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

As a side note I would expect to have the informed opinions of the other side at this thread,there's a bunch of them otherwise very vocal,both assemblers and designers.
They must have some more info about it.
Don't want to tag them but silence is strange.I would expect they were the first to participate.
That's an excellent question.
 
Humorous response on a different thread on the "5 minute" rule. Looks like a more reasonable test employed as well.

Post in thread '2nd generation EIGENTAKT PURIFI 1ET6525SA (successor to the 1ET400A)' https://audiosciencereview.com/foru...a-successor-to-the-1et400a.56549/post-2156364

Thanks for the reminder about this - much appreciated.

I think it's useful to put that exchange in this thread too, so here it is:

Honest specifications is also called a hobby? What would be the rated power tested by a 5 minutes continuous sine test at 1kHz into 4 ohm and 8 ohm, all channels driven?
No idea, we are selling electric sound amplifiers, not soldering stations. Our amps are able to withstand (no shutdown for whatever reason) CTA-2034 pink noise at clipping onset for 30 minutes, all channels driven.

So one way we could think about this is this: Is there any scientific or engineering basis upon which to make a reasonable judgment about which kind of test is more useful to determine amplifier capability and robustness:
  1. White noise at full power for 5 minutes, or
  2. Pink noise at full power for 30 minutes
Putting aside the ad hominem for the moment (which I admit I've engaged in a bit here out of frustration), I can look at any sampling of @amirm 's recent comments in this thread and find arguments and rationales for a test more in the neighborhood of test #2. I cannot, however, say the same for @pma 's and @restorer-john 's comments on behalf of the FTC test, which is more in line with test #1.

The only clear argument I see in their comments on behalf of a text more like test #1 is that the acronym "FTC" is equated with "the only ethical and proper type of test."

But to my eyes, that equation is precisely the question we should be discussing, not the answer that allegedly ends the discussion.

In that vein, it's quite rich for @pma to have descended into accusing @amirm of hand-waving, when his and @restorer-john 's increasingly nasty and increasingly ad hominem jabs at Amir are fueled by a fetish for the FTC test without a willingness to engage in reasonable discussion about the merits of the specific parameters of that test. Yelling "FTC! FTC!" over and over again is basically the definition of hand-waving.

To the more reasonable participants in this discussion, I think it makes sense to ask the kinds of questions they've been asking, for example:
  • Does the FTC test provide good insight into amplifier power capabilities?
  • Are there other tests that provide equally good or better such insight?
  • Does the FTC test allow for useful and sensible comparative data on amplifier capabilities?
  • Does the FTC test provide useful insight on thermal performance?
  • To what extent is thermal performance correlated with long-term amplifier reliability?
  • Is any data available on the average failure rate of amps from the 1970s and '80s versus amps from the last 5-10 years?
And I would say that some progress towards answering those questions has already been made in the thread, but it has been obscured by some of the more strident and ad hominem responses.

Finally, it seems to me that none of the above questions were intended to be part of this thread, as @pma clearly created this thread to document the beginning of what could be a listing or database of amplifier power ratings based on his testing method - which, if I read some of @amirm 's comments correctly, is not even necessarily actually the FTC testing method.

So what Pavel is trying to do here is to expose ASR's membership to an alternative set of specifications for modern amplifiers, based on a test procedure that might or might not fulfill what the FTC guidelines say. His obvious and intentional focus in the tests so far is Class D amps, and he is using the large membership and traffic on the ASR site to drive eyeballs to that information. Not for any financial motive of course, but rather to try to get people to go by his power-rating figures rather than the ones Amir determines in his reviews.

That's fine, I guess. But let's no one be under any illusion that Pavel is interested in actually discussing the kinds of reasonable questions being raised by many in this thread, which I've tried to summarize in the bulleted list above.

Fortunately no one here gets to unilaterally decide what a thread ends up being about as long as the comments are generally on-topic. So personally I would encourage folks to keep discussing those questions, and to ignore the absolutist tirades about ethics, morality, and deception.
 
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Apologies for my ignorance again. I am curious if anyone knows why the FTC settled on this full power for five minutes test? I am ignorant when it comes to amplifier design, but just having followed this thread, have concluded it is pretty unhelpful and it would seem there are better options available (No2 above, being a prime example.)

