BUCKEYEAMPS Hypex NCx500 Amplifier 2channel Review

[Toni Mas]

I always wonder what happen when in for example APOEQ you put -12dB in the preamp.
The speaker become harder to drive? For example i have my R7s with a different EQ for LEFT and RIGHT, the thing is it's -12dB per channel..? So what ? xD now is -12dB less efficient my speaker?

No, It receives x16 less power

 

[BrokenEnglishGuy]

No, It receives x16 less power

So what..? too short answer
''It receives x16 less power'' this can mean a lot of things in this context

 

[Toni Mas]

So what..? too short answer
''It receives x16 less power'' this can mean a lot of things in this context

The speaker is the same, you have simply attenuated the driving signal amplitude 4 times, which is 16 times less power

 

[peng]

There's an AB "heavy" one at 300/600 watt with 3KW PSU.
I wonder what JA means by that "continuous"...

View attachment 304336

Esoteric Grandioso M1X monoblock power amplifier Measurements

Sidebar 3: Measurements

www.stereophile.com

For bench test measurements, the typically use the term continuous, if the test signal is a continuous sine wave, as opposed to a pulse signal.

If JA meant continuous to mean output at that level indefinitely, he would have to test the amp in a way that he can confirm the amp can in fact output at the 300/600 W level indefinitely.

I can be completely wrong about this. Specs like this, as well as dynamic headroom, power consumptions erc., can be confusing, as manufacturers don't seem to follow the same standards consistently, and don't provide much details either.

 

[Toni Mas]

For bench test measurements, the typically use the term continuous, if the test signal is a continuous sine wave, as opposed to a pulse signal.

If JA meant continuous to mean output at that level indefinitely, he would have to test the amp in a way that he can confirm the amp can in fact output at the 300/600 W level indefinitely.

I can be completely wrong about this. Specs like this, as well as dynamic headroom, power consumptions erc., can be confusing, as manufacturers don't seem to follow the same standards consistently, and don't provide much details either.

Manufacturers simply have to consider if their reputation is strong enough to allow realistic but "poorer" specs, or if as challengers they need more agressive claims. Sadly customers tend to believe any figure, simply cos' it's written!

 

[BrokenEnglishGuy]

The speaker is the same, you have simply attenuated the driving signal amplitude 4 times, which is 16 times less power

Thank you

So my physical pre-amp is attenuated(?)
And i will require the same amount of watts from my power amp for the same spl?


Sorry but for a long time since a lot time ago i have problems understanding how this specific thing works

I mean, it's a -12dB in each channel... is a lot of bass correction, but hey sounds fine in my small room

 

[Rick Sykora]

Thank you for providing additional information!

You are welcome and once I stepped back, while conditions matter, perspective does too. From the Hypex data sheet, I knew that the amp was capable of 700 watts while driving only one channel, I can see now that you may not have known. I did not know Buckeye’s posted spec was also claiming 700 watts. So can see why your review referenced that spec. I have discussed with him and he plans to update.

I look forward to seeing your updated review once you have the replaced the power supply. If you have any questions about the amp or my testing, you are welcome to contact me directly.

 

[tmtomh]

IR to chips GPU's / CPU's they are of course not run over 100 %. This is a definition question. Just as amplifier power. A GPU is limited to perform 100 %. This 100 % load is defined as various performance figures which the GPU/graphics card is guaranteed to do at a 100 % load. According to the design criterias different parts of the graphic card can be the limiting factor e.g. power limit by cooling design, GPU speed, VRAM speed, GPU voltage limit. When all of these criterias are considered for the specific card the specifications are then given and are below the threshold of the above mentioned limiting factors. Then the definition of 100 % is defined and the BIOS limiters are set so, that it cannot go further than the defined 100 % by limiting the factors above that cross the threshold.

This is actually a very good comparison to amplifiers as different components of an amplifier will be the limiting factor of the performance; power supply, cooling solution etc.

My point is that the 100 % load definition should at all times be below the threshold of damage to any component. Otherwise that value (for amps that is power) which is specified as 100 % should be lowered until no risk of damage is present. This is good design.

I agree with you that it's a very good comparison with amplifiers - but I agree for a different reason. Once thermal throttling becomes one of the means a CPU or GPU uses to keep from burning itself up, then you can't know with any precision what speed that CPU or GPU will actually run at - which is a perfect analogy to not knowing exactly how many watts certain amps can provide above 5-10kHz.

And once again, this is my point: CPUs and GPUs don't actually perform at 100% of their capacity indefinitely (unless they are unusually efficient or unusually well-cooled, and even then I can only think of one example of the top of my head that doesn't throttle at all.) So CPUs and GPUs are not actually different from amps in the way you are claiming.

