2. amps-preamps
  3. 153225-130247

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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Showing 1 response by nekoaudio

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nekoaudio
489 posts
 
Reading through the posts so far, the answers from @georgehifi read the most correctly to me.

Watts, or power, is equal to voltage multiplied by current. But an individual speaker may want more voltage at some frequencies, versus more current at other frequencies. And if your amplifier is limited in one of those dimensions, it will have trouble driving the speaker.

There are other amplifier considerations for sound quality, but specifically to the question of high power ratings not having drive capability, it's the current and voltage numbers you are looking for.

The SPL calculator referenced earlier assumes a simple speaker load and unlimited current/voltage capability. I use it too, but only as a guide.
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