Crown Audio 402and 602 Stereo Amplifier User Manual


 
XLS Series Power Amplifiers
page 19
Operation Manual
This section provides detailed information about the amount of power
and current drawn from the AC mains by XLS amplifiers and the amount
of heat produced under various conditions. The calculations presented
here are intended to provide a realistic and reliable depiction of the
amplifiers. The following assumptions or approximations were made:
• The amplifier’s available channels are loaded, and full power is being
delivered.
• Efficiency at standard 1 kHz power into 4 ohms is 63% for the XLS
602, 57% for the XLS 402, and 49% for the XLS 202.
• Quiescent power draw is 26W for the XLS 602, 23W for the XLS 402,
and 19W for the XLS 202.
• XLS 602 quiescent thermal dissipation equals 88 btu/hr at 0 watts
with 4 and 8 ohm loads.
• The estimated duty cycles take into account the typical crest factor for
each type of source material.
• Duty cycle of pink noise is 50%.
• Duty cycle of highly compressed rock ‘n’ roll midrange is 40%.
• Duty cycle of rock ‘n’ roll is 30%.
• Duty cycle of background music is 20%.
• Duty cycle of continuous speech is 10%.
• Duty cycle of infrequent, short duration paging is 1%.
Here are the equations used to calculate the data presented in Figures
7.1, 7.2 and 7.3:
The value used for amplifier inefficiency is (1.00-Efficiency). The factor
3.415 converts watts to btu/hr. Thermal dissipation in btu is divided by
the constant 3.968 to get kcal.
7 AC Power Draw and Thermal Dissipation