 

[AdamG]

Let’s try and stay focused on the Amp tested, the methodology and the results. Take these side conversations to a separate thread please. This thread is long enough as it is.

Please and thank you for your cooperation and understanding.

 

[Doodski]

Seriously,
I never had need of more than 50 or 60 watts to damage my ears while listening ....
Hundreds of watts are needed for those who drive speakers with extended EQ far beneath the specifications of the speaker, or speakers that are very low on impedance and thus badly constructed ... or both.

I've handled some several hundreds+ of different amps and had the opportunity to have a comparator switchbox to compare them and about 120 to 130 good Watts per channel is the number where things happen and improve. Anything more is for difficult loads and dynamic transients. 50 Watts per channel is nice but it is lacking for the majority of speakers these days.

 

[xaxxon]

Manufacturers simply have to consider if their reputation is strong enough to allow realistic but "poorer" specs, or if as challengers they need more agressive claims. Sadly customers tend to believe any figure, simply cos' it's written!

We just need two numbers. A sustained number and a "musical" number at a specific X/Y ratio of peak to moderate power such as what is common in music. At that point, both can be tested and verified without harming the equipment.

But damn I love my bulletproof benchmark amps. Quintuplets of pride for me

 

[Hipocrates]

I would throw something in there about "standard musical playback level" or something... something to make it clear that the max number is the one comparable to (many?) other manufacturers.

In the 90's was called P.M.P.O, and was used freely on mini systems.

Seriously,
I never had need of more than 50 or 60 watts to damage my ears while listening ....
Hundreds of watts are needed for those who drive speakers with extended EQ far beneath the specifications of the speaker, or speakers that are very low on impedance and thus badly constructed ... or both.

or a good size room, somehow inefficient full range speakers, listening moderate SPL and want some headroom for demanding passages

For nearfield applications you have a good point.

 

[Deleted member 48726]

Seriously,
I never had need of more than 50 or 60 watts to damage my ears while listening ....
Hundreds of watts are needed for those who drive speakers with extended EQ far beneath the specifications of the speaker, or speakers that are very low on impedance and thus badly constructed ... or both.

Hundreds of watts can easily be needed for transients. 60 W amp ain't gonna cut it! EQ or not.
I disagree with you on that low impedance speakers are badly constructed. Look at all the small bookshelf speakers tested on here. The trend is and has been small slim speakers and small drivers. To keep the efficiency tolerable on those the impedance has been 4-6 ohm on many of them for years. I wouldn't call them "badly constructed". Well some of them I would, but not because of their nominal impedances..

I always wonder what happen when in for example APOEQ you put -12dB in the preamp.
The speaker become harder to drive? For example i have my R7s with a different EQ for LEFT and RIGHT, the thing is it's -12dB per channel..? So what ? xD now is -12dB less efficient my speaker?

No you just need to turn the volume up 12 dB more than you used to. Nothing to do with power. All to do with gain structure in your system.

For bench test measurements, the typically use the term continuous, if the test signal is a continuous sine wave, as opposed to a pulse signal.

If JA meant continuous to mean output at that level indefinitely, he would have to test the amp in a way that he can confirm the amp can in fact output at the 300/600 W level indefinitely.

I can be completely wrong about this. Specs like this, as well as dynamic headroom, power consumptions erc., can be confusing, as manufacturers don't seem to follow the same standards consistently, and don't provide much details either.

Yeah, those terms can be misleading. Continuos should ideally mean that the amp is run at the load until temperatures has stabilized and not rising. Further investigation during testing protocol could be to do the test again but now with the lid off and do some FLIR photos of components. -A method that is revealing a lot of information about what to expect in general IR to durability and longevity.

 

[Toni Mas]

For amplifiers people generally stick to the rms value based on a sine waves with the associated peak value of rms X2 (x1,4 squared) and generally people ask to make sure if rms or peak and distrust anything else.
For loudspeakers this X2 ratio is widely considered overkill and AES admits a x4 ratio (6db crest factor) but the peak value is not often mentioned and 2 figures are generally used, the aes/rms value and the so called program value, rms x2. Seems that the peak is considered little serious and seldom mentioned, though peaks are real.
It seems that manufacturers claiming pmpo invented figures have made a dreadful harm to the industry and its credibility ..

 

[Apollon Audio]

I've handled some several hundreds+ of different amps and had the opportunity to have a comparator switchbox to compare them and about 120 to 130 good Watts per channel is the number where things happen and improve. Anything more is for difficult loads and dynamic transients. 50 Watts per channel is nice but it is lacking for the majority of speakers these days.

