Newport Test Labs measured the both-channelsdriven into an 8-ohm power output of the Adcom GFA-555se at 288 watts (24.6dBw) per channel at 1kHz, but at the frequency extremes of 20Hz and 20kHz the output was just a little less, at 276 watts (24.4dBw) per channel. However, despite being slightly less, these ‘on-test’ figures still put the GFA-555se handily above its 200 watt per channel specification by 76 watts (1.4dB).
When only a single channel was driven into the same load, the GFA-555se's measured output power increased to 310 watts (24.9dBw) per channel at 20Hz and 20kHz, and to 318 watts (25dBw) at 1kHz. All of these figures are shown in the accompanying tabulated result table, and graphically on the bar-charts.
Driven into 4-ohm loads, measured the power output of the GFA-555se at exactly 400 watts per