Edit: Speaking purely as a layman - All I really hope to come out of this is more realistic (continuous?) power specifications and the reassurance as a consumer, that specifications and claims are based on reality...
 
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Apologies for my ignorance again. I am curious if anyone knows why the FTC settled on this full power for five minutes test? I am fairly ignorant when it comes to amplifier design, but just having followed this thread, have concluded it is pretty unhelpful and there are clearly better options available (No2 above, being a prime example.)
I think you could ask 10 people that question, and get 10 different answers - IE we don't know. Only FTC could answer it.
 
As a side note I would expect to have the informed opinions of the other side at this thread,there's a bunch of them otherwise very vocal,both assemblers and designers.
They must have some more info about it.
Don't want to tag them but silence is strange.I would expect they were the first to participate.
Well, since boXem has been mentioned, my first and last participation to the thread (that I did not and will not read) : FTC = US, boXem = EU. So I won't comment on US requirements.
 
OK. I find it curious that the US, which I always thought of as having less/laxer business restrictions etc than the EU, have this extremely stringent FTC reg...
 
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OK. I find it curious that the US, which I always thought of as having less/laxer business restrictions etc than the EU, have this extremely stringent FTC reg... My 2c

That's a good point. The US is this way in other areas too. For example, the US often has more stringent safety and legal requirements - for example you tend to see a lot more safety signage and disclaimers in the US, along with things like more stringent or uniform requirements for things like stair railings and other safety infrastructure at tourist sites and so on.

Some of it, I think, is the more litigious culture and ease of filing lawsuits in the US. And that, in turn, seems to come from the fact of weaker labor movements and virtually nonexistent regional or national left parties in the US. I mention this because in much of Europe, labor, socialist, and green parties can spur - and from what I can tell, have spurred - policies that regulate business on a systemic level, while in the US a lot of business regulation or restrictions have been spurred from lawsuits pursued under the banner of consumer's rights.

The FTC rules are of course not the product of a consumer lawsuit (as far as I know, anyway), but I would suggest that the general cultural difference I'm proposing here could have an effect on the entire climate of regulation.
 
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You could apply different pow depending on product category.

A utilitarian low cost device made to make the most music for the $ will try to optimise for “music” and “normal” use .

Luxurious “engineering porn” items at the real high end at eye watering cost I would pretty much expect to produce full power until I kick the bucket .

I think both product categories can fail us in different ways.

Cut one corner to much for the budget amp or in case of high end to much voodoo and cargo cult engineering the freaking thing weighs 100kg is very expensive and still fails spectacularly.

If I where a billionaire I would buy Accuphase not DartZeel for amp jewelry for example.

For a budget amp I would consider a hypex or purify box over some of the far east imports due a better and older track record.
 
Apologies for my ignorance again. I am curious if anyone knows why the FTC settled on this full power for five minutes test? I am ignorant when it comes to amplifier design, but just having followed this thread, have concluded it is pretty unhelpful and there are clearly better options available (No2 above, being a prime example.)

Edit: Speaking purely as a layman - All I really hope to come out of this is more realistic (continuous?) power specifications and the reassurance as a consumer, that specifications and claims are based on reality...

Congrats poster #900!;)

All that I have seen I had posted earlier. it was a quote from Dennis Murphy on Audioholics. He commented that any FTC test "had to be based on continuous power".
 
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  • Does the FTC test provide good insight into amplifier power capabilities?
  • Are there other tests that provide equally good or better such insight?
  • Does the FTC test allow for useful and sensible comparative data on amplifier capabilities?
  • Does the FTC test provide useful insight on thermal performance?
  • To what extent is thermal performance correlated with long-term amplifier reliability?
  • Is any data available on the average failure rate of amps from the 1970s and '80s versus amps from the last 5-10 years?
And one more bullet point:

Is the procedure defined in the FTC test clear and unambiguous? Is it written to the level of, say, an ASTM standard which multiple labs can perform without communication to one another and get comparable results?
 
Humorous response on a different thread on the "5 minute" rule. Looks like a more reasonable test employed as well.

Post in thread '2nd generation EIGENTAKT PURIFI 1ET6525SA (successor to the 1ET400A)' https://audiosciencereview.com/foru...a-successor-to-the-1et400a.56549/post-2156364

Yes, it is a more reasonable test for thermal performance ........(the same I said I'd like to see in #857.)

