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Reliability of Hypex modules - Early failure of NC252MP module

suttondesign

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I use Nord-assembled 4-channel amps for my main system, which requires 8 channels for a pair of Linkwitz LX521.4. I bought the first of these two amps in Jan. 2020 for a pair of LXmini. They use the OEM NC252MP modules from Hypex.

One 2-channel module within that amp has now failed. The other works fine, so it's not a Nord problem, but a module problem. I don't recall having any amp fail since I started buying separates in the 1980's (various yamaha, adcom, ATI, museatex (obscure, I know), Meridian, Parasound), though some have been noticeably better than the others as far as noise goes. To have an amp module fail less than 2 years out is disheartening. I don't worry about the warranty issue, and in fact I don't mind installing a replacement module myself instead of shipping the whole amp back to England for Nord to do it, but this does worry me about these convenient, high-performing class-D modules generally.

ps
 

tw99

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It could potentially be a Nord problem if their mechanical design isn't providing enough cooling, for example.
 

JSmith

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NC252MP modules from Hypex
... don't use the best quality capacitors and nor do Purifi. One amp supplier offers to change these for higher quality caps that have a longer rating.

2 years is much too short a time though, even if it was on 24/7. Even though you say it doesn't get more than warm, the early failure suggests the caps were running close to the rated temp and so failed prematurely.

Have you contacted Nord yet about this failure?



JSmith
 

Chrispy

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With new technology somebody has to be the guinea pig to an extent.....but hopefully this failure was limited to the amp itself? Didn't take anything else out with it? Can be repaired by a simple modular replacement?
 
OP
S

suttondesign

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Nothing else seems to have gone down. I tested the (super nice) lower-mid drivers with a 9v battery, and they seem fine mechanically, though I can't guarantee it until I run them full-range again.

I am speaking with Nord about the problem. To make sure I was right about the point of failure, I rigged up a test setup with an old iPod directly feeding the unbalanced inputs for the failed channels, then ran a short length of speaker wire to a spare raw driver. Dead. Doing the same test setup to Chs 1-2 produced sound. Seems clear it's just the one of the two modules. It looks extremely easy to swap it out, some screws and some plug-in wire harnesses.
 

MakeMineVinyl

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I think this can be considered a random failure which is probably rare. There are several things which can go wrong in the manufacture of a PCB, and a defective part is not unheard of, but I wouldn't get overly alarmed by this particular failure. If you have another, then that could be a trend which would merit increased concern. As with all electronics, make sure that they are operated in a space where there is adequate airflow so heat doesn't build up.
 

Phorize

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I’m not aware of wide reports of hypex module failures. There are vast numbers of them out there. Sounds like you’ve just been unlucky. If it’s in warranty Nord shouldn’t mind replacing the module.
 

Phorize

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... don't use the best quality capacitors and nor do Purifi. One amp supplier offers to change these for higher quality caps that have a longer rating.

2 years is much too short a time though, even if it was on 24/7. Even though you say it doesn't get more than warm, the early failure suggests the caps were running close to the rated temp and so failed prematurely.

Have you contacted Nord yet about this failure?



JSmith
I was under the impression that the Rubycon caps in the purifi modules were quite good.
 

Snarfie

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About 35 years.;)

Found this detailed answer from @restorer-john about the difference between Class D amp's an the older Amp's.


What‘s the difference between NAD 2200 and NAD M22/M22.2 35 years. :)

Topology is completely different. The M22 is Hypex OEM NC400 Class D. The 2200 is a commutating rail through-hole dinosaur from the mid 1980s, but, as you can see, not only is it still working, it's repairable and not too bad looking for a NAD, and it still performs very well.

There's no way on earth the SMPS powered M22 will last 35 years. It's chock full of microcontrollers and SMD lead-free componentry. But, it is new and some people want that. I get it.

Again, it's a tough call. You either find a classic monster power amp from the past and throw some restoration dollars at it (not just some capacitor-jockey with a bag of parts and a plumber's soldering iron) and it will last another 35 years, or you get a shiny new modern amplifier and expect 5-10 years before total replacement. All we can hope is the tougher (!) new European regulations on repair-ability and parts will improve the situation which has been going downhill for decades.

I'd like to see young restorers down the track, still able to get parts and keeping some of these wonderful products from the past alive. I'll gladly donate all my parts and gear to some young whipper snapper when I can no longer read resistor color codes or my hand is too trembling to solder. Hopefully that is decades away...

