Review and Measurements of Hypex NC400 DIY Amp

[Sokel]

Try it with standard-rate DSD (64).


Indeed. DSD only has a SNR of 6 dB, but gets away with it by using noise shaping to shift it to inaudible frequencies.

Yes DSD64 looks horrible,on the other hand we have the standard DAC filtering that saves us:

But why use it when we can do much better higher?

 

[Julf]

But why use it when we can do much better higher?

Why use DSD in the first place? Anyway, my point was about the "If I feed in a pure 1Khz tone into a 'switching amplifier' and it produces anything other than that 1Khz tone, would you concede it has failed as a "straight wire with gain"?" argument from restorer-john.

 

[Sokel]

Why use DSD in the first place? .

Depends on the machine,as it seems some handle things differently.
The one you see compared does much better with DSD as the measurement shows,no grass (and it would be even better if my ADC wasn't hot for full output as it should be (I have to built voltage dividers ASAP)

 

[Julf]

Depends on the machine,as it seems some handle things differently.

Sure, depends on machine. I would just go for a DAC that does PCM well, instead of dealing with all the conversions - but we are seriously straying from the topic.

 

[Sokel]

Sure, depends on machine. I would just go for a DAC that does PCM well, instead of dealing with all the conversions - but we are seriously straying from the topic.

Seems it does ok with 109 SINAD (link),not a champion of course.
But does even better with DSD in terms of grass.
But you're right,we way OT.

 

[AnalogSteph]

If I feed in a pure 1Khz tone into a 'switching amplifier' and it produces anything other than that 1Khz tone, would you concede it has failed as a "straight wire with gain"?

It's an audio amplifier, and it's amplifying stuff that humans can hear just fine. Isn't that enough?

As long as out-of-band noise is not bothering attached speakers one iota (and the amplifier does not react to ultrasonic input with audible distortion), who cares. Dealing with measurement artifacts is up to the person doing measurements. If getting the required performance from Class D requires noise shaping but still leaves you with an efficient, compact, cool-running amplifier, so be it. It's called engineering tradeoffs.

BTW, if you want to see out-of-band shaped noise screwing with measurements, any CS4272-based audio interface with a fairly minimal output stage should do - see Amir's Arturia Minifuse review, for example. That's a rather old DAC design going back to 2000's CS4392, with very few bits and something like 5th-order noise shaping if memory serves.

 

[Vive la dissonance!]

Those high frequency tones from the top Class D amps (at the switching frequency) aren't just outside of the audible range for humans, dogs, or frankly even goddamn bats, they're far outside the possibility of being reproduced as actual sounds by any tweeter ever made, as far as I know.

 

[Johnplayerson]

Yes, but when you design a thing like that, you account for ESR and ripple current rating. Make no mistake, the large caps used in class AB amps eventually fail, too.

Yes, I have some amplifiers waiting 35 years and still no cap failure on the big mains. Caps will all fail eventually, but SMPS capacitors are stressed, and require even better and higher quality standards. The function is also different, mostly filtering out all that EMI and RF crap that SMPS generates. Capacitors in old school amps do not have to filter out that crap. Also capacitors in an SMPS are highly frequency dependent. All the cap needs to do is fall off spec a small amount and you have a cascading failure. Not the case with old school construction.

THe only way they can decrease the PSU failure rate is add heat sink and cooling, and or somehow get capacitor manufacturers to make more 130c 25000hr caps that can hold there spec longer.

 

[Doodski]

Yes, I have some amplifiers waiting 35 years and still no cap failure on the big mains. Caps will all fail eventually, but SMPS capacitors are stressed, and require even better and higher quality standards. The function is also different, mostly filtering out all that EMI and RF crap that SMPS generates. Capacitors in old school amps do not have to filter out that crap. Also capacitors in an SMPS are highly frequency dependent. All the cap needs to do is fall off spec a small amount and you have a cascading failure. Not the case with old school construction.

I estimate I've replaced several hundred+ caps that where at the output of PWM car audio amplifiers. They take a beating.

 

[Sal1950]

As far a I know, this ST70 was all original except the tubes and still
worked just fine when I sold it in 2010.

 

[Johnplayerson]

I estimate I've replaced several hundred+ caps that where at the output of PWM car audio amplifiers. They take a beating.

It would seem to me that the industry embraces SMPS power supplies that much more, because they create repeat business down the road. If you can market something, and get a customer to accept a 4 or 5 year operation life... with them saying, WOW that amplifier was good, I am going to buy another one, then you have generated a repeat customer through planned obsoleteness. This acceptance has always been much higher in the car audio industry, as with 14 volts , you need to resort to 2 ohm loading to get high power.

