Manufacturers want to loosen test conditions for their product to look better.
No manufacturers, such as myself want the test to be relevant and meaningful.
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Manufacturers want to loosen test conditions for their product to look better.
There is no universal and defined MUSIC, to be used as a standard. And not only 1kHz is requested, but sine waves from 20Hz to 20kHz. As John has already stated.
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@davidr3032
ATI aren't wrong. They are rating their product in accordance with the US rules.
This discussion has been had many times on ASR (and other places). Basically, the Hypex power ratings are not compliant with US FTC amplifier regulations, but, as they are only selling components (modules), not complete amplifiers, they can get away with it. It is up to the assembler/builder/manufacturer of the completed product to advertise their product in accordance with those regulations if sold in the US.
The EU regulations are much looser, and, with Hypex in particular, their specifications are cherry picked to look good. Not uncommon practice, many manufacturers do that. They are still an excellent product for many people, don't get me wrong.
The 20Hz-20kHz FTC rating means the minimum continuous average power at a specified distortion or lower can be achieved at any frequency across the specified bandwidth on a continuous basis. It doesn't mean all frequencies at once.
We all know that typical music has lower power demands at high frequencies, but that is irrelevant. It's just an excuse for covering up the inherent problems and un-levelling the playing field. In the case of the Hypex modules, it is more about the dissipation and destruction of the output filter capacitors at high power/high frequencies. They simply cannot deliver their full rated power at very high frequencies (20kHz) for more than a few seconds.
Once classD amplifiers improve with even faster switching devices, filter related dissipation issues will become less of an issue and we'll begin to see full power, full bandwidth ratings. I look forward to that.
In the meantime, you are doing well to be one of the few who read through the specs and into the nitty gritty. Keep up the independent thinking.
Yes they can output full power at 20kHz, but as I keep pointing out they will never need to to. No amplifier needs to.
They are not misleading, its been explained and demonstrated that they do what they say on the tin. They can sustain the quoted power 20 to 20kHz.I think it would be better if the manufacturers of hypex based amplifiers and other class d amps gave more realistic power ratings like the way ATI do. Then they could always supplemented those with further specs explaining what class d amps are capable of. The specs on these amps are impressive with low distortion and high damping factors etc. They have a lot going for them. So plenty of selling points without the misleading power ratings
Usually? Is there?OK thanks thats very interesting. As most amplifiers can't operate full power at 20kHz. Usually there's a drop of power at such high frequencies. Why do you think ATI have rated it 200w 20hz-20khz while you rate it at 330w?
You need to speak to ATI to answer that. pehaps they dont use an adequate power supply, I dont know.
Usually? Is there?
You need to speak to ATI to answer that. Perhaps they dont use an adequate power supply, I dont know.
Can I ask why you keep focussing on this particular point (20kHz) when its clearly not important or required?
No, thats just the requirement of the FTC. It has been clearly explained why it is of no relevance at higher frequencies, but just to make the point again, the Hypex amps have no issues with doing so.Because a power rating of an amp 20hz-20khz should include the frequency of 20khz
As I said, I dont know why they cant achieve the full Hypex performance spec, but I am suspicious about the use of a linear PSU. It would need to be very large to provide the 1kW needed for a stereo NC500 design.Yeah quite a difference from your specs. 200w compared to 330w. Are you suggesting that ATI have made a catastrophic mistake with their design?
No, thats just the requirement of the FTC. It has been clearly explained why it is of no relevance at higher frequencies, but just to make the point again, the Hypex amps have no issues with doing so.
BTW I just looked at the ATI website and they use their own linear power supplies, not the Hypex SMPS which the Hypex specs are generated with.
View attachment 106619
Its not just the requirement of the FTC its also the requirement of the end of the sentence "the power rating of the amp is 330w 20hz-20khz"
So you think ATI are using power supplies that are reducing the amps potential power rating by a huge amount? Thats quite a controversial conclusion
Once classD amplifiers improve with even faster switching devices, filter related dissipation issues will become less of an issue and we'll begin to see full power, full bandwidth ratings. I look forward to that.
No, thats just the requirement of the FTC. It has been clearly explained why it is of no relevance at higher frequencies, but just to make the point again, the Hypex amps have no issues with doing so.
BTW I just looked at the ATI website and they use their own linear power supplies, not the Hypex SMPS which the Hypex specs are generated with.
View attachment 106619
This is Amirs test of a Nord NC500 based amp. If you look at the graph it clearly matches the Hypex data.
View attachment 106620
View attachment 106621
Oh BTW there is a very good reason for only using 6kHz in a THD test. The 2nd and 3rd harmonics of 6kHz fall at 12 and 18kHz, ie within the audible range. If you test at 20kHz the 2nd and 3rd harmonics are at 40 and 60kHz which are well above the auditory, or speaker reproduction range.
Again its about having meaningful and relevant tests.
Sorry but of course he was testing the power rating.
His conclusion of 445 watts was at an arbitrary thd + n level of 0.003%. The level he chooses varies on each and every test. It should be consistent.
This is way before clipping. If you go down that road why not choose 0.0001%?
The FTC test is *not* a technical standard. It is for advertising rules in the USA *only*. I have explained why it is technically flawed. Please take this on board.
Amirs data is almost identical to the Hypex data. The Hypex data is not misleading as you have stated. It is accurate.
With the input of multiple posters in this thread hopefully you have now been given a better understanding of how to read the data.
You can choose to believe whatever you wish.
How is it "unlevelling the playing field" when say a 100 watt (at 1kHz) amplifier will never ever be required to output 100 watts at 20kHz?
Yes well exactly. Therefore the correct power rating is not 700w into 4ohm. Thats one thing we can say for sure. And its wrong for manufacturers to quote it as so. If it is 445w then surely manufacturers who quote 700w are misleading people. By a significant amount
But Amir isn't specifically trying to find the amps overall power rating here. He's merely simply stating the amp power before clipping is 445w. Which is great info to know
True but as the previous examples showed this might only be fractions of a watt.It will be required to wiggle the output voltage at 20kHz near or at peak voltage when the 20kHz signal rides lower frequencies near the power limits.
Just an observation, I have no further argument other than that.