Hypex Nilai 500 DIY Stereo Amp Kit Review

[terryforsythe]

You two are talking about this one at -105dB which I highlighted yellow?

Yes.

That's not DC, that's 1kHz. The chart is at 5k intervals:

The harmonics are at 1kHz intervals. Count the number of harmonics below 5kHz. I'm counting 5.

 

[terryforsythe]

I wonder if the buyer participates in ASR. Was leManu's build defective or the system it was in or was leManu hearing things or what? 'Tis a mystery.

Yes, a mystery.

After putting mine together, I don't know how someone could screw it up. But, you never know.

When I first put mine together I still had my Adcom GFA-5802. I did not do a blind test, but quickly swapping between the two I didn't hear an audible difference.

 

[Sokel]

Yes.


The harmonics are at 1kHz intervals. Count the number of harmonics below 5kHz. I'm counting 5.

Now that you say it, you're right,it's not a log chart, my bad.

 

[TNT]

(Nope, it's not a log chart, scrap that)

You see, even a seasoned guy like you get a bit confused by the scaling. And it changes between reviews which I think is unfortunate. Why?

//

 

[RogerSmith]

What???

what I wanted to say is some measurements (SNL etc.) are so good, they are usually only be seen for DACs, not for amps

 

[JW001]

Just curious as a non-engineer normie, do these class D amps ever get as warm as class A amps that people had for decades?

To help understand the efficiency of class D amplifiers, one has to realize that their power stage operates in a pulse mode, where transistors are always in one of two states: "on" or "off". When in "on", the voltage drop on the transistor is close to zero, when in "off" - the current flowing through the transistor is close to zero. In both cases the dissipated power, P = U * I, is close to zero.

(In reality, there is a third state, the transition between "on" and "off", where the U * I product is not close to zero, making the class D less efficient.)

All in all, the efficiency of class D may be somewhere between 80 and 90%, whereas class AB - 50 to 60%. The class A is the worst, about 20 - 25% efficiency, meaning that the power stage transistors dissipate in the form of heat 80% of the supplied power.

 

[amirm]

what I wanted to say is some measurements (SNL etc.) are so good, they are usually only be seen for DACs, not for amps

They are different products so measurements are tailored for them. For example, power measurements don't mean anything for DACs. Likewise, Jitter measurements don't apply to amps.

 

[RogerSmith]

They are different products so measurements are tailored for them. For example, power measurements don't mean anything for DACs. Likewise, Jitter measurements don't apply to amps.

I am fully aware of that, thanks.

 

[KL....]

It's not really a class D problem, but one of perspective. You look at the rising distortion towards 15kHz, and think it's somehow bad - it isn't. It only looks that way because below that, distortion is so low.

Thank you, @Ropeburn, to ask.... what does this mean/imply for the connected Speakers (the ClassD Amp/Speaker combination), especially with Volume/Power?

 

[Ropeburn]

Thank you, @Ropeburn, to ask.... what does this mean/imply for the connected Speakers (the ClassD Amp/Speaker combination), especially with Volume/Power?

It means nothing. The distortion at 15kHz is still very low. If you send a 15kHz signal full power, the speaker will get an additional 30kHz at -85dB or something. That's nothing.

Nothing to do with amp class either. An old AB amp with much higher distortion will send more HF signal to the speakers in the same scenario. That's never been a problem either because it's still low.

 

[KL....]

It means nothing. The distortion at 15kHz is still very low. If you send a 15kHz signal full power, the speaker will get an additional 30kHz at -85dB or something. That's nothing.

Nothing to do with amp class either. An old AB amp with much higher distortion will send more HF signal to the speakers in the same scenario. That's never been a problem either because it's still low.

Thank you, @Ropeburn, what does this mean/imply for Low Frequencys/LF and Low Mids freqs with the connected Speakers (the ClassD Amp/Speaker combination), especially with Volume/Power?

 

[Ropeburn]

Thank you, @Ropeburn, what does this mean/imply for Low Frequencys/LF with the connected Speakers (the ClassD Amp/Speaker combination), especially with Volume/Power?

I don't understand what you're asking. What has any of this got to do with class D? Distortion is distortion. On this amp it's very low across the whole audio range. That means it'll put out a very clean signal. Done.

 

[AudioSceptic]

I have this amp which I converted to dual mono recently. My only concern is that the case is poorly vented, with only a pinhole grid in the top cover. I'm considering modifications to improve airflow.

Surely they would've made sure it's enough, and it's good to stop stuff falling in?

 

[AudioSceptic]

The case gets quite warm to the touch after several hours of use, or on but sitting idle. I'm very happy with the performance of this amp and plan to keep it. One lesson I gleaned from this site is that heat is the enemy of electronic components so I would like to do what I can to improve cooling.

I'd do some proper temp monitoring before messing around with the casework.

 

[AudioSceptic]

I like the low profile look, on the other side I wonder if by having such a small case, will the heat impact the long term reliability.

There's enough space inside and the top has a decent area with many small vents so what else is needed?

 

[Karmacoma]

There's enough space inside and the top has a decent area with many small vents so what else is needed?

I thought the top was too low, you can extend these modules' lifetime by just lowering the temp of a couple degrees so I like to see a bit of volume, but following comments of actual owners told me it was fine, so, ok.

 

[terryforsythe]

I thought the top was too low, you can extend these modules' lifetime by just lowering the temp of a couple degrees so I like to see a bit of volume, but following comments of actual owners told me it was fine, so, ok.

Also, the temperature rise is a function of the surface area of the case, not the internal volume. Making the case a little taller won't do much in terms of controlling the temperature.

As I previously noted, in stock form it ran cool enough that I did not have any concerns, even in a closed cabinet. It wasn't until I added the second power supply that I grew slightly concerned about leaving the cabinet door closed, but even with two power supplies it still ran cooler than my old Adcom. As I noted, adding just a small amount of airflow to the cabinet erased any concerns I had.

 

[AudioSceptic]

Also, the temperature rise is a function of the surface area of the case, not the internal volume. Making the case a little taller won't do much in terms of controlling the temperature.

As I previously noted, in stock form it ran cool enough that I did not have any concerns, even in a closed cabinet. It wasn't until I added the second power supply that I grew slightly concerned about leaving the cabinet door closed, but even with two power supplies it still ran cooler than my old Adcom. As I noted, adding just a small amount of airflow to the cabinet erased any concerns I had.

In particular, the surface area of the top, because any warm/hot air inside rises towards it.

 

[Sokel]

In particular, the surface area of the top, because any warm/hot air inside rises towards it.

The whole real estate can be calculated and also we can see the differences or heatshink fins orientation, case thickness, etc.
The guide, calculator and the math:

How to Select a Suitable Heat Sink

Laptop computer designers, audio amplifier makers, and power supply manufacturers can keep their products cooler by following these fundamental heat-sink

www.designworldonline.com

 

[AudioSceptic]

The whole real estate can be calculated and also we can see the differences or heatshink fins orientation, case thickness, etc.
The guide, calculator and the math:

How to Select a Suitable Heat Sink

Laptop computer designers, audio amplifier makers, and power supply manufacturers can keep their products cooler by following these fundamental heat-sink

www.designworldonline.com

No excuse for not getting it right then!