What's up with watts: how much power do you need?

The Audiophiliac offers advice about amplifier power

Steve Guttenberg
Ex-movie theater projectionist Steve Guttenberg has also worked as a high-end audio salesman, and as a record producer. Steve currently reviews audio products for CNET and works as a freelance writer for Stereophile.
Steve Guttenberg
2 min read

Amplifier power is measured in watts, as in "100 watts per channel," but what does that really mean? Do all 100 watt per channel receivers deliver 100 watts? And what about those "1000 watt" home theater in a box systems? Are they more powerful than 2,000 A/V receivers? And what about high-end 100 watt per channel high-end power amps? Are all watts created equal? I don't think so!

Pass Labs 200 watt XA200 amplifier weighs 175 pounds Pass Labs

Unfortunately power ratings are a near meaningless way to compare the loudness potential of one receiver, amplifier, or HTIB against another. That's what power gets you--the more power you put into a given speaker--the louder it will play. More watts aren't necessarily better sounding watts; some hard-core audiophiles get off listening to ultra low power, 7 watt per channel, hand-built, vacuum tube amplifiers. These guys think the purity of the watts is where it's at.

Sure, most of us want more, not less power, but the catch is there's no reliable way for a consumer to learn about a given amp, receiver, or HTIB's wattage. Oh, there's one specification that has served me well over the years: weight. Power is heavy, or to be more precise, the stuff that makes power is heavy. I'm sorry, but a 9 pound HTIB amplifier has about as much chance of putting out 1000 watts as I do. I pretty much guarantee that a 44 pound receiver will clobber a 22 pounder when it comes to dishing out King Kong's room shaking antics. Look under the hood of a high-end amp or pricey A/V receiver and you see a humongous power transformer. Powerful amps need big transformers to pull a lot of power from the wall outlet, and high current transformers are always heavy things. The other power supply related parts are also big, heavy, and, well, not cheap. Fact is, most $500 A/V receivers never come close to delivering their spec-ed power into their seven channels. Some can barely manage a third of their claimed wattage.

The reasons the manufacturers "get away" with this outright fraud are numerous, but the reality is most buyers don't listen all that loud. If you do and/or live a big house or apartment, or have speakers that demand oodles of juice, pony up and buy a serious receiver or better yet, a separates based system with a surround processor and heavyweight power amp. One hundred watts per channel might not be enough, or 200 might be better, but an honest-to-God 300 watts might be what it takes to rock your world. Even if it's just the occasional party where you really want to blast the system, you need to buy enough power. When in doubt, go for more, and don't worry about damaging your speakers with too much power. Fact is, more speakers get fried by underpowered amps than by uber power amps. In other words, you're more likely to "blow up" a speaker with a 25 watt amp than a 250 watter.