Test being, determine the wattage at the onset of light clipping, using full-bandwidth pink with a 12 dB crest factor as a proxy for music (like pink CTA-2034).
Such a test signal has long been regarded as a reasonable proxy for music, and is typically described as 1/8th of rated power in proaudio spec sheets.

With respect to thermal capacity, I think any amp that can't indefinitely run at 1/8th of its rated wattage using this test signal, is plain junk.
 
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There different points of view at this thread for sure,it's not only about technical stuff (which yes,are not defined) it's cultural as well.
Europe has been forged under the "Dura lex, sed lex" (hard law,but law) ,that's why we use to beat something to death before becoming law.
And as far as I searched ,there was court case in Europe,find none in US.
US seems to be the other way around,comments to the FTC before the law was a fraction of this thread!

Most importantly,this thread (specially @restorer-john and @pma ) at points is like asking ASR to enforce this law.
That's not practical (most of the gear tested other than the far east ones are member's items,they want them back) ,neither obligatory .
That's on the companies side and if they decide to follow and agree on a procedure maybe the need to cross check will come at this place too.

And then there's the consumer side.It's the one pushing "300W in the 2-coilers",the one who has calculated everything to the last db,the easy one with the gazzilion of reserves,etc.Too broad of an umbrella,and the broader it is the more difficult to explain.The bare minimum doesn't cut it here.
So,an amp has to do everything under it's rated specs.
Someone has to rate it though.
 
As a side note I would expect to have the informed opinions of the other side at this thread,there's a bunch of them otherwise very vocal,both assemblers and designers.
They must have some more info about it.
Don't want to tag them but silence is strange.I would expect they were the first to participate.

Lol, really?

On one hand, I get your sentiment. However, if I was a busy business owner though, would steer way clear of this thread even if I had a decent position. The proposition looks like this to me: Here come visit our active minefield thread and the thread owner’s main goal is torture test your product. Hang around and burn your valuable time just for grins and try to not get blown to bits or publicly castrated!

Hmm, somehow my guess is they will be looking for most anything else to do. :D
 
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Lol, really?

On one hand, I get your sentiment. However, if I was a busy business owner though, would steer way clear of this thread even if I had a decent position. The proposition looks like this to me: Here come visit our active minefield thread and the thread owner’s main goal is torture test your product. Hang around and burn your valuable time just for grins and try to not get blown to bits or publicly castrated!

Hmm, somehow my guess is they will be looking to do most anything else to do. :D
Really.
Sometimes we judge others through ourselves.I think of myself on the other side.

What has an honest,technical competent company has to afraid of a thread trying to find out the new (US) market conditions?
Truth can't blown to bits,that's why ASR is nice and known for.They can say for example "that's my view,that's my goals" as Amir does,or whoever.

And sooner or later this will emerge everywhere,forums all around talk about this and a lot of members are quite surprised by the way numbers are produced,a lot thought otherwise,despite the many times we have talked about mere seconds or ms these tests last.

It's nice to know.

Edit: an another.
These numbers were made famous on the back of the older tested amps.Who doesn't remember the epic debates when UCD's came to market and they advertised their numbers back then?
Hundreds of them got blown in diyaudio trying to replicate the numbers,half of them with linear,beefy supplies too.When stuff settled we knew about time constrains,etc,no matter the thermals sometimes (except active,that delivers) .
 
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Really.
Sometimes we judge others through ourselves.I think of myself on the other side.

What has an honest,technical competent company has to afraid of a thread trying to find out the new (US) market conditions?
Truth can't blown to bits,that's why ASR is nice and known for.They can say for example "that's my view,that's my goals" as Amir does,or whoever.

And sooner or later this will emerge everywhere,forums all around talk about this and a lot of members are quite surprised by the way numbers are produced,a lot thought otherwise,despite the many times we have talked about mere seconds or ms these tests last.

It's nice to know.

Edit: an another.
These numbers were made famous on the back of the older tested amps.Who doesn't remember the epic debates when UCD's came to market and they advertised their numbers back then?
Hundreds of them got blown in diyaudio trying to replicate the numbers,half of them with linear,beefy supplies too.When stuff settled we knew about time constrains,etc,no matter the thermals sometimes (except active,that delivers) .

Agree, we all have our biases.

When an amp manufacturer shows up and actively engages here, will be the first to admit my error!
 
