Review and Measurements of Hypex NC400 DIY Amp

[restorer-john]

The speakers also burn out if the amplifier does not have enough power when it enters clipping.

Speakers (particularly tweeters) are destroyed with ease when amplifiers are grossly overloaded and burst into uncontrolled oscillations in and around the onset and well into clipping.

This is a fact. Not a myth.

 

[Julf]

The speakers also burn out if the amplifier does not have enough power when it enters clipping.

Mostly because amps actually produce much more than their rated power when driven to clipping.

Worthwhile reading: An analysis of speaker driver failure

 

[Julf]

Speakers (particularly tweeters) are destroyed with ease when amplifiers are grossly overloaded and burst into uncontrolled oscillations in and around the onset and well into clipping.

This is a fact. Not a myth.

Yes, for some badly designed amps. Competently designed amps don't burst into uncontrolled oscillations.

 

[pma]

Inferior in which specific ways? And don't forget, they didn't sell conventional supplies, so a seriously vested interest in selling SMPSs.

• Reliability? No chance, not even close.
• Heat production? Worse in SMPS, particularly at low loads.
• Cost? Similar.
• Weight? SMPS wins
• Complexity? SMPS loses.
• Resistance to overload? SMPS loses.
• Resistance to line related surges? SMPS loses everytime.

Hi John, and do not forget that SMPS's are limited re output current. As a result, there is lower power of Hypex NCxxyyMP modules into 2ohm and in BTL mode, than they would have with a linear supply. As an example, my NC252MP 2x250W/4ohm amp gives 1x400W/4ohm in BTL mode, but my class AB 2x250W/4ohm amp gives 500W/4ohm in BTL mode. Not that it is a big difference, but it is. There is also a difference into lowest bass, power at 20Hz/4ohm is lower with SMPS supplied modules.

 

[Julf]

• Resistance to overload? SMPS loses.
• Resistance to line related surges? SMPS loses everytime.

I have to disagree on both of those. Any evidence for your claims?

I would also add "Decent voltage regulation? SMPS wins.
Noise rejection? SMPS wins.

 

[Julf]

do not forget that SMPS's are limited re output current.

So are conventional power supplies. So if you are comparing two power supplies with different current capabilities, it doesn't say anything about SMPS vs conventional.

Actually SMPS's often have better peak current capability for the same average current capability when compared to conventional power supplies.

 

[Julf]

Is it just me, or is there more and more "handed down wisdom" and less and less science here on ASR?

 

[restorer-john]

So are conventional power supplies. So if you are comparing two power supplies with different current capabilities, it doesn't say anything about SMPS vs conventional.

Actually SMPS's often have better peak current capability for the same average current capability when compared to conventional power supplies.

Hardly.

Transformer based supplies win hands down in the peak/overload current as compared to their rated continuous.

 

[Julf]

Hardly.

Transformer based supplies win hands down in the peak/overload current as compared to their rated continuous.

Any evidence for that claim? Traditional power supplies rely totally on the reservoir capacitors for peak current.

 

[restorer-john]

I have to disagree on both of those. Any evidence for your claims?

Plenty. Years and years of dead SMPSs on my bench. What do you have?

 

[restorer-john]

@Julf Your advice to @Martin3508 is skewed, does not present a balanced view and now you are doubling down in every aspect where you have been called, by those of us with decades of experience.

Not a good look, but whatever- knock yourself out.

 

[Julf]

Plenty. Years and years of dead SMPSs on my bench. What do you have?

Years and years of dead traditional power supplies. And tons of SMPS-powered gear (in fact data centers with thousands of them) that have been working years and years 24/7 without problems.

Do you have any actual statistics?

 

[Julf]

@Julf Your advice to @Martin3508 is skewed, does not present a balanced view and now you are doubling down in every aspect where you have been called, by those of us with decades of experience.

Not a good look, but whatever- knock yourself out.

Ah, we are getting into the ad hominem phase.

Can we have a rational, fact-based discussion, please?

As to "decades of experience", let me just point out that you might not be the only one...

 

[Sokel]

Hi,
You missed the point completely. Class AB amplifiers consume more power at idle, and as per my example more than 2x. In fact the Nad seems to be consuming much more than expected for some reason for a class D amplifier.

Given todays cost of energy, 61watts for a class AB stereo amplifier doing nothing is a waste, and scaling up for an active system makes it quite a bit worse. Class D offers the potential for a lot less wasted energy.

Regards,
Shadders.

It's not only Nad,mine (class D) consumes 30 watts idling,40 watts with another 2channel board connected to it.
The little I have searched,has to do with the add-on features (monitoring,etc).

 

[pma]

My NC252MP eats 17W at idle and half of that eats the SMPS

It is another myth that class D are always "Greener" than linear amplifier. Depends (idle current etc.). Class D starts to be efficient only at high output power. And normally the average power during listening is not high.

 

[restorer-john]

Class AB amplifiers in general consume very little power at idle. Typical 30-50wpc channel vintage integrated amps barely crack the 10W idle on my bench. And that's the whole amp, preamp and power stage. It's the bigger, deep class AB high powered amplifiers that pull more.

 

[Julf]

It is another myth that class D are always "Greener" than linear amplifier.

Pretty much anything that uses the word "always" is a myth.

 

[BeeKay]

Well 17W (Hypex in my Buchardt amp) idle vs 60W (classic AB with toroid in my Lindemann) is quite a difference to me.

 

[RickS]

I had a friend send me his Emotiva XPA-5 Gen 2 to test. I remember it well as it was a 70 pound beast and a back breaker whenever I needed to move it. Pretty sure it had linear power supply. Gen 3 uses SMPS and is 20 pounds lighter. It appears the amp modules each have their own power supply, so if one fails, the rest of the amp keeps working. For the linear design, recall the amps shared power. So, when the power supply fails, the whole amp is down.

A quick Google search for studies on linear vs switching power supplies did not yield any major reliability data. So, may be stuck with anecdotal evidence. In that case, application matters. As with the Emotiva I mentioned, SMPS can make a difference. We know most professional amps use switching power supplies. @amirm did some power testing for DACs a while ago, make me wonder if it may be time for another test?

p.s. By way of AH review, the linear powered XPA-2 was 45 watts at idle. So my buddy’s XPA-5 was much worse and am sure played into his decision to replace it with a 6 channel Buckeye NC502MP amp.

 

[Julf]