IEC 60268-3:2013

IEC 60268-3 ®
Edition 4.0 2013-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Sound system equipment –
Part 3: Amplifiers
Équipements pour systèmes électroacoustiques –
Partie 3: Amplificateurs
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IEC 60268-3 ®
Edition 4.0 2013-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Sound system equipment –
Part 3: Amplifiers
Équipements pour systèmes électroacoustiques –

Partie 3: Amplificateurs
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XB
ICS 33.160.10 ISBN 978-2-83220-735-2

– 2 – 60268-3  IEC:2013
CONTENTS
FOREWORD . 5

1 Scope . 7

2 Normative references . 7

3 Conditions . 8

3.1 Rated conditions and standard measuring conditions . 8

3.1.1 Overview . 8

3.1.2 Rated conditions . 8

3.1.3 Standard measuring conditions . 9
3.2 Other conditions . 9
4 Classes of operation . 9
5 Interchangeable parts . 10
6 Automatic controls . 10
7 Power supply . 10
8 Position of the volume controls . 10
9 Pre-conditioning for measurements . 11
10 Series of measurements . 11
11 Variable consumption apparatus . 11
12 Marking . 11
13 Operating environment . 12
14 Characteristics to be specified, and their methods of measurement . 12
14.1 Power supply characteristics . 12
14.1.1 Characteristics to be specified . 12
14.1.2 Method of measurement . 12
14.2 Tolerance of (long-term) power supply voltage variations . 13
14.2.1 Characteristic to be specified . 13
14.2.2 Methods of measurement . 13
14.3 Tolerance of power supply frequency variations . 14
14.3.1 Characteristics to be specified . 14
14.3.2 Methods of measurement . 14
14.4 Tolerance of power supply harmonics and ripple . 15
14.4.1 Characteristics to be specified . 15

14.4.2 Methods of measurement . 15
14.5 Input characteristics . 15
14.5.1 Rated source impedance, characteristic to be specified . 15
14.5.2 Input impedance . 15
14.5.3 Rated source e.m.f., characteristic to be specified . 17
14.5.4 Minimum source e.m.f. for rated distortion-limited output voltage . 17
14.6 Output characteristics . 18
14.6.1 Rated load impedance, characteristic to be specified . 18
14.6.2 Output source impedance . 18
14.6.3 Output voltage and power (distortion-limited) . 19
14.6.4 Regulation . 20
14.6.5 Overload restoring time . 20
14.7 Limiting characteristics . 21
14.7.1 Overload source e.m.f. . 21

60268-3  IEC:2013 – 3 –
14.7.2 Short-term maximum output voltage and power . 21

14.7.3 Long-term maximum output voltage and power . 22

14.7.4 Temperature-limited output power . 23

14.8 Characteristics of protection circuits . 24

14.8.1 General . 24

14.8.2 Protection against potentially damaging combinations of output

voltage and current . 24

14.8.3 Characteristics of d.c. offset protection circuits . 25

14.9 Sustaining-time for rated (distortion-limited) output voltage or power . 26

14.9.1 General . 26

14.9.2 Characteristic to be specified . 27
14.9.3 Method of measurement . 28
14.10 Gain . 28
14.10.1  Voltage gain and e.m.f. gain . 28
14.10.2 Maximum e.m.f. gain . 28
14.10.3 Attenuation characteristic of the volume control . 28
14.10.4 Attenuation characteristic of balance controls for multi-channel
equipment . 29
14.11  Response . 30
14.11.1 Gain-frequency response . 30
14.11.2 Gain-limited effective frequency range . 30
14.11.3 Distortion-limited effective frequency range . 31
14.11.4 Phase-frequency response . 31
14.12 Amplitude non-linearity . 31
14.12.1 General . 31
14.12.2 Rated total harmonic distortion, characteristic to be specified . 31
14.12.3  Total harmonic distortion under standard measuring conditions . 32
14.12.4 Total harmonic distortion as a function of amplitude and frequency . 32
14.12.5  Harmonic distortion of the nth order under standard measuring
conditions . 33
14.12.6  Harmonic distortion of the nth order as a function of amplitude and
frequency . 34
14.12.7  Modulation distortion of the nth order (where n = 2 or n = 3) . 34
14.12.8 Difference-frequency distortion of the nth order (where n = 2 or n =
3) . 36
14.12.9 Dynamic intermodulation distortion (DIM) . 37

14.12.10 Total difference frequency distortion . 39
14.12.11 Weighted total harmoni
...