iNUKE NU-6000DSP power load test

[Martin Rehak]

Hi all, today I get two amplifiers Behringer iNuke NU-6000DSP. My previous amplifiers was QSC RMX5050 - two pieces.
One week ago, I test output power of QSC RMX5050 to 2x4 ohm load (resistor 5kw, not speakers) with input sine wave 1kHz.
QSC RMX5050 have 85 volts on both outputs (2x85v - not bridged)
QSCRMX5050 is amplifier with power 1800W to 4 ohms (1kHz). So, this is real power.

iNUKE NU-6000DSP
This amlifier is ROHS, soldering without lead. The soldering is very, very bad. You can see on photos.
I dont use this product for profesional use. Is possible, that after the first show will be fire, or broken show.


The data from metering.
This amplifier have wroten 2x3000W into 4 ohms. This is 110Volts on each output.
If I load outputs to 4 ohm resistor, and inputs sine wave 1kHz,
Before light limit led (red) on each channel, I have 50V on each channel, after 5s each channel was alternately on and off.
I get on output maximal 55V on each channel, then amplifier shut down. For continue, I must restart - switch off and switch on.

Power is P=U*U/RZ
maximal power is 625W into 4 ohms for each channel (1kHz tone), manufacturer wrote 3000W !!!

[Christian Boche]

Hi Martin,

this is the typical behavior of an amp with pwm psu. Rating amps with 1kHz sinus is not common anymore. Most amp measurements are done with short signals with a crest factor, which is closer to real music than a pure sine wave. But I guess you already know that. The RMX5050 has got an toroidal transformer (that's why it is heavy as hell too). This old amp design shine, when they have to deal with sine wave. So, unless you are doing lot's of gigs with electronic music (where sine waves can happen), all class D amps has to lower their output power after a few ms. My Lab Gruppen's FP 10.000 are showing the same behavior for example. After a few ms with a sine wave input, they step down to 4 x 600 Watt as well. Just sayin'

Can't comment on the pics, they are too small on my laptop.
Christian

[Glenn Slater]

Hi Martin,

We are very sorry to see that you received units in the condition that yours are. If these are new units that you have purchased please contact our service department or your retailer. Please also be aware that in opening the units you may have voided the warranty on these units.

I am posting below an excellent answer by Mr. Behringer in response to power rating questions:

"Your question about power amplifier ratings is an interesting one for several reasons. Although over the years there have been attempts at standardizing the way power amplifiers are measured and rated, it appears to me that even in the face of legislation, there continues to be no consensus in the pro audio industry.
Forgive me for stating what you already know , but for some readers a bit of history may be in order.

There was a time when the accepted method for measuring amplifier power was to inject a sinusoidal signal (usually 1 kHz) and measure the output just as the sine wave began to distort. This type of measurement assumed that the amplifier would be operated in that manner, although we were all aware that actual program material was very different to a sine wave. Regardless, this RMS measurement became a standard.

While there have been several variations on this theme, the net effect of standard practice has always been that power measurements have been based on a continuous sinusoidal signal applied at the input. As imperfect as this system may have been, it did allow consumers to compare one amplifier to another and conclude which one had a higher rated power. Sounds good? Not so fast.

The problem with this method is, as most manufacturers and users discovered over time, that it measures a parameter that may not necessarily be the best predictor of actual amplifier performance. Real program material, whether it be music or speech, is very different from a sine wave and it is a leap of faith to correlate one to the other. Imagine a car that is capable of pulling a heavy load up a mountain compared to one that accelerates aggressively; which one is more powerful? It depends on what your objective is.

I believe that this disparity between what was measured and what was really needed was driven by the measurement technology of the day. In fact, the use of a steady-state sine wave is a throw-back to a time before digital oscilloscopes and programmable signal generators, when pretty much any technician could replicate the measurements on their test bench. Regardless of whether it was the “right” measurement, it was at least a measurement that almost anyone could make.

In the last 10-15 years we have seen the emergence of a whole new breed of amplifiers with power ratings in the thousands of watts, not just hundreds. Respected brands such as Lab Gruppen and Powersoft have led the way into this new realm not by measuring amplifiers the “old” way using a steady-state sine wave but by other means that more closely mimic the dynamics of real program material. The objective is to better quantify the performance of their products in the actual environment where they will be used.

Inherent in this approach is a lack of agreed measurement standards and definitions. I have yet to see published documentation on the precise measurement methods and techniques used by these and other manufacturers claiming specifications based on "maximum output power".

I can only assume that capable engineers are using good judgment in creating test routines that inject impulse signals of sufficient amplitude and duration along with periods of reduced energy to arrive at their power ratings. In any event, most manufacturers must consider this proprietary IP as they are not publishing such data currently.

This brings us to the iNUKE series of power amplifiers that BEHRINGER introduced just over a year ago. iNUKE amplifiers were the culmination of extensive research and development in our engineering team around power efficiency. As I have said in other posts we proudly operate one of the most capable power engineering teams in the industry with extensive experience in both SMPS and Class-D amplification.
Our new patent-pending "Class Zero" technology that combines power supply and amplifier into a single stage was in fact a direct outcome of the research the preceded the iNUKE range. With this new "Class Zero" technology, we have been able to design amplifiers with up to 94% efficiency (AC to AC), which is a remarkable increase of 10-15% compared to the most efficient SMPS and Class-D designs. The final component count and cost will have to be seen until the mature design stage, but energy efficiency in light of carbon footprint reduction and green energy is definitely worth pursuing.