The other thing I do not like, is that it use to be if someone said an amplifier was 200 watts, It was automatically assumed that means into 8 ohms. Today you got to recheck as that may mean 4 ohms, or even 2. And as restorer john has said.. most times this is just peak power that can be measured, and I Johnplayerson, has always said, Just because you can measure power does not mean it reproduces an audio signal.

The industry has had many years to make the SMPS supply of higher quality, yet the max one sees capacitors , is usually 2000hr at 105c. and you do not see super high quality caps in the supplies, like UCC KZN or UCC KYB, which are extremely high ripple, low esr. 10000hr long life capacitors. Manufacturers get these capacitors for peanuts, yet would still want to save dimes and nickels on capacitors , rather then supply a higher quality product.

Also, not a lot of talk about build quality!!! Have any users disclosed the actual capacitors used in these units? THe manufacturer brags about efficiency and compactness. This is always the main talk... never about real quality issues.

This person can't even tell what the capacitor is, and another says he can possibly tell after he removes it. Weird that the failure here , is not even an electrolytic.

Hypex SMPS1200 faulty capacitor

Hello, I have some DIY Ncore NC500 amps, using SMPS1200A700s which are now out of warranty. One of the of the modules, a capacitor has started physically degrading, and generates a big spark to ground every time the amp is turned on. Does anyone know what this part is? I can't see any...

www.diyaudio.com

 

[Johnplayerson]

As far a I know, this ST70 was all original except the tubes and still
worked just fine when I sold it in 2010. View attachment 254552
View attachment 254553

Minimite Dynaco long life capacitors. I like the name lol

 

[Julf]

It would seem to me that the industry embraces SMPS power supplies that much more, because they create repeat business down the road. If you can market something, and get a customer to accept a 4 or 5 year operation life... with them saying, WOW that amplifier was good, I am going to buy another one, then you have generated a repeat customer through planned obsoleteness. This acceptance has always been much higher in the car audio industry, as with 14 volts , you need to resort to 2 ohm loading to get high power.

I think that almost veers into conspiracy theory territory. No, that is not the reason the industry is going SMPS, and it is a funny comment in a discussion about Hypex amps, as both Hypex and Bruno have been pretty clear about why they prefer SMPS:s.

The other thing I do not like, is that it use to be if someone said an amplifier was 200 watts, It was automatically assumed that means into 8 ohms. Today you got to recheck as that may mean 4 ohms, or even 2.

Yes, I think that is a huge improvement. It it so frustrating to see manufacturers who quote the output power only at 8 ohm. It is easy to accomplish a lot of power into 8 Ω, much harder into 2 Ω.

 

[Sokel]

The industry has had many years to make the SMPS supply of higher quality, yet the max one sees capacitors , is usually 2000hr at 105c. and you do not see super high quality caps in the supplies, like UCC KZN or UCC KYB, which are extremely high ripple, low esr. 10000hr long life capacitors.

What about the KMH series?Are they decent or...

 

[restorer-john]

Also, not a lot of talk about build quality!!! Have any users disclosed the actual capacitors used in these units? THe manufacturer brags about efficiency and compactness. This is always the main talk... never about real quality issues.

We've had those heated discussions over the years and guess what? It seems that Hypex has finally listened!

Have a look at the new Hypex Nilhai modules and power supplies. They use absolute premium capacitors in the pictures I have seen of both the amplifier modules and the dedicated SMPS. Nichicon, Rubycon, SME Chemicon and Panasonic. Whether that will continue into long term production- who knows.

Also, they have listened and improved the mountings for the primary switcher FETs and the secondary rectifier diodes packages.

 

[Johnplayerson]

I think that almost veers into conspiracy theory territory. No, that is not the reason the industry is going SMPS, and it is a funny comment in a discussion about Hypex amps, as both Hypex and Bruno have been pretty clear about why they prefer SMPS:s.

Yes, I think that is a huge improvement. It it so frustrating to see manufacturers who quote the output power only at 8 ohm. It is easy to accomplish a lot of power into 8 Ω, much harder into 2 Ω.

It really does not go into conspiracy theory. They teach planned obsoleteness in business school. The most common one was the standard light bulb that could be made to last forever unless it it broken, but are deliberately made to burn out. The people that make these products are engineers. They know darn well if a product is going to last a long time, or likely a few years.

Usually an 8 ohm amplifier will put twice the power into 4 and more into 2 as long as the output transistors are plentiful Back when I bought the Yamaha mx 1000u in 1988 or so. I bought it for the 260 watts into 8 ohms. Never did care about the the fact it could do 1000 into two ohms. Two ohm loading is just a shortcut to more power, and a recipe for disaster, that should be refrained from, not embraced. Zero ohms is a dead short, and the closer you encourage people to drive their amplifiers closer to dead short loads , the sooner they will fail. The marketing looks good however, showing off peak power levels, of a duration of which , no music signal will even be reproduced.

