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Power amplifier tests with respect to FTC: 16 CFR Part 432 (July 5, 2024) requirements on output power claims

@amirm can I ask how long your power sweep tests dwell at or near full power?
As I explained, I run multiple tests that not only dwell near full power, but also go well past into clipping. Here is an example again:

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Usually post clipping measurements slow down. As an estimate, I would say it takes good few seconds from clipping point until the sweep finishes at the top of the red curve. And these points come after the amp was already pushed to produce max power.
 
By eliminating low cost options that exist today. This is the Amazon listing for aforementioned AIYIMA A07 amp:

Imagine modifying this listing and saying it produces 20 watts because that is what the FTC test mandates. The market may shrink substantially for this amplifier (especially since there will be others selling similar units at "300 watts"). Their option would then be to substantially enhance the cooling in the cooling, power supply capability or both. This will sharply increase the cost of these amplifiers (shipping costs alone would be killer).

I would challenge FTC on this and bring up the above as Exhibit A that consumers were perfectly happy with what was being offered and advertised. 1400 reviews averaging 4.5 stars means there was nothing broken for FTC to "fix." Nobody using that amp thinks it is only spitting out 20 watts as they are using it in real life situation with music, hearing far more power.

In other words, government meddling in the industry, increasing costs with no net value to consumers. After all, the market is open to companies over-designing products if that was what the market wanted.
Why would low-cost amplifiers be eliminated if there is still a market for them, even if their power output is limited? Consumers purchasing these amplifiers don’t suddenly require 20 times the power they had before. Your reasoning suggests that if some manufacturers make false claims, then everyone should do the same to level the playing field. In my opinion, that’s not a good direction to take.

Now, let’s consider a scenario where all amplifiers have FTC-compliant ratings. The playing field would be equal and more transparent. As I mentioned earlier, manufacturers could embrace this and use the FTC rating as a badge of honor, promoting their "real power" or whatever creative marketing concepts they come up with.
 
As the rules are currently structured, there is no obligation for the manufacturer to alter their design, as they only need to add the FTC-rated power.
These small amplifiers that are manufactured in China which seems to be the ones getting some up in arms have no obligation to do anything. The entity that would be fined is the importer or sales representative in the United States. I believe for a lot of these but not all that entity is Amazon.
 
High temperature is a critical factor for assessing the lifespan of electronics, particularly electrolytic capacitors.
Idle heat generation is what is going to cook those caps over time. Not what happens at clipping with sine waves.
 
Why would low-cost amplifiers be eliminated if there is still a market for them, even if their power output is limited?
Same amplifier power design will be sold on Aliexpress with 10X the power rating. Or even Amazon itself. You think folks will buy a 20 watt amp when they think they can buy a "300 watt" one for the same price?

You must think the wattage doesn't matter to consumers in which case, you should not be in favor of FTC anything.
 
These small amplifiers that are manufactured in China which seems to be the ones getting some up in arms have no obligation to do anything. The entity that would be fined is the importer or sales representative in the United States. I believe for a lot of these but not all that entity is Amazon.
Whether it's the importer or the manufacturer, targeting either will yield essentially the same results over time.
 
The two are linked and you know it. An amplifier that can easily cope with the preconditioning and the 5 minute full power test must be adequately thermally designed. It must have adequate reserves in SOA and that means more devices. It must have an adequate power supply. All those things mean a less stressed, less hot device in normal use and that bodes well for longevity. Don't pretend otherwise
You (and Pavel) need to distinguish between devices that fail, spark, smoke (which would absolutely impact MTBF values) and those with protection circuits. The latter improve MTBF.

Protection circuits are helpful in an apparatus room full of millions of dollars worth of gear. But if they are over-aggressive they are frustrating from a systemic availability perspective.

To be clear to everyone who keeps arguing that an FTC test failure points to understanding longevity - that is only the case if there are no protection circuits active!
 
Your reasoning suggests that if some manufacturers make false claims, then everyone should do the same to level the playing field. In my opinion, that’s not a good direction to take.
Nope. FTC ruling is what is going to create false claims. That an amplifier that can perfectly produce 150 watts, is now forced to be advertised at 20 watts. This is wrong and goes against the very motivation listed by FTC in its request for comments:

"Accordingly, the Rule standardized the measurement and disclosure of some, but not all, performance characteristics of power amplification equipment to“assure that . . . performance characteristics are based upon conditions of normal use by the consumer, i.e., conditions which are encountered in the home.”3"

It is trivial to show that sine wave testing for 5 minutes in no way shape or form is "normal use by consumers." This is why I say FTC regulations can be overturned. And why I won't adopt them.
 
The two are linked and you know it. An amplifier that can easily cope with the preconditioning and the 5 minute full power test must be adequately thermally designed. It must have adequate reserves in SOA and that means more devices. It must have an adequate power supply. All those things mean a less stressed, less hot device in normal use and that bodes well for longevity.
Only if it is made to be a much more expensive amplifier. The very thing I said is anti-consumer by taking away options that are optimized for music playback instead of passing FTC test.
 
Whether it's the importer or the manufacturer, targeting either will yield essentially the same results over time.
I doubt Amazon would be worried about it but if they get cited they would probably quit selling or allowed to be sold on their platform instead of bothering about it. I can't imagine these account for enough revenue for them to get involved but they might. Of course some of these small amplifier companies for instance Fosi you can simply order direct.
 
