We’ve had a few people inquire about many of the new power amplifiers appearing on the scene that appear to have more available power at their output than possible, or that boast extremely high output power while sucking relatively little electrical current. A good example is the Crown K2 amplifier, which boasts 2500 watts into a mono four ohm load, yet they claim just draws a few amps of power. If the amp was plugged into a 120 volt, 20 amp circuit it would have to be nearly 100% efficient to be able to produce 2500 watts (Volts x Amps = Watts), and no power amp is anywhere near 100% efficient. What gives?
Some people have accused them of playing games with the numbers, but anyone who knows Crown knows they just don’t do this. First, these new Crown amps (as well as some other competitive designs) are extremely efficient. So efficient, in fact, that they don’t even require a fan to keep cool. Very little energy is lost in these designs. Second, reproducing music signals is actually far less demanding on an amplifier then producing sine waves or other steady state signals. The dynamics of music material dictate that an amplifier spends the majority of its time operating at a fraction of its rated power output. If the amp is hyper-efficient like a K2, then it can operate drawing just a few amps of current under normal circumstances. The numbers that Crown gives often relate more to how the products are used in practice as opposed to theoretical benchmark tests. There is much more information on their Web site about the design principles at work in their amps.