Part 2.

The NAD M-22 is full of microcontrollers. There's three of them! Yes, in a two channel power amplifier...

One in each NC-400 OEM module. (PIC16F690) x2. (the 20 pin IC I have circled)
And another (PIC18F26K20) for general housekeeping. (on NAD's MCU board)




index.php



NC-400 OEM:

index.php



NAD M22 block. One channel shown.



index.php



PICs are fragile. Their A/D lines are easily damaged and when they fail, you are screwed basically. Code is protected, so they can't be cloned, even from another functioning controller. You can buy a PIC16F690 for a dollar or two, but you can't load Hypex code into the EEPROM. Will they sell you a coded micro? Nope. What hope do you have in 20 years when Hypex is long gone? Answer: E-Waste.

Wherever you have high voltages and high currents (in power amplifiers) things go wrong now and then, and little micro-controllers are often the first to go. Let's see if the EU regulations force companies like Hypex and others to release source code (or set the code protection flag to 0) so people can legitimately repair their gear. I won't be holding my breath.

Anyway, as for the wait and see approach, we all know that simply is doomed to fail. The NAD 2200 is 35 years old and has proven itself. It didn't need no stinkin' microcontrollers back then to achieve state of the art performance and doesn't need them now.
 
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Kegemusha

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Sadly sometimes in electronic devices, things can fail quickly, it should not, but happens.
I hope Nord can send you a module and you can just replace it.

I will not argue about the NAD 2200, is a great amp, if I would have that one, I will never change it.
 

JSmith

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I was under the impression that the Rubycon caps in the purifi modules were quite good.
NAD replace them with United-Chemi-Con which is fine and Apollon Audio also offer a cap replacement on both NCore and Purifi amp modules. The standard ones used are supposedly rated at 5000 hours (at max temp) and the replacements are 20000 hours.

https://www.audiosciencereview.com/...28-7-channel-purifi-amplifier-teardown.15981/
The capacitors have been replaced from Rubycon in the original reference design to United-Chemi-Con...

https://www.audiosciencereview.com/...integrated-amplifier.20426/page-8#post-693708



JSmith
 

Snarfie

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Sadly sometimes in electronic devices, things can fail quickly, it should not, but happens.
I hope Nord can send you a module and you can just replace it.

I will not argue about the NAD 2200, is a great amp, if I would have that one, I will never change it.

I had some issues with my NAD C370 protection circuit so i was thinking buying a class D amp which sounded great but not better than the C370. I decided after reading here on ASR to repair the circuit An some other capasitors set me back less than 75,- euro including labour cost. Starts again fast An works like a charm
 
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Phorize

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NAD replace them with United-Chemi-Con which is fine and Apollon Audio also offer a cap replacement on both NCore and Purifi amp modules. The standard ones used are supposedly rated at 5000 hours (at max temp) and the replacements are 20000 hours.

https://www.audiosciencereview.com/...28-7-channel-purifi-amplifier-teardown.15981/


https://www.audiosciencereview.com/...integrated-amplifier.20426/page-8#post-693708



JSmith
That sounds good, but if I’m running my purifi amps output an average of 20 odd watts, that’s power consumption of no more than 40 odd watts, and the thing is almost cold.

Contrast the admittedly awesome Denon a110 which is consuming 400 watts and pushing out lots of heat. I’d expect the purifi caps to last a lot more than 5000 hours, and by the time a recap was needed I would have saved enough electricity to buy a new amp. ;)
 

ebslo

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I don't think one sample, or 10 for that matter, is sufficient to draw any statistically sound conclusions.
Especially when comparing with 35 years of survivorship bias.
 

DWPress

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I will not argue about the NAD 2200, is a great amp, if I would have that one, I will never change it.

Well, I've got 3 NAD 2200s sitting in storage (each with issues) and I've replaced them with Ncore modules. I always enjoyed the NADs but don't miss the heat and power use. Should probably pass the 2200s along to someone with a restoration urge.
 

daftcombo

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Perhaps we could open a thread here linking to an Excel sheet where, for each device tested here (or even others), we list the issues with it, at what time they appeared after buy and how many people got he issue?

So we would have, not only the measurements, but also the long-time realiability of them.
 
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