• 260 Watts (8 ohms) from 20 to 20,000 Hz at no more than 0.003% Total Harmonic Distortion.
• 295 Watts (6 ohms) from 20 to 20,000 Hz at no more than 0.007% Total Harmonic Distortion
• 330 Watts (4 ohms) from 20 to 20,000 Hz at no more than 0.02% Total Harmonic Distortion
• Dynamic Power per channel (by IHF Dynamic Headroom measuring method)
• 8 ohms/6 ohms/4 ohms/2 ohms/1 ohms 450W/560W/740W/960W/1000W

Remember all those qsc smps quality amps everyone bragged about? The only one left is the QSC pl 380. Every single other model is toast, and for good reason!!!.

 

[Johnplayerson]

We've had those heated discussions over the years and guess what? It seems that Hypex has finally listened!

Have a look at the new Hypex Nilhai modules and power supplies. They use absolute premium capacitors in the pictures I have seen of both the amplifier modules and the dedicated SMPS. Nichicon, Rubycon, SME Chemicon and Panasonic. Whether that will continue into long term production- who knows.

Also, they have listened and improved the mountings for the primary switcher FETs and the secondary rectifier diodes packages.

The name brands are better but are they using the higher temp, longer life caps. Rubycon yxf is a fairly inexpensive cap that is 10000hr at 105c. NIchicon He would be another. If they are dropping capacitors like this in there, at least there is an attempt to make a lasting component. My favorite are UCC KYB and KZN. They started using a new modified electrolytic in these caps, to get higher specifications with lower size.

Its great to make new products, but manufacturers have produced SMPS, and used consumers as guinea pigs for 20 yrs now. Yet you can still find amplifiers like powersoft, costing thousands of dollars, failing. All because of the less heat sinking, the inferior parts, and the small form factor, yet they continue to sell us all on how this is BETTER?

 

[Julf]

It really does not go into conspiracy theory. They teach planned obsoleteness in business school.

I am fully familiar with planned obsoleteness, but you have to remember that the main customers for Hypex are not consumers.

Usually an 8 ohm amplifier will put twice the power into 4 and more into 2 as long as the output transistors are plentiful

Indeed. Usually the output transistors aren't "plentiful". Most amps get current limited below 4 Ω, many even sooner. The Hypex ones are one of the few that go down to below 2 Ω.

 

[Johnplayerson]

I am fully familiar with planned obsoleteness, but you have to remember that the main customers for Hypex are not consumers.


Indeed. Usually the output transistors aren't "plentiful". Most amps get current limited below 4 Ω, many even sooner. The Hypex ones are one of the few that go down to below 2 Ω.

Yes and their current business to business warranty is less!!! then other warranties. Just because other business are their customers means nothing. Many audio manufacturers end up supplying amplifiers to other business, weather that be a venue actually using them, a rental business, or people buying there stuff and OEMing their own product.

Monoprice made a deal with them, and all these deals are based on the profit motive. The only company I know of willing to warranty for 5 years!. At the same time your paying twice the price for a lot less reliable amplifier then the monolith series.

Its not likely any of this stuff is going to be still operating 10 yrs down the road, and we have already seen what is happening.

3000 USD lol
https://www.monoprice.com/product?p_id=42564

vs 1800 for the transformer based monolith 7

I am really not into paying the kind of money these people ask, paying huge dollars for amplifiers that will not last , and will never increase in value like what happens with high end amplifiers from the old school. With the short life, at least one can buy a new power supply , or buy new modules, but they do not exactly give these 1000 dollar pocket modules away. The buy high quality once and forget it philosophy is dead, and the new industry loves it.

Hypex 2ohm.. Anyone that does so is asking for trouble sooner rather then later, and all their power ratings are bs burst, under the new rules adopted to make these types of amplifiers look better.

On a side note, i once wondered how Kramer could warranty all their SMPS powered products for 7 years. When i took it apart, the power supply was completely laden with rubycon 10000hr 105c caps. Have not seen another product yet , laden with such high quality capacitors.

 

[Julf]

Yes and their current business to business warranty is less!!! then other warranties. Just because other business are their customers means nothing. Many audio manufacturers end up supplying amplifiers to other business, weather that be a venue actually using them, a rental business, or people buying there stuff and OEMing their own product.

Yes, we know. Warranty isn't the issue. Do you think people like NAD would be happy to give Hypex repeat business if the reliability was bad?

I am really not into paying the kind of money these people ask

Then, if I may ask, are you participating in this discussion thread?

Hypex 2ohm.. Anyone that does so is asking for trouble sooner rather then later, and all their power ratings are bs burst, under the new rules adopted to make these types of amplifiers look better.

If you say so. My 8 nc400's seem to have been perfectly happy all these years. As to the "new" rules, they have nothing to do with class D.