Really.
Sometimes we judge others through ourselves.I think of myself on the other side.

What has an honest,technical competent company has to afraid of a thread trying to find out the new (US) market conditions?

I think part of @Rick Sykora 's point was precisely that: if you think of yourself on the other side, in this case that of a manufacturer, why would they want to engage in this thread in particular, when as Rick has noted, it's very predictable what response an amp-maker will get? @pma and especially @restorer-john would love nothing more than to have the opportunity to pounce directly on someone from a company selling Hypex or Purifi-based amps in this thread.

On a related note, I'm not sure from whose side this is "a thread trying to find out the new (US) market conditions" - this thread isn't about market conditions at all.

I would be much more sympathetic to your point of view if it were about amp makers participating in ASR in general. But this thread is about the last place you'd want to weigh in, if you were an amp manufacturer. The signal to noise ratio is dreadful, and there are very vocal folks including the OP whose entire purpose here is to tell you (the amp maker) that you're selling a fraudulently advertised and/or substandard and/or "toy" product.
 
I think part of @Rick Sykora 's point was precisely that: if you think of yourself on the other side, in this case that of a manufacturer, why would they want to engage in this thread in particular, when as Rick has noted, it's very predictable what response an amp-maker will get? @pma and especially @restorer-john would love nothing more than to have the opportunity to pounce directly on someone from a company selling Hypex or Purifi-based amps in this thread.

On a related note, I'm not sure from whose side this is "a thread trying to find out the new (US) market conditions" - this thread isn't about market conditions at all.

I would be much more sympathetic to your point of view if it were about amp makers participating in ASR in general. But this thread is about the last place you'd want to weigh in, if you were an amp manufacturer. The signal to noise ratio is dreadful, and there are very vocal folks including the OP whose entire purpose here is to tell you (the amp maker) that you're selling a fraudulently advertised and/or substandard and/or "toy" product.
Don't think anyone will think of a nice Purifi implementation as a toy.
I play with a Audiophonics one all the time for example.
It's not a monster,ok,but decent,has basic thermals,etc.
Even @pma likes them!
 
Don't think anyone will think of a nice Purifi implementation as a toy.
I play with a Audiophonics one all the time for example.
It's not a monster,ok,but decent,has basic thermals,etc.
Even @pma likes them!

But @restorer-john has shown himself more than willing, again and again (and again), to label all Class D amps as "toys," and to engage in ever-escalating negative characterizations and accusations of those he disagrees with. If I'm one of the amp makers who participates in other threads here at ASR, why would I jump in to this one when I know there's a very good chance that John will immediately say something to the effect of, "Why don't you advertise your amps based on real FTC-mandated power ratings? Why do you advertise fraudulent power numbers when these amps are toys not designed to be able to sustain that output? Don't you know you're committing fraud?"

And he would only escalate from there.

Your point, @Sokel , is quite reasonable - but it's clear that there's an element of the arguments in this thread that has nothing to do with reason, and no rational amp maker would rely on self-restraint from some of the more shall-we-say passionate commenters in this thread.
 
But @restorer-john has shown himself more than willing, again and again (and again), to label all Class D amps as "toys," and to engage in ever-escalating negative characterizations and accusations of those he disagrees with. If I'm one of the amp makers who participates in other threads here at ASR, why would I jump in to this one when I know there's a very good chance that John will immediately say something to the effect of, "Why don't you advertise your amps based on real FTC-mandated power ratings? Why do you advertise fraudulent power numbers when these amps are toys not designed to be able to sustain that output? Don't you know you're committing fraud?"

And he would only escalate from there.

Your point, @Sokel , is quite reasonable - but it's clear that there's an element of the arguments in this thread that has nothing to do with reason, and no rational amp maker would rely on self-restraint from some of the more shall-we-say passionate commenters in this thread.
There's no @restorer-john enough to ask the questions they ask themselves I think.Publically or not.
I get that some of them may not want to engage as they will fall short,mostly at thermals,mostly with Hypex's bigger modules (barely enough with small Purifis though,I already did the math)

Especially for Purifi,it's a kind a blessing for the class D market,as it's astonishing efficiency let people speculate that all other class D are around there.They are not,not by a long shot.We know that already.If only they could built a PSU with such performance.

I guess the ones who search,eventually find the data-sheets and get the right info,after all it's a hobby,not a necessity.So...
 
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