In Benchmark's listening room we recently demonstrated the importance of the first watt using two 100 watt stereo power amplifiers. One amplifier was a traditional class-AB amplifier, the other was Benchmark's AHB2 power amplifier with feed-forward error correction. Using a double-blind ABX test, we verified that there was a clearly audible difference when the amplifiers drove speakers at an output level of 0.01 watt.
This short 8-second video clip demonstrates some of the differences.
The following measurements and scope photos demonstrate the effectiveness of the feedforward system in the AHB2.
From the first Watt to the last Watt, the AHB2 shows no evidence of crossover distortion. In contrast, all conventional class-AB amplifiers have crossover-distortion artifacts.
Dick Olsher once said that "the first Watt is the most important Watt". We agree!
Most audio power amplifiers suffer from a defect known as "crossover distortion". This distortion is particularly troublesome at low output levels. At low power levels, the crossover distortion can rise to a high percentage of the output level and become the dominant source of distortion.