 

[peng]

Yeah, those terms can be misleading. Continuos should ideally mean that the amp is run at the load until temperatures has stabilized and not rising. Further investigation during testing protocol could be to do the test again but now with the lid off and do some FLIR photos of components. -A method that is revealing a lot of information about what to expect in general IR to durability and longevity.

I would a little more details, that is, "....has stabilized and not rising" above the safe operating limits of the power supply, output devices and other parts of the dut.
Case in point, if the power supply has block capacitors (for class A, AB types) rated 85 C, then temperature should stabilize well below that, in order for the measured power output to be rated "continuous indefinitely".

In my opinion, I would want manufacturer to provide more details, such as multiple power output ratings:

1)100 W 8 ohms, 130 W 4 ohms, phase angle <=45 deg, 20-20,000 Hz, THD+N <=0.05%, both channels driven continuously, ambient 25C
2)120 W 8 ohms, 150 W 4 ohms, under the same conditions except both channels driven continuously for <=5 minutes

2) must be tested per the previously enforced FTC Rule 432 that specifies:

Standard Test Conditions 432.3 e:

Rated power shall be obtainable at all frequencies within the rated power band without exceeding the rated maximum percentage of total harmonic distortion after input signals at said frequencies have been continuously applied at full rated power for not less than five (5) minutes at the amplifier's auxiliary input, or if not provided, at the phono input.

Most bench testers would not likely complain about the 5 minutes requirement. Manufacturers likely would comply as the risk of the dut being damaged is lowered by a relatively short 5 minutes duration.

 

[peng]

BUCKEYEAMPS Hypex NCx500 Amplifier 2channel Gain High 4 Ohm 5 W 22.4k SINAD 256k Temp 26.8 Humi 54%

Few points to consider

1. Mistaken rated power marking

To produce 700 W x 2 Ch output, It needs way more power consumption.

After I fried the amp and checked, It uses a Hypex SMPS1200A700 power supply. This is rated up to 1200 W which is less than 600 W per Ch.

Possible Efficiency of Class D AMP -> about up to 90%.

600 W x 90% = 540 W but, this is just an ideal value, so in practice a value of about 10 W less than this may be the rated output.
So, current setting could be rated as near 530 W or under.

I understand buckeyeamp will update the information. If he rate the amp in accordance with the information Hypex data sheet provided, it would fix those points except:

Your comment on the efficiency may confuse some readers who may not have read the SMPS1200/700 data sheet that says the following:

The efficiency as specified by the datasheet is 92% and the Pmax is 1350 W, not 1200 W, you seem to have mixed up the power consumption figure with the power supply's power output.

How about 700 W?
700 W x Ch = Power supply output W x Efficiency of Class D AMP -10W x Ch
1420 W / 90% = Power supply output 1578 W

Again, I think you might have mixed up the SMPS1200/700's power consumption and power output specifications. Hypex did not say the PS is rated for 700 WX2, but more like 600 WX2, for 10 seconds, with heat sink temperature at 95 deg C.

1200/92% = 1304 W, that is close enough to the specified power consumption.

Due to calculation, About 1600 W PSU is required to stably output 2 channels of 700 W is estimated.

Thanks to you and others, I trust buckeyeamp would be updating the website information soon. I guess he will have to be careful with the wording, as in this case there are two pieces, the PS and the Amp modules, and he is sort of the integrator, who has to be clear and accurately reflect the specifications provided by Hypex on both components. In this case, the SMPS could be used for different amp modules, and likewise, the amp modules could be used with different PS, that sort making specifying the combined unit, i.e., the power amplifier slightly more complicated.

2. Protection did not work properly until amp finally self-destructed.

You may be right but you don't know for sure until you know what is "work properly". As you know, Hypex designed those amps for use with "music program", so they might not, or might, have designed the protection schemes for the way you or others set up the various test conditions.

Thanks again for providing so much bench test results, a great service to us indeed, my comments are not intended to be critical of your work at all, but only to try and help reduce (hopefully) the potential of the a few of the comments made might have been misleading, or confusing, unintentionally, of course.

 

[delta76]

Not a useful data. Dont care at all!

well, you might not, but far more people would care if an amp (or any equipment) can perform according to specs.

 

[Toni Mas]

well, you might not, but far more people would care if an amp (or any equipment) can perform according to specs.

Sorry, dont remember what i was talking about... And of course i dont see any need for everybody to agree on everything ...

 

[tmtomh]

That video has already been analyzed and critiqued here; it's almost certainly not accurate.