Power consumption – JBL MPC User Manual
Page 18
17
Power Consumption
Some background on AC ratings is necessary to fully understand power consumption
specifications. Essentially, there are three ratings of interest: (1) the legal operating current as
measured by the Safety Agencies, (2) the maximum expected average current draw under
worst-case program material, and (3) the peak current draw at full output power.
All major safety agencies around the world measure amplifier current and temperature rise
under the same normal operation conditions, using a pink noise signal with an average
power equal to 1/8 of maximum rated average power. To put this level in perspective, typical
music and speech signals contain peaks of 12 dB to 20 dB above the average signal level, so
operating at 1/8 of rated average power will typically result in heavily clipped program
material.
JBL engineering standards call for the ability to operate at 1/3 power, in order to meet worst-
case demands.
The electrical current consumption at 120 VAC for each audio power level and load impedance
is shown in the table below. Multiply the current figures by 0.5 for 230 VAC operation.
Note: the audio test signal for 1/8 and 1/3 power testing is pink noise; the signal for full-
power testing is a 1 kHz sine wave.
l
e
d
o
M
d
a
o
L
l
e
n
n
a
h
C
r
e
w
o
P
l
l
u
F
r
e
w
o
P
3
/
1
*
r
e
w
o
P
8
/
1
e
l
d
I
,
0
0
2
C
P
M
T
0
0
2
C
P
M
8
Ω
8
+
Ω
A
7
.
5
A
4
.
3
A
3
.
2
A
4
.
0
4
Ω
4
+
Ω
A
2
.
9
A
2
.
5
A
5
.
3
A
4
.
0
2
Ω
2
+
Ω
A
3
.
3
1
A
4
.
7
A
9
.
4
A
4
.
0
V
0
0
1
,
V
0
7
,
V
5
2
A
7
.
8
A
0
.
5
A
3
.
3
A
4
.
0
,
0
0
3
C
P
M
T
0
0
3
C
P
M
8
Ω
8
+
Ω
A
7
.
7
A
9
.
4
A
3
.
3
A
6
.
0
4
Ω
4
+
Ω
A
5
.
2
1
A
4
.
7
A
8
.
4
A
6
.
0
2
Ω
2
+
Ω
A
8
.
8
1
A
0
.
1
1
A
2
.
7
A
6
.
0
V
0
0
1
,
V
0
7
,
V
5
2
A
2
.
1
1
A
7
.
6
A
5
.
4
A
6
.
0
,
0
0
6
C
P
M
T
0
0
6
C
P
M
8
Ω
8
+
Ω
A
7
.
4
1
A
4
.
8
A
5
.
4
A
8
.
0
4
Ω
4
+
Ω
A
3
2
A
4
.
2
1
A
1
.
6
A
8
.
0
2
Ω
2
+
Ω
A
3
3
A
5
.
6
1
A
0
.
8
A
8
.
0
V
0
0
1
,
V
0
7
,
V
5
2
A
1
2
A
9
.
0
1
A
7
.
5
A
8
.
0
* Analogous to normal audio program with moderate to heavy clipping.