IEC 60268-3:2013 applies to analogue amplifiers, and the analogue parts of analogue/digital amplifiers, which form part of a sound system for professional or household applications. It specifies the characteristics which should be included in specifications of amplifiers and the corresponding methods of measurement. This fourth edition cancels and replaces the third edition published in 2000 and constitutes a technical revision. It includes the following technical changes: - rated condition of multi-channel amplifier is expanded; - arrangement for the D-class amplifier is added; - method of measurement for output power (distortion-limited) is expanded; - Annex B is newly added. This publication is to be read in conjunction with IEC 60268-1:1985 and IEC 60268-2:1987