ATC SCM20 - Page 8

ACTIVE
SCM20ASL/ASLT SECTION FOUR
Should a loudspeaker fail to switch on when the power switch is operated, the fuse should be inspected. Lift out the fuse holder cover using a small
at-blade screwdriver, remove the fuse and inspect for damage. If required, a replacement fuse should be tted. Ratings are printed on the amp rear
panel. It should be stressed, however, that fuses most often fail only because of a serious electrical fault. If this is the case, then simply replacing the
fuse will only result in another fuse failure. In the case of a second fuse failure, please contact your local ATC representative in the rst instance for
support. Details can be found on the ATC website.
The audio signal cable should be connected here. Balanced or unbalanced cables may be used.
This control adjusts the amp and speaker output level with respect to the input level. A higher sensitivity means less voltage is needed at the input
for a given output level (higher gain). A lower sensitivity means more voltage is needed at the input for a given output level.
This user adjustment is made up of two controls:
a) Selector Switch – This switch toggles between 1V/+2.2dBu and 2V/+8.2dBu input sensitivity (for full amp output). Choose the setting that best
suits the source/pre-amp combination.
b) Sensitivity Trim – Input sensitivity can be further ne-tuned using the Input Sensitivity Trim.
Note: For source (driving) equipment with potentiometer based analogue level control, choose an input sensitivity that results in the desired average
sound pressure level with the source level control at approximately 50%. For source (driving) equipment with a digital level control, choose an input
sensitivity that results in the desired average sound pressure level with the level control at approximately 80%.
This control provides ne adjustment of input sensitivity. Fully clockwise is the factory ‘reference’ position of 0dB. In this position, the trim has no eect
on the input sensitivity which is controlled by the switch described above. Turning the control anti-clockwise will result in up to -6dB of adjustment.
The combination of the two controls gives a total input sensitivity range of 1V/+2.2dBu to 4V/+14.2dBu (for full amplier output of 200W).
This button powers the loudspeaker on or o. When the switch is in the inward position the loudspeaker is powered on. When the switch is in
the outward position the loudspeaker is powered o.
Due to the nature of the electronics in
ATC active loudspeakers it is quite normal for a sound to be heard from the speaker when the power is applied or
disconnected. The noise heard will not damage the speaker and is quite normal. Although ATC uses the highest-grade components, a dierent noise may be
heard from each speaker due to slight tolerance variations in the amplier components.
The supplied mains power lead (appropriate to the local territory) should be connected here. Ensure that the mains voltage specied on the panel
corresponds with the local supply voltage.
Fuse HolderControl Panel Operation
Power on/off
4.3
4.1
Mains Inlet
Input Socket
Input Sensitivity
4.2
4.4
4.5
WARNING
THIS EQUIPMENT
MUST BE EARTHED
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
MAINS INPUT
50/60Hz
POWER CONSUMPTION
335VA MAX
CHECK VOLTAGE
BEFORE USE
1V
2.2dBu
2V
8.2dBu
balanced input
input sensitivity
(for 200W out)
2
1
3
1:
2:
3:
fuse
230V - 2.5A
115V - 5A
on
+3
+2
+1
-1
-2
0
-3
-6
bass shelf:
cut/boost (dB)
trim(dB)
serial number
voltage
FAULT:
vertemp/
Acoustic Transducer Co. is a trading name and is
the registered Trade Mark of Loudspeaker Te chnology Ltd.
input impedance
10k Ω/leg
DIAGRAM 5
Sensitivity Trim
4.6