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? 
128x128redstarwraith

Showing 1 response by boomerbillone

Hello redstarwraith.  From all the responses, you can see that opinions differ, and some folks just like to argue. Layman's terms? "Not everyone tell the truth. Manufacturers want to sell stuff." POWER should be a simple matter of math. An amp that doubles it's 8 ohm output into 4 ohms should sound better than one that doesn't. Many ad writers have no idea what they are talking about. Many amp designers feel they make the perfect amp and if your speakers don't like them, too bad. Even today, many amp designers don’t realize that the power supply of the amp is it’s most important section. Some amp designers want to help out the speakers with some electronic wizardry. Some speakers don't like wizards. Some do. And that's why speaker cables matter. In general, small speakers are less efficient than large speakers, but not always.

If you have Maggies (I've had two pair of them and think highly of them), realize they have a weakness; they are less "dynamic" than cone loudspeakers. their diaphragms cannot move large distances and thus cannot move large amounts of air. What they have is near magical clarity and exemplary electrical behavior. With almost any amp, they will sound less dynamic (flashy, zippy, theatrical) than some other speaker. Add a subwoofer if you want more "impact" from your music system. Emotiva's amps do well with Maggies; I suspect Shiit amps will do well also. You can buy them on line and send them back if they don't work well for you. NAD is famous for making amps that "sound bigger" than their ratings. Use at least 14 gauge zip cord for speaker cables. Keep them short if you can. Cables matter. Many highly rated speakers have dreadful electrical characteristics and count on a very tolerant amp to get good results. Tolerant amps tend to be pricey. You can build very good amps, speakers, and cables for relatively little money. If the website lets you, contact me directly for "how to" info.

The room matters more than we like to think. You won't get good sound in a closet full of clothes. Does your room have surfaces that reflect or absorb sound? Speaker placement within the room is critical. Six inches one way or another can make a huge difference. It is a particular problem in the bass. Away from walls is better than close to walls, but I insist on being able to walk across my room without bumping into speakers.

A good 100 watt, class A/B (that means it shifts between two operating modes, A and B), should be enough for most situations, excepting stadiums. Do not rely on advertiser's claims. Your practical experience is more important than anyone's words. Enjoy the hobby!