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An Active Load and Test Method for Evaluating the Efficiency of Audio Power Amplifiers

This paper presents the design, implementation and use of an “active load” for audio power amplifier efficiency testing. The active load can simulate linear complex loads representative of real-world amplifier operation with a load modulus between 4 and 50 ohms inclusive, load phase-angles between −60° and +60° inclusive, and operates from 20 to 20,000 Hz. The active load allows for the development of an automated test procedure for evaluating the efficiency of an audio power amplifier across a range of output voltage amplitudes, load configurations and output signal frequencies. The results of testing a class-B and a class-D amplifier, each rated at 100 watts into 8 ohms are presented.

Authors: Dymond, Harry; Mellor, Phil
Affiliation: University of Bristol
AES Convention:125 (October 2008) Paper Number:7572 Import into BibTeX
Subject:Amplifiers and Automotive Audio

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