Teardown of NAD M27 Surround Amplifier

[SegaCD]

Typical of Hypex builds, the capacitors are not tier one. They are made by Korean company SAMWHA:

Fortunately they are all rated at 105 degree C which is as it should be (rather the lower grade 80 degree C).

SAMWHA (a Samsung subsidiary) capacitors are notorious for being spec'd higher than they actually are and for having relatively short lifespans.

Samsung TVs use SAMWHA caps exclusively (obviously) so there is a large, consistent sample size to support this. The number of Samsung TVs with failed caps in the PSU is atrocious. Also, a lot of complaints of out-of-the-box "excessive plasma buzz" on Samsung plasma TVs could be resolved by replacing the caps on the high-voltage filter section of the x-main & y-main boards, proving that they were out-of-spec from the factory!

Its a shame that NAD couldn't couldn't get Hypex to use better caps (i.e. Nichicon, Rubicon) especially at this price-point... I'm more than slightly worried that many of these will fail prematurely as a result (or, at least, the capacitors may be hindering the performance of an amplifier that already measures wonderfully).

 

[Sal1950]

A lot of money for a legitimately good piece of gear that will probably be passed up soon by purefi and others.

Yea but generally amplifiers have been transparent for decades.
You don't buy these products on SQ concerns alone.

 

[speedy]

A lot of money for a legitimately good piece of gear that will probably be passed up soon by purefi and others.

This piece of gear came out in 2015

 

[VintageFlanker]

A lot of money for a legitimately good piece of gear that will probably be passed up soon by purefi and others.

Passed up? I beg to differ:
With highest distortion at -110db, this amp seems 100% audibly transparent. Whatever the Purifi or any other module is measuring better, probably none would hear a difference level-matched.
Also, these modules (first time I see an implementation of NC400 OEM, BTW) deliver quite more power than either 1ET400A or the AHB2.
So, not an overpriced 7 channel amp in my book.

 

[orangejello]

Same module and board for the stereo M22 and the 7 channel M27. Interesting reuse of parts.

I wonder why they used NC400 OEM instead of NC500 OEM, as they did with M22 v2.

Where did you get the idea that the nc500 is used with the M22 v2. I looked at my v2. It uses the nc400 oem. Is there a v2.1 version?

 

[orangejello]

Where did you get the idea that the nc500 is used with the M22 v2. I looked at my v2. It uses the nc400 oem. Is there a v2.1 version?

Ok. It appears that there are several modules at play. There is the nc400 DIY module which is circular and there is is the nc400 OEM which is what NAD uses and is on a square board.

 

[amirm]

It's not a filter but a passive PFC corrector. Also found in the Fusion 502/503.

I don't think there is any power factor correction in there, passive or otherwise. Here is how it measures when just powered on:

PF is power factor and is pretty low.

That module looks like ordinary set of chokes to comply with EMC rules.

FYI, it uses 97 watts while idle which explains why it gets warm when just sitting there.

 

[Matias]

Where did you get the idea that the nc500 is used with the M22 v2. I looked at my v2. It uses the nc400 oem. Is there a v2.1 version?

No, you are right, NC400 OEM on the V2 too as well. I was wrong.
https://www.audiosciencereview.com/...ments-of-hypex-nc400-diy-amp.5907/post-169131

 

[headshake]

Samsung TVs

Add computer screens too. I've personally replaced the caps in my sammy.

 

[boXem]

I don't think there is any power factor correction in there, passive or otherwise. Here is how it measures when just powered on:


View attachment 33764

PF is power factor and is pretty low.

That module looks like ordinary set of chokes to comply with EMC rules.

FYI, it uses 97 watts while idle which explains why it gets warm when just sitting there.

Didn't want to start a debate on this. Usually the PFC is integrated to the SMPS.
About idling, wondering if disconnecting the idling channels would improve the measurements like it did with the NC400 DIY.

 

[amirm]

About idling, wondering if disconnecting the idling channels would improve the measurements like it did with the NC400 DIY.

It would. But probably easier just to power it on to watch a movie and then shut it off.

 

[noel_fs]

plans on reviewing k5 pro @amirm ? sorry for commenting in a random thread about it but i guess its more efficient than creating a new one

 

[March Audio]

]


BTW, I was banned from the second thread. But of course, as a few know everything and they assume that I am the ignorant.

You are being ignorant if you repeatedly spam every thread with this which is specifically contrary to the advice of the designer.

Are you saying you know better tha Bruno Putzeys? If so add arrogant to ignorant.

 

[SEKLEM]

You are being ignorant if you repeatedly spam every thread with this which is specifically contrary to the advice of the designer.

Are you saying you know better tha Bruno Putzeys? If so add arrogant to ignorant.

Fella reminds me of a coworker of mine. He has an emergency light bar in his 90's Pontiac because he thinks it makes him look like a police officer.

 

[GWolfman]

@maty What's your native language (i.e., mother tongue)?