NAD M28 7 Channel Purifi Amplifier Teardown

[Digital Mastering System]

I wonder what they are using the MCP6002 for? It's a pretty crappy op-amp. Bad offset so not for dc servo. Low GBW product so mediocre distortion. It's very cheap however!

 

[Vasr]

Maybe in the past they had some deal with nad that was Licence/Royalty based because of mention that Nad where making slightly modify ones, but this here looks like the modules themselves. Unless something is special with Nad, Hypex/Purifi had and have, as far as I know an OEM business model. They shouldn't get royalties, You buy the number of modules you need and they are yours to use. That said I won't pretend I know the exact deal behind, but generally that's how they operate. Maybe Purifi isn't exactly like Hypex neither.

Distinction without a difference to the intent of the original statement (sardonic humor) that seems to have been missed. Whatever you want to call it, they get a cut for every unit sold by NAD so they can save the world and so.. oh never mind.

 

[Vasr]

Whats up with luxury companies being unable to even put at least top tier parts in their devices? If it's anything I would expect in the very least, it's that they do that.

But they have beautiful screws!

If you look at most "luxury" brand products. there is a difference between the care that goes into visible things and those that are hidden. The ratio between the two pretty much depends on the ratio of engineers to bean-counters that participate in the decisions.

 

[boXem]

I wonder what they are using the MCP6002 for? It's a pretty crappy op-amp. Bad offset so not for dc servo. Low GBW product so mediocre distortion. It's very cheap however!

It's for the audio signal detection for auto on/off, does the job, no need to spend more for this.

 

[bigguyca]

Whats up with luxury companies being unable to even put at least top tier parts in their devices? If it's anything I would expect in the very least, it's that they do that.

This is obvious, but bears repeating:

Luxury implies a high price and high customer acquisition costs. Many (most, all?) people equate quality with high price even if they fight that tendency. The correlation between price and quality, in design, construction and measured performance of a product, is often weak.

Assuming high quality in an AV product without the sort of measurements and teardowns performed by Amir is a mistake.

 

[PeteL]

Whats up with luxury companies being unable to even put at least top tier parts in their devices? If it's anything I would expect in the very least, it's that they do that.

I'm not gonna disagree with you with the fact that they should have better capacitors, but hey we live in a crazy world where some people have unlimited funds. Compagnies that are in the business of "luxury" sell their amps 100 000$ and use capacitors that are 200$ a pop. Not that anybody would need that, but that's luxury

 

[MakeMineVinyl]

It's for the audio signal detection for auto on/off, does the job, no need to spend more for this.

You would still need a relatively good opamp to do even this since there has to be a lot of gain to detect small enough signals so the amp doesn't shut down with quiet parts of a movie or music. If the opamp is too noisy, this would be hard to do.

 

[boXem]

You would still need a relatively good opamp to do even this since there has to be a lot of gain to detect small enough signals so the amp doesn't shut down with quiet parts of a movie or music. If the opamp is too noisy, this would be hard to do.

MCP6002 is used on the M22 for the same function. It happens to work.

 

[Daniel0]

Well, a 1600W Corsair PSU is like €500-600.

This PSU you are talking about is so expensive because of the 80 Plus Titanium rating. And you can't really compare PC PSUs to audio amplifier PSUs.

You can get Hypex PSUs like the 1200W SMPS1200A400 for 215 € tax incl. and the 3000W SMPS3kA400 for 290 € tax incl.
And that are single quantity end user prices, a big company would pay less.

 

[trl]

Samwha are pretty decent, but Lelon caps are just a cost saving decision and not really befitting of a product in the price range.

Well, 3000h @85C is still acceptable if you don't intend to use the amp for more than 1-2 hours per day, although for how much it costs I do feel that 7-10 thousand hours @105C caps might be a better choice here.

http://www.lelon.com.tw/upload/prod/158140387342.pdf

 

[PeteL]

This PSU you are talking about is so expensive because of the 80 Plus Titanium rating. And you can't really compare PC PSUs to audio amplifier PSUs.

You can get Hypex PSUs like the 1200W SMPS1200A400 for 215 € tax incl. and the 3000W SMPS3kA400 for 290 € tax incl.
And that are single quantity end user prices, a big company would pay less.

