IEC 62368-1-Annex E.2 Testing box | Audio amplifier normal
operating temperature measurements box
Test conditions for equipment containing audio amplifiers
E.2
Audio amplifier normal operating conditions
Equipment containing an audio amplifier shall be operated using a
sine wave audio signal source at a frequency of 1 000 Hz. In
the case where an amplifier is not intended for operation at 1
000 Hz, the peak response frequency shall be used.
The equipment shall be operated in such a way as to deliver 1/8
non-clipped output power to the rated load impedance.
Alternatively, a band-limited pink noise signal may be used
for operation after non-clipped output power is established
using a sine wave. The noise bandwidth of the pink noise test
signal shall be limited by a filter of a characteristic as
shown in Figure E.1.
If visible clipping cannot be established, the maximum attainable
power shall be considered as the non-clipped output power.
In addition, all of the following conditions shall be considered
under normal operating conditions:
– The most unfavourable rated load impedance or the actual
loudspeaker, when provided,is connected to the amplifier output.
– All amplifier channels are operated simultaneously.
– Organs or similar instruments that have a tone-generator unit
shall not be operated with the 1 000 Hz signal, but instead be
operated with any combination of two bass pedal keys,if present,
and ten manual keys depressed. All stops and tabs that can increase
the output power shall be activated and the equipment shall be
adjusted to deliver 1/8 of the maximum attainable output
power.
– Where the intended amplifier function depends on phase
difference between two channels, there shall be a phase
difference of 90° between signals applied to the two channels.
–For equipment containing multi-channel amplifiers, where some
channels cannot be operated independently, those channels
shall be operated using the rated load impedance at the output
power level that corresponds, by design, to 1/8 of
the non-clipped output power of the adjustable amplifier
channel(s).
–Where continuous operation is not possible, the amplifier shall be
operated at the maximum output power level that allows
continuous operation.
The temperature measurements shall be carried out with the
equipment positioned in accordance with the instruction manual
provided by the manufacturer, or, in the absence
of instructions, the equipment shall be positioned 5 cm behind
the front edge of an open-fronted wooden test box with 1 cm
free space along the sides and top and 5 cm depth behind
the equipment.
