DD Audio SA500.1SA Series amplifiers are compact amplifiers with full size features. The SA500. 1 is a 1 ohm stable monoblock subwoofer amplifier with a continous output power of 500 watts. Even though the SA Series amplifiers are very compact they still employ set screw power and speaker terminals, different input sections, and heavy duty aluminum heatsinks. This ensures power management is proper from input to output, increasing both in use stability and long term