Originally Posted by Modifry Products

Does anybody know if these HU have a built-in DC-DC converter to step up the power supply voltage? I ask because these power numbers sound higher than the math allows.

When looking at amp specs, remember that "RMS power" does not necessarily mean "sine wave power". RMS is simply a means of measuring power for a non-DC signal; it doesn't always mean the signal is an audio (sine wave) signal.

When they quote "maximum RMS power" they are probably describing a situation where the amp is over-driven to the point where you get nothing but square waves on the output (100% distortion), which is in fact the maximum amount of power the amp can deliver. This is not usable power, as you would have turned the volume down long before you get to this level of distortion. But assuming this condition exists (square waves) and you're using a 14.4 volt power source with zero power losses in every part of the circuit, the most power you can put into a 4Ω load is 51.8 watts. With a sine wave signal the maximum power is half of that (25.9W). Of course, in the real world there are losses everywhere so you're likely to get 75-80% of that.