Pro people around audio probably can tell,my installers advised me about 1200as's as a 300W amps despite the brochures (their positive advice was more in line of reliability) .But how will they know they've found an amp that can fullfill their needs if the power spec are unclear, that's the point of discussion I believe? It's not that Hifi amps than can deliver more than 50W continously don't exist. Looks like your best bet today is the size of the heatsinks and transformer instead of specs, altough with class D amps and SPS's it's more difficult to assess intuitively.
No. Your “pushing to the limits” is undefined (you never defined it exactly, you never shown the record of your test level sweep. And, speaking about what happens with music is again undefined and irrelevant, as we can find various very different samples of music with different crest factor and rms power over longer or shorter period of time. The main problem, to me, is that you call this forum scientific or reviews called scientific, which they are not. Definitions are vague and reasoning is based on opinions an emotions and not on facts and standards. If you clearly stated it is rather about business then I would be satisfied.My testing pushes the amplifiers well into clipping multiple times. This is precisely what happens during playback of music if the amp is pushed beyond its limit. That said, neither my testing or FTC requirements are reliability metrics/processes. I put myself to college repairing hundreds of amplifiers during the time FTC rules were in full effect. Whether something has an FTC spec does not mean at all that it is reliable.
To come up with any kind of reliability testing, you need to do far more homework than guessing here and there.
That's a great guide here:Following this with interest. No axe to grind on the politics or philosophy of all this. Is FTC compliance necessary, I don't know.
Standards are great, they allow meaningful comparison of Amps and there is a comfort in knowing that a manufacturer has the confidence to demonstrate compliance. Tests here are standard, so they allow comparison with other Amps *tested on this site* and that's helpful - it's still difficult to make comparisons with Amps that are *not* tested here.
If specifications are quoted then they should be met, and there should be no ambiguity (is reported power 'continuous', peak or other ... should be clear).
My main take-away so far is the importance of thermal management and specifically the size/effectiveness of the heatsink.
I still can't see any way of understanding what sort of heatsink is in various amplifiers. Perhaps it's in service manuals somewhere (where those are available), perhaps a manufacturer would just tell me if I asked them (not going to do that until I'm ready to buy).
I can see a use for FTC compliance as a proxy for confirming good thermal management - if the Amp passes the continuous power test then is was capable of managing the heat...
Not asking to be spoon fed and happy to do my own research, quite enjoying learning more about this stuff - really wish all Amps reported their specs in a consistent, comparable manner though. Seems to me that FTC compliance, apart from anything else, would help with that.
These class D amps with SMPS generally have issues at continuous very high power, due to economic overall design and thermal management including the SMPS used. The parts under thermal stress must lie directly on the heatsink with lowest thermal coefficient possible and enabling very good air circulation (fins, number of them, depth). Indirect transfer through Al base plate of modules does not work well.Even giant heat sinks won't make the "2x2000W" ICEpower 2000AS/2 deliver more than 2x280W according to my own tests.
You are absolutely right. I should have checked the datasheet before I ordered my modules....In defense of ICEpower, they do state solid specs in publicly visible datasheets that "everone skilled in the art" can double-check and confirm (which I did). This is OEM stuff and works exactly as advertised, and it's the burden of the implementer to decide whether it's going to be sufficient for the use case or not.
It must be said that testing the adequacy of the finished product heat dissipation system for every real world scenario requires extremely complex tests for an OEM. I don't even know if there is a standard in that.These class D amps with SMPS generally have issues at continuous very high power, due to economic overall design and thermal management including the SMPS used. The parts under thermal stress must lie directly on the heatsink with lowest thermal coefficient possible and enabling very good air circulation (fins, number of them, depth). Indirect transfer through Al base plate of modules does not work well.
Thanks @pma for this work and sharing it with us.Some of us feel the need of honest specifications of amplifier output power according to acknowledged documents like FTC regulations and IEC standards. The reason is to get comparable data, protect potential customers and draw attention to false claims of some manufacturers.
I have decided to make such tests myself ad so far I have tested several well known amplifier and also one of my DIY designs. The links to the tests and results can be found below:
That’s what this thread is about. Such marketing easily fools common consumers and they buy the product in a good faith, as they are unable to discover the caveats.But they do market them as 2x2000W amps perfect for subwoofers. They are NOT.
It is an abandoned law. No enforcement. No one cares about it. I think I have only seen one product that had a mention of FTC. Years ago, there were always footnotes about FTC power specs if not in the specs themselves. This hasn't been the case for years now.
Like anywhere else, there is marketing in order to compete and get noticed. I can tell you from personal contact with ICEpower engineers that they were not really happy about this marketing, again like anywhere else ;-)But they do market them as 2x2000W amps perfect for subwoofers. They are NOT.
Still about 2x of what the datasheet says, 2x135W.Even giant heat sinks won't make the "2x2000W" ICEpower 2000AS/2 deliver more than 2x280W according to my own tests.
Pro people around audio probably can tell,
Let's just start reporting each and every product ASR reviews (or any other remotely competent reviewer/tester) that DOES NOT reach its advertised, compliant power output to the FTC.