Crown Audio 4300 operation manual AC Power Draw and Thermal Dissipation

Xs 4300

X s S E R I E S

AC Power Draw and Thermal Dissipation

This document provides detailed information about the amount of power and current drawn from the AC mains by the Crown® Xs 4300 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 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 55.5%.

•Quiescent power draw is 38.1 W.

•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:

								Xs 4300
								Xs 4300
										L O A D
			2 Ohm Stereo						4 Ohm Stereo						8 Ohm Stereo
	AC	Current Draw			Thermal		AC	Current Draw			Thermal		AC	Current Draw			Thermal
		(Amps)			Dissipation			(Amps)			Dissipation			(Amps)			Dissipation
Duty	Mains						Mains						Mains
	Power						Power						Power
Cycle
	Draw	120V		230V	btu/hr	kcal/hr	Draw	120V		230V	btu/hr	kcal/hr	Draw	120V		230V	btu/hr	kcal/hr
	(W)						(W)						(W)
50%							1119	14.3		7.5	1773	447	759	9.7		5.1	1225	309
40%							903	11.6		6.0	1444	364	615	7.9		4.1	1006	254
30%							687	8.8		4.6	1116	281	471	6.0		3.1	787	198
20%							471	6.0		3.1	787	198	326	4.2		2.2	568	143
10%							254	3.3		1.7	459	116	182	2.3		1.2	349	88

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: 574-294-8200

FAX: 574-294-8FAX

www.crownaudio.com

For more details refer to the applicable Operation Manual or contact Crown Factory Service. The provided data should not be construed as specifications.

Crown is a registered trademark of Crown International, Inc. Printed in U.S.A.

© 2003 Crown Audio, Inc.

04/03 135178-1