Operation; Starting Procedures; Signal Level Adjustments; Ground Lift Switch - Stac Force 180 Mode D'emploi

Fig. 4.1
Outputs
STEREO MODE
2
Speakon pin layout:
1+ ⇒1+
1- ⇒ 1-
Abb. 4.2
STEREO MODE
Binding-Post
+
-
Abb. 4.3
BRIDGE MODE
Wiring = red to red
+
-
12
1
2+ ⇒
not connected
2- ⇒
+
-
-
+
+
-
Owner`s manual FORCE 180 STAC Audio

5. Operation

5.1 Starting procedures

After the FORCE 180 has been connected to the
mains supply and the other devices according to
the instructions, it is ready for operation. To avoid
accidental feedback which might damage the
speakers, it is advisable to rotate the volume
controls CHANNEL 1 (10) and CHANNEL 2 (11)
fully counterclockwise before switching on the
amplifier.
After these precautions have been taken, the
FORCE 180 is ready to be switched on with the
POWER switch (12). The amplifier is ready for
operation when the LED (13) above the POWER
switch is bright.

5.2 Signal level adjustments

With an audio signal connected to the amplifier's
inputs, carefully rotate the volume controls
CHANNEL 1 (10) and CHANNEL 2 (11) clockwise
until the SIGNAL LEDs (6 or 7) start flashing. The
CLIP LEDs (8) should just not flash at signal
peaks. With these level adjustments, the overall
volume of the PA system can be adjusted with the
master output faders of the mixing console. The
volume controls of the FORCE 180 should need
readjustments only when the CLIP LEDs start
flashing during operation.

5.3 Ground lift switch (15)

Occasionally, a loud hum can be heard after a PA
system has been switched on, usually as a result
of a 'ground loop' inside your setup. Is this case,
using the GROUND switch (15) may interrupt the
ground loop and stop the hum. In its FRAME
position, the signal ground is connected to the
amplifier's earth (case), in the FLOAT position,
signal ground is not connected to earth (see fig.5).
If the hum cannot be eliminated this way, contact
an authorized STAC dealer for assistance.
FLOAT GROUND FRAME