BENCHMARK: Audio application notes – Feed-Forward Error Correction

John Siau writes:

The Benchmark AHB2 power amplifier and HPA4 headphone amplifier both feature feed-forward error correction. This correction system is an important subset of the patented THX-AAA™ (Achromatic Audio Amplifier) technology. It is one of the systems that keeps these Benchmark amplifiers virtually distortion free when driving heavy loads.

It is also the reason that these amplifiers can support 500 kHz bandwidths without risk of instability when driving reactive loads. The feed-forward system also helps to drive the output stage through the push-pull crossover region while providing a wide-bandwidth correction signal that virtually eliminates crossover distortion.

Feedback Error Correction

Feedback is a fundamental building block in audio amplifiers and in most any electrical or mechanical system. The basic concept is that a system output can be compared to a reference input in order to drive the output toward the reference.

Feedback drives the output toward the reference to reduce the difference between the reference and the output. The difference between the reference and the output is the error signal (or distortion) that we are attempting to minimize.

Combined use of Feedback and Feed-Forward Correction

I should point out that the Benchmark amplifiers .......

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