Crown ma-1202 Guía De Referencia

Crown International, Inc.

P.O. Box 1000

Elkhart, IN 46515-1000

TEL: 219-294-8200

FAX: 219-294-8FAX

www.crownaudio.com

MA-2402

08/00                                                            131509-1  

 

For more details refer to the applicable Reference Manual or 

Contact Crown Audio Technical Support. The provided data 

should not be construed as specifications.

Crown and Macro-Tech are registered trademarks of Crown 

International, Inc. Printed in U.S.A.
© 2000 Crown International, Inc.

This document provides detailed information about the amount of power 

and current drawn from the AC mains by the Macro-Tech 2402 

amplifier and the amount of heat produced under various conditions. 

The calculations presented here are intended to provide a realistic 

and reliable depiction of the amplifier. The following assumptions 

or approximations were made:

•    The  amplifier’s  available  channels  are  loaded  and  full  power  is  being 

delivered.

•    The  amplifier  efficiency  at  standard  1-kHz  power  is  estimated  to  be 

65%.

•    Quiescent power draw is approximately 90 watts.
•    Quiescent thermal dissipation equals 105 btu/hr at 90 watts.
•    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 Figure 1:

The quiescent power draw of 90 watts is a maximum value and includes 

power drawn by the fan. 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 inefficiency 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: