A common question we get here at the Listening Post is "how many watts does this amp produce?" It makes sense, rather like asking the horsepower of an engine; it's worth knowing as it indicates a lot about the performance. But it's not the whole story.
Recently I did a demo in store with some Dynaudio DM 3/7s. They were running from our modest amplifier that we keep in our first demo room. It is an NAD 356 that can output 80w. The sound really didn't thrill to be honest. It was weak, lacking definition and dynamics and simply wasn't easy to enjoy. Now I'm not saying that the amp was flawed, or the speakers, rather the combination wasn't ideal.
In order to get the most out of these speakers, I swapped the amp out for another. But the one I chose was only capable of 50 watts, instead of 80. Seems like it will only be worse right? Well that wasn't so.
Dynaudio DM3/7: Power hungry?
The amp I chose was the Moon 250i and it has one key difference: current.
NAD C356: Great all rounder.
Moon Neo 250i: Truly high fidelity.
Think of it this way; wattage is the amount of power that can flow through the amp at any given time. The problem with that number is it doesn't tell you how well that flow can push against resistance, how promptly that flow can begin or stop when needed or how stable and even the flow is.
The units of measurement regarding these aspects are not commonly published for a good reason; they're hard to market. It's a pity but it's true. We forgive our brands for this simplification as choosing an amp would be a blur of strange units, miniscule or massive numbers, strange ratios and odd coefficients otherwise. Luckily there is a simple trick to know what the amp is like without looking at these stats; pick it up. That's right, pick it up, the heavier the better. This is because the power supply (the source of current/watts) constitutes most of the weight of an amp and the grander the power circuits, the heavier it will be.
"...there is a simple trick to know what the amp is like..."
Back to our NAD and the Moon. The Moon is around half the size of the NAD and produces only 60% of the wattage, but weighs twice as much! And the performance really follows suit. With the Moon connected, the bass was significantly more controlled and punchier, the dynamics increased dramatically, voice was clearer and cut through the layers of the song and the finesse of the high end was there where it wasn't before. Pretty much everything was better.
In summary, wattage is a simple way to get an idea of what the amp can do, but theres nothing like sitting down in front of one and listening to it, physically touching and using it and hearing the result. So next time you're looking at a new amp, keep this in mind and march on in store and experience these things for yourself because numbers on a screen are nothing compared to soundwaves in your ears.
By the way, if we see you going amp by amp around the store picking them up and putting them straight back down, we won't think you're a weirdo, we'll join in!