Lab.gruppen LAB 4000 User Manual page 6

The power consumption according to the chart above is then 1300 watts.
The heat power produced is the difference between the power consumption and output power;
1300 - 525 = 775 watts per amplifier.
8. Input connections
XLR Input connectors are balanced and wired
according to the IEC 268, that is pin 2 hot, and
wired in the following way:
PIN 1 GROUND/SHIELD
PIN 2 HOT
PIN 3 COLD
Figure 3. XLR input connector pinout
There are also TRS jacks for linking etc. They are
wired as follows:
TIP HOT
RING COLD
SLEEVE SHIELD/GROUND
Figure 4. TRS phone plug
The input impedance is high enough (20 kohms
balanced) to allow "daisy-chaining", or multiple
parallel input connections. To daisy chain, use the
TRS jacks provided on each channel. The input
circuits also have a high enough headroom, to accept
the maximum output level from virtually any low
level signal source.
Figure 5. Rear panel connectors
INPUT
CH. B
Mono Bridge
XLR 1 / 4 "
Pin 1 Gnd Sleeve
2 Pos Tip
3 Neg Ring
230V AC 40-440Hz
Must be grounded
Power consumption: 2300 watts
Do not use XLR and TRS jacks on the same
channel simultaneously for mixing or other
purposes.
CH. A
4 0 0 0
Figure 6. Balanced line
To connect an unbalanced source, tie pin 3 (ring on
TRS jack) down to the shield of the connector. If
you leave one pin disconnected, you will lose 6 dB
in gain.
Figure 7. Unbalanced line connection
A more optimal method for handling unbalanced
sources is shown in Figure 8.This is similar to the
connection for balanced lines, but pin 3 is tied down
to shield, at the source side instead. The hum and
noise rejection for the cable is equivalent to that for a
balanced line. To minimize hum in the audio, use
balanced inputs whenever possible.
Fi
gure 8. Balanced line with unbalanced equipment
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