Lab.gruppen LAB 300 - Manual (Page 3)

Introduction
Thank you for purchasing a LAB.GRUPPEN power amplifier. This manual contains important information on
operating your amplifier correctly and safely. Please take some time and read this manual to familiarize yourself
with the amplifier.
The front panel
Figure 1. Front panel
1. Carry/protection handle
Both handles can be used to carry the amplifier, they
also act as protection for the front panel. If so desired
they can be removed (by removing the screws behind
the front panel and replacing the handles with nuts)
for fixed installations, or racks where the front
covers are to shallow.
2. Input level attenuators
These controls are used to alter the signal level
entering the amplifier. They are calibrated in dB to
help set up active loudspeaker systems or cut down
unwanted noise from the input signal.
(See page 7).
3. Protect indicator (Temperature and VHF)
This indicator is lit if the amplifier tries to operate
above its maximum operating temperature (90
o C).
The indicator first comes on as a warning, to either
turn down the input level, or check the cooling
arrangements after what point
the amplifier will mute the input signal. When the
cooling has returned the output heat sinks to the
normal operating temperature, the input signal is
unmuted.
This indicator also lights when constant signals,
above 20 kHz at full power, are present at the output
terminals. When this happens the input signal is
muted and the process cycles until the VHF signal is
no longer present. (See page 8).
4. Clip/limit indicator
This indicator tells when the amplifier output is
clipping or limiting. The two different states can be
told apart:
• When the clip limiter is engaged it flickers
briefly. (See page 8).
• When the clip limiter is not engaged it lights for
a longer period.
5. Power actuator
This is used to start the amplifier. (See page 4 and 7).
The rear panel
Figure 2. Rear panel
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