FTC Amplifier Rule Amendment Final Ruling:

[curt_c]

Provided Link: http://www.ftc.gov/os/2000/12/amplifierrulefrn.pdf


With the power amp thread going on below, I thought I'd give you a link to the FTC document.
-No, I didn't read all 34 pages, I kept falling asleep...

The changes to the original 1974 document are summarized below:

The Preconditioning has been reduced from 1/3 rated power to 1/8 rated power. To my mind, this allows smaller heat sinks to be utilized, or the ability to provide a 2 ohm spec. -I personally don't see this as an issue as 1/8 power is probably a more representitive of an average continous level.

Also for 'media advertising' they do not have to specify the THD, bandwidth, or impedance utilized for a specific power claim, as they 'contain little information for today's consumers.' -IOW, they think you are so dumb that you won't understand it anyway.

C

Here's the gist of it. The full ruling is at the link below:

"The Commission subsequently issued in the July 19, 1999 Federal Register a Notice of Proposed Rulemaking (NPR) that solicited public comment on specific proposed amendments to the Rule to:

reduce the power output requirement during the one-hour preconditioning period from one-third of rated output to one-eighth of rated output, and grant testers of self-powered subwoofers the discretion to choose the frequency of the test signal to be used during the preconditioning period;

exempt advertising disseminated through the media from disclosure of total rated harmonic distortion and the associated power bandwidth and impedance ratings when a power output claim is made; and allow the subwoofer and satellite amplifier sections in combination self-powered speaker systems to be driven to full rated power separately, rather than simultaneously, during the power rating tests."

[pjay]

Provided Link: my site


I got to the second paragraph. ZZZzzzzzzzz

You realize one of our own here on this board probably wrote that. But I am keeping my mouth shut.

P

[Jeff B.]

> I got to the second paragraph. ZZZzzzzzzzz

> You realize one of our own here on this
> board probably wrote that. But I am keeping
> my mouth shut.

> P

Yes, I believe he probably did. I was just wondering if he would want to clear up any questions. I don't really think the new standard is a big deal. It was really just meant to deal with multi-channel amplifiers which have a single power supply, and don't really expect all channels to driven hard simultaneously in the first place.

Jeff B.

[bill]

> Yes, I believe he probably did. I was just
> wondering if he would want to clear up any
> questions. I don't really think the new
> standard is a big deal. It was really just
> meant to deal with multi-channel amplifiers
> which have a single power supply, and don't
> really expect all channels to driven hard
> simultaneously in the first place.

> Jeff B.

Well, the preconditioning change is probably fairer; a Class AB amp dissipates maximum power at 1/3 rated output, so the old preconditioning requirement meant you had to have larger heatsinks than would ever be required with real program material, just to keep the amp from burning up before the actual test. I'm not as happy about the other change, though; I think the power supply needs to be able to handle all channels at full power simultaneously. Normal program material is pretty well correlated; in fact, audio compression systems rely on this correlation to reduce bit rate.

Best regards,
Bill

[Dirk]

> I'm not as happy about the
> other change, though; I think the power
> supply needs to be able to handle all
> channels at full power simultaneously.

Maybe it's the "conspiracy theorist" in me, but I have to think that the "one channel driven" comes from manufacturer lobbyist. Think about all of the companies that would have to scrape 2/3 of the listed power from their entire product line. New models would be VERY hard to push on the sheeple who all of a sudden saw little compelling reason to trade in that 3-year-old "500W" KLH for a 35Wpc.

Sony would be livid... ;-)

D.

PS: Bill, I was off the radar for a while. Did you get any traction on your line-level BSC box?

[severius]

>New models would be
> VERY hard to push on the sheeple who all of
> a sudden saw little compelling reason to
> trade in that 3-year-old "500W"
> KLH for a 35Wpc. > Sony would be livid... ;-)

Absolutely true. Conspiracy nothing.

So --- how can a clear headed guy like you go for those airless, grungy pro amps??

[dancarroll]

Sheeple, hmm. Wonder who you listen to?

