QSC Audio CX Series Heat Emissions, Model, Ac Current Consumption, CX4, CX4T, CX6, CX6T

AC Current Consumption

AC CURRENT CONSUMPTION

A major objective in the design of the CX Series amplifiers—even the higher-powered models—is to permit their operation from readily available, standard AC power sources.

“Normal conditions” in power amplifier rating means operating with a random program source (pink noise), using pink noise as a source, at an average power level equal to one-eighth of maximum power. This is recognized by most of the world’s safety agencies as the loudest you can play music through an amplifier and still keep the incidence of clipping to a reasonable minimum. An amplifier’s peak current draw at full output power into 2 ohms is several times what the “normal” draw is, but its various protection circuits will prevent this condition from lasting more than a minute or two.

When you plan the AC power hookups for your amplifiers, use the following table to predict the current requirements per ampli- fier. You can use the one-

Model			8Ω		4Ω	or Distributed Line			2Ω
	IDLE	FULL	1/3	1/8	FULL	1/3	1/8	FULL	1/3	1/8
		POWER	POWER	POWER	POWER	POWER	POWER	POWER	POWER	POWER
CX4, CX4T	0.4A	6.0A	2.8A	2.5A	10A	4.5A	3.8A	15A	6.8A	5.6A
CX6, CX6T	0.9A	7.9A	4.3A	3.2A	13A	7.5A	5.0A	19A	10A	7.0A
CX12, CX12T	1.0A	15A	8.6A	5.1A	24A	12A	6.5A	33A	17A	8.5A

eighth power figures to predict the normal continu- ous current draw, then add a safety margin to allow for occasional crescendos.

HEAT EMISSIONS

Essentially, a power amplifier draws electrical energy from the AC mains, converts it to DC, and then converts it again into an analog of the input signal to send out to the loudspeakers. Any AC power that enters the amplifier through the power cord and does not exit through the speaker outputs turns into heat, which the amplifier must rid itself of by exhausting it to the outside. In indoor use, multiple amplifiers may present a sizeable challenge to a building’s air conditioning system. Use the table below to predict the heat that will be emitted by your amplifier. Use one-eighth power for normal, continuous usage.

Heat Emissions

Model				8Ω		4Ω	or Distributed Line			2Ω
		IDLE	FULL	1/3	1/8	FULL	1/3	1/8	FULL	1/3	1/8
			POWER	POWER	POWER	POWER	POWER	POWER	POWER	POWER	POWER
	Btu/hr	110			490			765			1545
CX4, CX4T
(preliminary)	kcal/hr	28			123			193			389
CX6, CX6T	Btu/hr	250	890	735	735	1630	1655	905	3145	2205	1655
	kcal/hr	63	224	185	185	411	417	228	793	556	417
CX12, CX12T	Btu/hr	265	1725	1530	945	3250	2395	1360	5545	3785	2230
	kcal/hr	67	435	386	238	819	604	343	1397	954	562

29