Crown CH-1 Brochure

C O N T R A C T O R S E R I E S
CH1
This document provides detailed information about the amount of power and current drawn from the AC mains by the CH1 amplier and the amount of heat produced under various conditions. The calculations pre­sented here are intended to provide a realistic and reliable depiction of the amplier. The following assumptions or approximations were made:
• The amplier’s available channels are loaded and full power is being delivered.
• The amplier efciency at standard 1-kHz power is estimated to be 65%.
• Quiescent power draw is approximately 60 watts.
• When running at full speed, typical power draw for the internal fan is 12 watts or less.
• 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%.
AC Power Draw and Thermal Dissipation
Here are the equations used to calculate the data presented in Figure 1:
The following equation converts power draw in watts to current draw in amperes:
The value used for Power Factor is 0.83. The Power Factor variable is needed to compensate for the difference in phase between the AC mains voltage and current. The following equation is used to calculate thermal dissipation:
The value used for inefciency is 0.35 (1.00–0.65). The factor 3.415 converts watts to btu/hr. Thermal dissipation in btu is divided by the constant 3.968 to get kcal. If you plan to measure output power under real-world conditions, the following equation may also be helpful:
Figure 1 Power Draw, Current Draw and Thermal Dissipation at Various Duty Cycles
Crown International, Inc. P.O. Box 1000 Elkhart, IN 46515-1000 TEL: 219-294-8200 FAX: 219-294-8FAX www.crownaudio.com
© 2000 Crown International, Inc.
08/00 131512-1
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