Back to the main topic. Part of the continuing dumbing down of America. I am going to be characteristially immodest and say I ain't no dummy, nor are most of our compatriates here. I will also be characteristically self-deprecating and say that science and math are not my strong points. So there is an internal battle there. But to think that a normal old ordinary person can't understand a basic lay description of the relationship between THD and claimed power is, indeed, to think most everyone is dumb. Despite my liberal arts non-science brain, I can understand it enough to know that the lower the THD over 20 to 20K, the more likely the power ratings are real. So can a typical consumer, if someone takes the time to explain it and the consumer takes the time to listen and think just a tiny bit. It would not bug me so much except every ad for equipment you see says "X watts per channel" -- so sales are made based on those claims, which I now know are not only incomplete (which I already knew) but also are legally allowed to be incomplete.

Sheesh. In what is supposed to be a free marketplace (though it really isn't, as most of us know), more information is better than less. What is so hard to understand about that? If Soccer Mom or Too Busy at Work Dad choose to ignore it, that is their business, but that does not mean the information should not be there for folks who care about it.

[bill]

Well, I lost the napkin (really!) so I was kinda scratching my head for a while, but I think I've recreated the design, this time in my notebook. Don't know why it took so long; it's not very complicated. Anyhow, I haven't built it yet, but it's on the list. I have to dig up my prototyping sockets and +/-15 volt supply.

Best regards,
Bill

> Maybe it's the "conspiracy
> theorist" in me, but I have to think
> that the "one channel driven"
> comes from manufacturer lobbyist. Think
> about all of the companies that would have
> to scrape 2/3 of the listed power from their
> entire product line. New models would be
> VERY hard to push on the sheeple who all of
> a sudden saw little compelling reason to
> trade in that 3-year-old "500W"
> KLH for a 35Wpc.

> Sony would be livid... ;-)

> D.

> PS: Bill, I was off the radar for a while.
> Did you get any traction on your line-level
> BSC box?

[Dirk]

> Absolutely true. Conspiracy nothing.

> So --- how can a clear headed guy like you
> go for those airless, grungy pro amps??

Grungy pro amps? That's not me, holmes. I've got a Yamaha receiver acting as a pre/pro with a Parasound HCA-1000A. Hope that passes muster. ;-)

[Dirk]

> Sheeple, hmm. Wonder who you listen to?

Eh? I don't follow. Are you attacking my sexual, religous or political beliefs? Whichever is fine, just curious. ;-)

> that? If Soccer Mom or Too Busy at Work Dad
> choose to ignore it, that is their business,
> but that does not mean the information
> should not be there for folks who care about
> it.

I agree. But also, who is supposed to tell SM or TBaWD how these ratings work? Or the defining characteristics of the underlaying standards that they likely take for granted? Consider "watts" in hair dryers, microwaves, and light bulbs. Or amps in vacuum cleaners. How are those ratings different (at a glance) from the number of watts in your stereo? Bigger numbers are better, all other things being equal, aren't they?

The problem lies in the fact that the average Joe believes those equalites are rational and less deceiving than they really are--and they have no reason to believe otherwise.

In my humble opinion and all that. ;-)

All in good debate,
D.

[Dirk]

> Well, I lost the napkin (really!) so I was
> kinda scratching my head for a while, but I
> think I've recreated the design, this time
> in my notebook. Don't know why it took so
> long; it's not very complicated. Anyhow, I
> haven't built it yet, but it's on the list.
> I have to dig up my prototyping sockets and
> +/-15 volt supply.

> Best regards,
> Bill

Not a standard DC wall wort?

[bill]

> Not a standard DC wall wort?

Well, I designed it as a bench simulation tool or something I might want to add into an active speaker system built around chip amps. No problem getting bipolar supplies for either of those.

You could run it single-ended, but then you need to worry about DC blocking. Lots of big caps. Yuck.

You've got mail, BTW.

Best regards,
Bill

[bobleeqsc]

There's a lot more to the dumbing down than just an FTC rule. A lot of amp buyers think the THD number in a power spec is an indicator of distortion performance instead of a definition of the onset of clipping.