Pioneer’s Class-D amps transform very little power into heat so a higher percentage of the power supply (67 %) is transformed into the load. This results in a very compact amp which needs less input power to produce very high output power. The Class-D amplifier’s PWM (Pulse Width Modulator) modulates the original audio input signal with a triangulated signal wave which has a much higher fixed frequency. The result is a digital signal which contains both the input signal and a band of frequency components around the modulation frequency.