Idle heat generation is what is going to cook those caps over time. Not what happens at clipping with sine waves.
This particular discussion was based on the 1/8th rated power test, where heat dissipation is greater than during idle operation.
Same amplifier power design will be sold on Aliexpress with 10X the power rating. Or even Amazon itself. You think folks will buy a 20 watt amp when they think they can buy a "300 watt" one for the same price?

You must think the wattage doesn't matter to consumers in which case, you should not be in favor of FTC anything.
It depends on the marketing strategies and how well consumers are informed.

Accurate ratings are crucial, along with direct comparisons and a transparent market.
I believe it was John who mentioned the example of NAD, which, in the past, marketed their amplifiers with relatively low continuous power ratings but offered 4-6 dB of dynamic power.
 
Then they may haveto derate the performance for no good reason. its been wxplained several times. You are going around in circles.
There is no dispute that some amps are garbage and so are the claims made of their performance. thats not the point. This doesn't mean the FTC test is an appropriate solution.
Not for no good reason. For a good reason. -Transparency.
Circles indeed. :)
 
I doubt Amazon would be worried about it but if they get cited they would probably quit selling or allowed to be sold on their platform instead of bothering about it. I can't imagine these account for enough revenue for them to get involved but they might. Of course some of these small amplifier companies for instance Fosi you can simply order direct.
Certainly. However, direct orders from a manufacturer's webshop to the U.S. would also mean that the FTC could impose fines on them directly.
 
for instance Fosi you can simply order direct.
Now that you mentioned fosi,I think it would be good for them to lower the numbers they advertise.
Amazon warns about high numbers returned and at the mono thread they are some that failed (probably by testing them against the advertised power or abused at passive subs,again,cause of the rated power)
 
Back to the real world. It's doubtful These little amplifiers made in China would be affected. As far as I can tell in the 4 months this regulation has been in effect I haven't noticed any changes in advertised power ratings.
 
About consumers:
Today's picture is vastly different than few years ago.And the reason is DSP,RC apps,etc and their misuse.
We often see people at threads ironing lows by filling 10-15dB dips,multiple ones!NOT only at subs,but for example filling a desk bounce.
They also crank it up to add the loss these apps impose for headroom,digital clipping,etc.

Despite what we warn about,or try to explain.They just like watching this straight line and they don't give a second thought.
The power demands in such application is not only enormous but also continuous.And is encouraging to them to think they have all the power they need on tap.
Well,they don't.

Yes,bad practice but it's there way too often.
 
How does that work? The FTC fines Fosi whose webshop is in China? I guess the FTC could fine UPS or USPS for delivering them?
No, I believe they can be fined directly because, by operating a webshop and selling directly to U.S. customers, they fall under the jurisdiction of the FTC, regardless of their country of origin.
There's a link further upstream in this thread, I believe.
 
FTC "test" = reliability. Asserted with deeply felt emotion, but zero supporting evidence.

FTC "test" = useful data for consumers. Only for consumers interested in using the amp to run room heaters. It does NOT go to what consumers actually need for understanding how a product can suit their needs.

A few months ago, I was asked for my opinion by one of the entities commenting on the (then) proposed rule change. My input to them (which did not get incorporated into their comment, but I believe is pertinent), with a slight redaction for confidentiality purposes:

The way actual 3 letter bureaucracies work here in the US, who is president at any given time makes very little difference. This is especially true of niche areas like audio (as opposed to, for example, high-profile medical issues). XXX's remarks are reasonable, but IMO will only serve to make the specifications even more difficult for a consumer to understand. What the consumer actually cares about is, "Which of these two amplifiers I'm comparing will play louder with my speakers?"

There are (at least) two different issues: first, the standardization of the load. 8 ohms was something reasonable some years back, but it appears to me that a higher proportion of today's speakers tend to run to lower impedances. But that, of course, is the least of our problems- except for a few exotic choices (e.g., Magnepan). loudspeakers are usually reactive loads having highly varying impedances with frequency. And no two appear to be alike. There are certainly examples of amplifiers that are perfectly happy with resistive loads, but start having issues when the impedance starts swinging. In cases like that, a lower power amp with better load tolerance will be able to cleanly play louder. So what does the power rating tell the consumer in this case? Basically nothing.

Second, the issue that XXX raises, which is a realistic view of musical signal spectral content. This is a somewhat easier issue to attack- we use sine waves for ratings because we have always used sine waves for ratings. ;-) And this is mainly due to easily attainable measurement capability from a half century ago. There's no reason that with modern test gear and signal processing capability that we can't use something like repetitive pink noise or other spectrally shaped stimulus. Rather than THD, we could rate distortion as the RMS deviation of the voltage between test signal and (scaled) output to the load. This would inevitably pull in source impedance to the measurement for anything other than a resistive load, but that's not a bad thing since, besides low distortion, we want the amplifier to resemble a pure voltage source.

If they allowed me to be dictator of the FTC for a few days, I would probably incorporate a shaped noise source as the test signal, measure average power at a standard value of RMS deviation expressed as a percentage, and rate it at a 6R resistive load and a standardized complex load which would be vaguely representative of a large proportion of passive consumer speakers. The old 1/3 power sine wave preconditioning requirement would also need to be reworked since that's appropriate for last generation amps, not Class D. Perhaps running full power (as defined by my deviation proposal) with the shaped noise for some defined period might be suitable?

Of course, with the market moving toward active solutions, we may be worrying about standardizing the measure of the diameter of buggy whips
 
How so? Can you provide the MTBF figures for any of these 50 year old amps you are referring to? If not you have no basis to make that claim.

:facepalm: Just give it up. You look sillier each post you make.
 
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