You are correct that they would pay less, but as a general rule of thumbs, mid volume manufacturers like this, that rely on the more "traditional" model of manufacturer-distributor-retailer, with street price slightly below msrp and with considerable marketing, cannot hope for a profit if their BOM cost is higher than one fifth to one sixth of the msrp. I'm quite certain that for this product they had a firm goal of 5k msrp, and I am not surprised by a few cost cutting decisions here and there to reach this goal. Of course, it's not the ONLY model, some are very small one man only craftmans, some use the direct from manufacturer online only model. And a healthy argument could be made if this traditional model is still being relevant. But NAD being NAD, this is what it is and looking at this I can easily see a 1000$ BOM here. Maybe even more.

 

[Koeitje]

This PSU you are talking about is so expensive because of the 80 Plus Titanium rating. And you can't really compare PC PSUs to audio amplifier PSUs.

You can get Hypex PSUs like the 1200W SMPS1200A400 for 215 € tax incl. and the 3000W SMPS3kA400 for 290 € tax incl.
And that are single quantity end user prices, a big company would pay less.

I was just showing that a very high-end power supply could easily fit in the BoM for a piece of gear like the M28. Of course that Corsair PSU is far more advanced.

 

[Casey Leedom]

Yes, I was discouraged enough by @amirm’s Performance and Teardown Reports that I finally just decided to sell the M28 immediately. I’ll take a ~$2,500 bath on that. I’ll count it as a good lesson regarding avoiding ”1.0” products. Entirely my fault.

Casey

 

[PeteL]

Yes, I was discouraged enough by @amirm’s Performance and Teardown Reports that I finally just decided to sell the M28 immediately. I’ll take a ~$2,500 bath on that. I’ll count it as a good lesson regarding avoiding ”1.0” products. Entirely my fault.

Casey

Ouch, any Idea what's going to replace it? Or just gonna wait for more options?

 

[Chromatischism]

Yes, I was discouraged enough by @amirm’s Performance and Teardown Reports that I finally just decided to sell the M28 immediately. I’ll take a ~$2,500 bath on that. I’ll count it as a good lesson regarding avoiding ”1.0” products. Entirely my fault.

I hope this is sarcasm. It is, right? It's so hard to tell these days.

 

[martin900]

Typical NAD...these things are made to fail within 5 to 10 years. Sounds good while it lasts.
Shame for the usual Chinesium capacitor garbage and AGAIN deliberately placed at the heatsinks, they have been doing this for years.

Saw an M2 at the repair bench at a friend of mine's repair place. He gave it back to the owner stating it's not worthwile even looking at it, too much SMD crapola and already crusty soldering joints.

 

[Digital Mastering System]

It's for the audio signal detection for auto on/off, does the job, no need to spend more for this.

I see. A cheap comparator. OK

 

[PeteL]

I see. A cheap comparator. OK

I'd be more worried about the other way around tough. Wondering if there is a vertical PCB that we don't see between the two sections, but there doesn't seem to be temperature control, or any obvious micro controller. Even just a PIC. Does this amp ever turn off in case of over heating or continuous clipping? No evidence of a soft start circuit neither, altough it could be hidden in the PSU, I don't pretend to have a full fuctional understanding of all of it.

 

[Feanor]

Typical NAD...these things are made to fail within 5 to 10 years. Sounds good while it lasts.
Shame for the usual Chinesium capacitor garbage and AGAIN deliberately placed at the heatsinks, they have been doing this for years.

Saw an M2 at the repair bench at a friend of mine's repair place. He gave it back to the owner stating it's not worthwile even looking at it, too much SMD crapola and already crusty soldering joints.

Golly, I guess I ought to unload my NAD receiver. It's been working fine all the while but is more than 10 years old so I suppose will give up any day -- actually it's a 7130 receiver: 35 years old.

 

[carlob]

Typical NAD...these things are made to fail within 5 to 10 years. Sounds good while it lasts.
Shame for the usual Chinesium capacitor garbage and AGAIN deliberately placed at the heatsinks, they have been doing this for years.

Saw an M2 at the repair bench at a friend of mine's repair place. He gave it back to the owner stating it's not worthwile even looking at it, too much SMD crapola and already crusty soldering joints.

In ten years there will be Class XYZ amps with sinad 280 and thd 0,00000000000000000000000000000001, your Nad will be a nice paperweight. Putzeys will be still around and he will say that his new design, the Spacex amp, sounds much better because it has a distortion of 0,0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001