I am proud to say that iNUKE amplifiers have become a tremendous commercial success and are now outselling even our EP4000; one of the most successful power amplifiers of all time. They have also earned the praise of users and the press, who have conducted their own independent testing.

. While we always support standards and also ensure that all of our products are UL listed and FCC compliant, even though many of our competitors skirt the law (try searching www.fcc.gov to see who has been fined for non-compliance), it appears that power amplifier measurement standards have not kept up with measurement technology.

If such a standard does come to pass, then rest assured that we will follow it right along with venerable competitors such as Lab Gruppen, Powersoft, Crown and QSC among others."

Uli
Last edited by Uli Behringer; 07-08-2012 at 08:40 PM.
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Here is a link to the original post:

http://soundforums.net/varsity/4299-...group-q-8.html

I hope that this is helpful to you.

Best Regards,

[Martin Rehak]

Hello Glen and Christian. Have you explanation for quality of soldering? Because it, what I see inside of iNuke is work of china people without rice. I am afraid, that if I use this amp on the first show, after the first song show end.
I am not amateur, my job is electronic design, instalations and pro sound. I see a lot of amplifiers inside, for example Crown, QSC, and other class amps, neither looks as (I want to be polite)...
I thing, that price of iNUKE NU-6000DSP is lower than 10 dolars.
Sorry. I can not disseminate good ad.
I do not believe your inuke amps.

[Martin Rehak]

in any literature that deals with the measurement of class D amplifiers is that the power is measured in the same manner as a linear amplifier, and a sine wave at 1 kHz. Is it true that this method of measurement is only for the usual linear amplifiers. If my amplifier BEHRINGER NU-6000DSP proves maximum 50V output at 4 ohms, 625W amplifier has, nothing more, nothing less.
Marketing theory about power 2x3000W are designed for amateurs and young children. This amplifier is not professional, there is a high risk to use it on any live show. And not just because of the lies about his performance, but mainly about his production quality, or better, not quality.
Mechanical construction is so unstable that his estimate lifetime maximum of three years and then toss in the trash.
After the audio page, I can not really recommend to anyone. High frequency sound, like when sand is poured on the plate. Bass frequencies sound like a broken drum.
It's a great shame the company Behringer, anything like that will launch and then shows how it has a positive reference.

He surprised me a qualitative difference between the production of iNuke and X32. When I saw disassembled X32 inside, it looks professional, but even so, time will tell. Cheap Chinese capacitors and switching power supplies have a very limited life and threaten the whole.
One thing is certain. Inuke you never not buy and instead I get a real professional amplifier.

[Glenn Slater]

Hi Martin,

It does not look or sound like your NU6000DSP's are working properly. There are tens of thousands of these units in use all over the world operating without a problem. The pcb in your photos do not look like what would normally leave the factory, so we will bring this to the attention of our service manager. Please tell us which dealer these units were purchased from.

Best Regards,

[Martin Rehak]

Here is QSC amp Class-D, measurement by sine wave 1kHz.
http://www.qscaudio.com/products/amp...owerlight3.htm
So, I dont thing, that on class-D is not need test by sine wave.

[Martin Rehak]

Hi Glen, both units are from Thomann musik haus. Today, I will send both units for change for any other both units, and after I get new two, I can try both on show, I will see, how quallity have iNuke

[Christian Boche]

Hi Martin,

when it stated that "sine waves" were used for an amp measurements, you can be sure, that nine times out of ten these sine waves are "burst sine waves"! I'm not aware of any pro audio gear magazine, that uses continuous sine waves for amp measurements anymore. Due to the nature of pwm amps, it just don't make any sense. Using burst signals is way closer to the musical input signals, that amps have to deal with. The transients of a kick drum are just 20 or maybe 40ms long, after that transient the signal strength goes down very quickly.
In addition it is true, that there are no real official test methodes for power rating amps! This makes it even harder to compare amps just by plain figures. This is why most pro audio magazines use different measurements signals (with burst and different crest factors). Two examples:
Maybe have a look at this Powersoft Digam K10 review-->

http://www.equaphon.com.ar/pdf/sopor...ionpartner.pdf

They used five (!) different testsignals for rating the power (continuous output, crestfaktor 6,12,18 and peak maximum).
For rating the continuous output they used a sine wave at 1K, BUT it is a bust signal - NOT a continuous signal. That is a huge difference.

Another example, different magazine:

http://www.tools4music.de/uploads/tx...dstufe_low.pdf

They tested also with burst signals (50ms long).

Like I said, if I would tourture my FP 10.000 with continous sine waves...they're rated with 4 x 2.500 Watt and will quickly reduced to 4 x 600 Watt by the pwm psu. This is the nature of this amp design. Given that, it shows that your measurements are probably right, but your preconditions aren't.

Christian

[Martin Rehak]

I have debated you put performances with the engineer, who also develops amplifiers, also class D. It states that you, as a manufacturer, you should state the products at their actual performances with their description, not only 2x3000W, but also which type of exercise is. As an example, take the other manufacturers, such as QSC provides three kinds of performances from their amplifiers. One of them is continous 1kHz. Otherwise, we believe that it is a fraud against the customer, in the EU it is called consumer deception. I would recommend that you have a description of amps, at least on its website include additional real and measured data, not some virtual numbers, which is practically impossible to achieve, or lead to the destruction of the product or production.

It is not true what you state here that it never reached in practice sine signal input. An example is a long guitar booster, or tone of the keys, or the DJ production is achieving the highest performance.