Probably the most dummy load tests wanted,POWERSOFT

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#84
jan.didden said:
I fail to see the difference in measurement-methodology in these cases for class AB or class D. The principle is the same, no?
Click to expand...

Principle is the same. Conclusions slightly different. Most class AB amps don't have a strict low-pass filter on the input.

Another thing is that when troubleshooting a class D amp it is pretty important to test for oscillation at far higher frequencies than at what you usually measure a class AB amp.
 
#85
Ok, let's say for you, tests on square wave isn't relevant as no needed :joker: .

Let's go back at first post where the most important discussion must be taken about output power in 2 ohms each channel.

As you see in that picture 2 ohm is recomended: 🙂

http://postimg.org/image/3neo5fqtr

So if in prospects power for 2 ohms is 5900-6000 watts per channel both channels driven: :joker:

http://postimg.org/image/c6y236z67

Tell me please in first test movie, where ate those 6000W/2R claimed? :witch:

pay attention from min 1.05

https://www.youtube.com/watch?v=QjGHKoTKRjk

Is a short peak of 104-107vrms in hard clipping, unacceptable in mine opinion for an professional amplifier like that, to see hard clipping on output, especially at that amount of power (dangerous for speakers) and thereafter just 63-64 Vrms sustained on output for couple seconds, then one short big burst and after on output not even those 63 Vrms to be clean, the sinusoidal becomes traiangular and therefore thermal limit (min 1.26 and further).

So what do you have say about that?

There are those 12Kw 2x6000?

In dreams maybe...
 
#86
I didn't watch those movies, but if it is what you say, are you sure the specification was 6kW RMS, or was it 6kW peak?

Sometimes these specs are confusion, also because manufacturers try to get the highest numbers they can get away with.
We all remember those small PC speakers specced at 200W/ch, which was actually the very short term power to be coming out of the power supply, but had nothing to do with the produced audio power.

So what does the 6kW (or whatever) spec actually say? Are they saying 6kW continuous RMS? I would doubt that.

Edit: I looked at the 2nd movie, looks indeed like a very short term peak power. I can't understand the language so I don't know what is actually claimed, but the video clearly shows short term peak power and sustained about 63V RMS in 2 ohms which is almost 2kW.

Jan
 
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#87
They said 2x6000Watts on 2 ohms, their specifications, not mine.

View image: 2 Ohm

If you have a gig, on wich power you are based, short, burs,t peak PMPO, whatever kind of power or RMS power?

Don't take me please with crest factor 12db or music signal is not as sinewave, etc.

We discuss here REAL, RMS sustained power.
 
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#89
So if those short term peak of 104Vrms (aren't anyway 6000 watts/2 ohms) you said that's those 6000 watts, what's happening after?

Why just 63Vrms on output and in couple seconds thermal limit?

Why doesn't able to sustain even those 63 volts on output (around 2100 watts/2 ohms)and gets into thermal limiting, and sinusoidal signal on output becomes triangular and after squarewave in less than 20 seconds?

A not able to handle 2 ohms on output?

So why wrotte that?

2 ohms recommended? http://postimg.org/image/3neo5fqtr

A, an 2 ohms speaker not dummy load?

Ok then, 4 speakers of 8 ohms (6,8 ohms resistance measured at 25 celcius degrees) put in parallel measures as real resistance of 1,7 ohms, much lower...
 
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#90
Honestly, look at the amp - it is 1 unit of height and claims 2 x 6kW. Remember it needs more than that at the input of the class D converter - say 13kW or more??... The power supply for continuously feeding > 13000W into the class D section would take typically almost 3 units of height alone. And I am talking of high end topology like bridgeless PFC plus LLC main converter. Remember that you need double that power during sine peaks which has to be provided through a big bank of electrolytics at low frequencies (if you do not want to feed that momentary power demand by the main converter which is a bad idea btw.) Anything to add here?
Test it on 8 Ohms and see that the measurement comes much closer to what you expected. That is exactly the best way to operate these things - on 8 Ohms. Continuous 2 x 6kW into 2 Ohms is THAT ridiculuous I would not even waste 5 seconds thinking about that..
 
#92
Wanna see what I mean REAL SUSTAINED POWER of 2x 1200Watts RMS/4 ohms at threshold of limiter?

Wanna see what I call an good limiter from an amplifier?

Wanna see how one good design amplifier performs on square wave?

Be my guests, in english for you.

Enjoy and comments are welcome, even they are good ones or bad ones.

That's what I call one good amplifier for entire audio band 20Hz-20KHz not because it was made by me, just because it acts correct on output, no matter even on low or maximum output power, even on low or overloaded input level or signal form, sinusoidal, triangular and square wave...

View image: Carcasa Sursa (1)

View image: Carcasa Sursa Module (2)

View image: Amp Complet Sus

View image: Amp Complet Fata

Video, testing, (in english) so everybody can understand it:

https://www.youtube.com/watch?v=_7tp79uYl7U&feature=youtu.be

https://www.youtube.com/watch?v=usE0XeCnDhQ&feature=youtu.be
 
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#94
Just for compare with that powersoft regarding his limiter, his waveform signal when limiting, the general audio response in entire audio band, and how he acts when overloading by 400% input signal (powersoft hard clipped the output).

I know you have nothing to comment, because looks almost perfect on different type of signal one DIY home made amplifier compairing to one modern, thousand euros amplifier.
 
#95
DjLeco said:
So if those short term peak of 104Vrms (aren't anyway 6000 watts/2 ohms) you said that's those 6000 watts, what's happening after?

Why just 63Vrms on output and in couple seconds thermal limit?

Why doesn't able to sustain even those 63 volts on output (around 2100 watts/2 ohms)and gets into thermal limiting, and sinusoidal signal on output becomes triangular and after squarewave in less than 20 seconds?

A not able to handle 2 ohms on output?

So why wrotte that?

2 ohms recommended? View image: 2 Ohm

A, an 2 ohms speaker not dummy load?

Ok then, 4 speakers of 8 ohms (6,8 ohms resistance measured at 25 celcius degrees) put in parallel measures as real resistance of 1,7 ohms, much lower...
Click to expand...

Why do you ask me? I only pointed out that you interpreted what you saw/read was different from what is really there.
If you want to know why they did it the way they did, ask them 😉

Jan
 
#96
So, 94 for posts later, not to mention a whole lot of pigheadedness, we conclude that some arbitrary RF-capable amp is better at producing square-looking square waves into 2 Ohms than some other, quite different device, with different constraints and advantages, costing 1000 Euros? The fact that so many hung on to this thread, including myself, seems to indicate that there is indeed a worthwhile discussion lurking here. If there indeed were a way to go forward, said pigheadedness might have to find a way to alleviate itself of its burden. I'm trying to convince myself that language might have something to do with this, but the convincing seems to break down on every re-reading of what has been said.
 
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#97
A huge output amps no need to be good at high frequency and NO WAY the huge amps can be made as good as small amps for the clarity at high tone.

We call it trade off in design to get maximum result. In this case the huge amps will be used for sub and low. If you need amps for mid hi then find other amps. Many manufacturer did that trick. In fact it is just fulfill the demand on market.

The problem is that we sometime have misunderstanding. We think that an expensive amps with huge outputs can do all jobs. That is wrong.
 
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