameters. More than hundred pieces used.