Watts and power


Can somebody break it down in layman's terms for me? Why is it that sometimes an amp that has a high watt rating (like, say, a lot of class D amps do) don't seem to always have the balls that much lower rated A or AB amps do? I have heard some people say, "It's not the watts, it's the power supply." Are they talking about big honkin' toroidal transformers? I know opinions vary on a speaker like, say, Magnepans - Maggies love power, right? A lot of people caution against using class D amps to drive them and then will turn around and say that a receiver like the Outlaw RR2160 (rated at 110 watts into 8 ohms) drives Maggies really well! I'm not really asking about differences between Class D, A, or AB so much as I am asking about how can you tell the POWER an amp has from the specs? 
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Most tube amps don't have "guts" in the bass due to low damping factor. You may prefer that or you may not and that will be room / speaker dependent. 


That dip in impedance is a factor of woofer electro-electromechanical properties and sometimes a 2.5/3.5 way folding in another driver. Crossover may shunt current from woofer to tame a peak.
I doubt that audio savvy people drive tube amps to clipping when actively listening unless that listening involves heavy drinking and dancing with lampshade headwear. I used to be able to easily demonstrate where my 12Wpc tube amp clipped because my main speakers were around 90db efficiency, but now that I'm using 99db horn loaded Heresy IIIs they simply get way too loud for that sort of thing. Still, I rely on tube distortion with guitar amps, but even in a "clean" mode they are so much better sounding overall that there's no contest with the silly "modeling" amps or any SS guitar amps. Some jazz dudes still use SS amps, but many don't (John Pizzarelli borrowed a little tube amp from me at a concert last year...a 15 watt Reverend Goblin, and the brilliant Matt Munisteri used a mint 64 Fender Princeton Reverb with Katherine Russell). Tubes "seem" faster and snappier in hifi and elsewhere. Or so they say, and I agree.
Can somebody break it down in layman's terms for me?


And so one after another all he gets is a bunch of technical info. When the answer in layman's terms is actually in this case absolutely identical to the answer in technical terms: THERE IS NO ANSWER IN TECHNICAL TERMS!

Every single one of the supposed answers above, most of which sound sensible, a few of which maybe even are, nevertheless are easily proven to be nonsense. All these things are at best factors. But remember- correlation is not causation!

What happens, and OP it will really help if you can learn this one early, is someone hears an amp that sounds unusually powerful compared to its watt rating. So they look for reasons. Perfectly natural thing to do, look for reasons. Let's say they find the amp is capable of delivering a lot of current. Wow that must be the reason! Unfortunately, sorry, BS, which is demonstrated as easily as listening to another low current amp that seems to sound just as powerful, if not even more so.

The same can be done for every single one of the other technical reasons listed above, and a whole lot more we haven't yet gotten around to. Not to worry, the people incapable of noticing the request for layman's terms are equally incapable of putting a damper on their need to show off with word salad. Er, technobabble. Er I mean technical knowledge.

Oh and by the way, you can go through and replace "power" and watts with just about anything you want- liquid vs etched, 3D vs flat, dynamic vs damped, any and all of it. Sometimes there's really good causes you can point to. When faster diodes are swapped and the sound improves its fairly easy to point to the speed and recovery of the diode. Although even then its wrong to say the speed is the reason- because there are even faster diodes that sound worse, and maybe even slower ones that sound better.

Now take that one part, the lowly diode, multiply it by a thousand for all the parts in a component. Then multiply that by a hundred for all the different circuit topologies (the way the circuits are physically laid out) then multiply that by a handful more for the way the chassis and, well you get the idea. Or at least I hope you do. There's just way more variables involved than you can ever hope to understand, let alone boil down to one simple number. To then point to that number and say, "THIS is why!" Is simplistic and shortsided in the extreme.


In a way, I like @millercarbon's answer, despite leaving me with the feeling that there really are no good answers.  So far, that squares with my experience; any time I think I see a correlation between any particular amp parameter and the quality of sound I hear, along comes another amp that breaks the rule.  Having said that, I would still like to find a book that tries to address how power, output current, speaker/crossover characteristics and other factors affect what we hear from a given amp/speaker pairing.  Does anyone know if such an animal exists?
Miller as usual puts a lot of words down that mean exactly nothing. Actually your last post said absolutely nothing. Lots of snark and veiled insults but no actual info.


Tube amps may hit above their weight because they can often be driven into clipping without sounding awful and YES people with low power tube amps do this.


Other than that, looks at watts at the low of your speakers impedance. One amp that does 100 watts and 4 ohms and 200 at 2 ohms is not the same rating as 100 at 4 and 150 at 2 if your speaker dips to 2 ohms. 


Other than that, mainly comes down to headroom provided by the power suppl both the voltage and capacitance and a beefy enough output stage to deliver short term peaks. There is no magic, no ethereal effects ... Just basic low level engineering. Flowery words are meaningless.