Crown MA-36-X-12 Brochure

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MA-36x12

M A C R O - T E C H S E R I ES

AC Power Draw and Thermal Dissipation

The information provided on this page is calculated data based on driv­ing both channels to rated output using the 1 kHz Maximum Average
Power rating method.

Other parameters used in calculation include a conservative idle current
estimate of 90 watts and a conservative estimate of effeciency at 65%.

Information is provided only for getting an idea of current draw and heat
produced. Actual performance will vary depending on environment, pro­gram material, load, signal, and AC mains voltage and frequency.

Values of calculated current draw are intended to represent average draw
corresponding to the thermal breaker requriements that should be met to
handle the amplifier as a load on the AC mains.

Peak current draw with dynamic program material may be significantly
higher. Thermal information is provided to assist with calculating air
conditioning needs. The data here should not be construed as specifica­tions.

Duty cycle of various program material:

Individual speech: 10%
Acoustic/chamber music: 20%
Full-range rock music: 30%
Compressed rock music: 40%
Pink noise: 50%

Here are the equations used to calculate the data presented in Figure 1:

AC Mains Power

Draw (watts)

Total output power with all

channels driven (watts)

=

Amplifier Efficiency (.65)

x

Duty

Cycle

Quiescent Power

+

Draw (watts)

The quiescent power draw is a maximum value and includes power drawn by the fan. The
following equation converts power draw in watts to current draw in amperes:

AC Mains Power

Current Draw

(amperes)

=

AC Mains

Volta

Draw (watts)

x

e

Factor (.83

Power

The value used for Power Factor is 0.83. The Power Factor variable is needed to compen­sate for the differnece in phase between the AC mains voltage and current. The following
equation is used to calculate thermal dissipation:

Thermal

Dissipation

(btu/hr)

Total output power with all

channels driven (watts)

=

Amplifier Efficiency (.65)

Duty

x

Cycle

.35

x

Quiescent Power

+

Draw (watts)

x

3.415

The value used for 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. If you plan to
measure output power under real-world conditions, the following equation may also be
helpful:

Thermal

Dissipation

(btu/hr)

Total measured output power

from all channels (watts)

=

Amplifier Efficienc

(.65)

.35

x

Quiescent Power

+

Draw (watts)

x

3.415

Duty
Cycle

50%

40%

30%

20%

10%

AC Mains

Power

Draw

(Watts)

1190

970

750

530

310

8 Ohm

Current Draw (Amps)

100-120 V 230 V

12.0

9.7

7.5

5.3

3.1

6.2

5.1

3.9

2.8

1.6

Thermal Dissipation

btu/hr

kcal/hr

1622

1359

1096

833

570

409

342

276

210

144

A Harman International Company

Crown International, Inc.
1718 W. Mishawaka Rd.
Elkhart, IN 46517-9439
TEL: [phone]
FAX: [phone]FAX
www.crownaudio.com

AC Mains

Power

Draw

(Watts)

1663

1348

1034

719

405

Macro-Tech 36x12

L O A D

4 Ohm 2 Ohm

Current Draw (Amps)

16.7

13.5

10.4

7.2

4.1

Thermal Dissipation

btu/hr

2188

8.7

1812

7.1

1436

5.4

1059

3.4

2.1

683

For more details refer to the applicable Operation
Manual or contact Crown
provided data should not be construed as specif­ciations.
Crown and Crown Audio are registered trade­marks of Cown international, Inc. Printed in
U.S.A.
© 2005 Crown Audio

04/05 138416-1

kcal/hr100-120 V 230 V

551

457

362

267

172

®

Factory Service. The

®

, Inc.

AC Mains

Power

Draw

(Watts)

1994

1613

1232

852

471

Current Draw (Amps)

8.6

4.7

10.4

8.5

6.5

4.5

2.5

20.0

16.2

12.4

Thermal Dissipation

btu/hr

kcal/hr100-120 V 230 V

2583

2128

1673

1218

762

651

536

422

307

192