LABORATORY TEST REPORT

Newport Test Labs measured the power output of the Cary Audio SI-300.2d at 1kHz as being 325-watts per channel both channels driven into 8 loads, and 506-watts per channel, both channels driven into 4 loads, so the amplifier met Cary’s own specified ratings of 300-watts into 8 and 450-watts into 4 , the latter by a considerable margin.

The amplifier proved unable to sustain its rated output when both channels were driven at a frequency of 20Hz, with the 8 result coming in at 276-watts per channel, and the 4 result at 380-watts per channel. However, as these results are only 0.36dB and does not hold the 240V mains power constant during testing, the difference in output is of no consequence. The power output at 20kHz is suffixed by an asterisk because it’s an estimation, because whereas usually measures just before the onset of visible clipping at this frequency, the output waveform of the Cary Audio SI-300.2d distorts well before it clips, presumably as a result of one or more of the output protection circuits, and while these circuits will operate with continuous test signals, they’re unlikely to cut in when music is being played, since there’s so little energy in music signals at this high frequency. The takeaway here is that there’s more than sufficient power—at any frequency in the audio band—for any conceivable home hi-fi application.