MACKIE TH-18S - Manual (Page 10)

10
7. LEVEL
The LEVEL control adjusts the overall signal level at
the input to the built-in power amplifier. It ranges from
-6 dB to +6 dB (maximum gain), with unity gain at the
center position (12 o’clock).
The control has no effect on the level of the high-
pass outputs [5] or the full-range outputs [4].
8. THERMAL LED
The TH-18s is equipped with a thermal protection
circuit that monitors the internal temperature of the
amplifiers and heatsink. If the temperature exceeds a
safe operating level, this indicator lights and the input
signal is muted to allow the amplifiers to cool. When
the temperature cools to a safe level once again, the
thermal protection circuit deactivates, the Thermal
LED turns off and the TH-18s returns to normal
operation.
When the TH-18s is in thermal protect mode, the
power LED [11] will remain lit, indicating that the unit
is still powered on despite the lack of output.
Activation of the thermal protection circuit
is an indication that you should take steps
to avoid continued thermal problems. See
“Thermal Protection” on page 12.
9. OL LED
The OL (overload) indicator lights when the
amplifier in the TH-18s is near the clipping point. It is
okay if the OL indicator blinks occasionally, because
this means that the transient peaks are just reaching
the maximum output of the amplifier and you are
getting the most from your TH-18s.
If the OL indicator is blinking frequently or lighting
continuously, turn down the LEVEL control [7] on the
TH-18s or turn down the signal at it source
(e.g., the mixing console) until the OL indicator blinks
occasionally or not at all.
10. SIGNAL LED
This LED illuminates green whenever there is a
signal present at the main input connector. It senses the
signal just after the Level control, so adjustments to the
level control will affect the signal indicator.
11. POWER LED
This LED illuminates when the power switch [2] is
turned on and the linecord is connected to an active AC
Mains supply.
TH-18s
ACTIVE SOUND
REINFORCEMENT SUBWOOFER
REVISION SERIAL NUMBER
WARNING:
TO REDUCE THE RISK OF FIRE OR ELECTRIC
SHOCK, DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR
MOISTURE. DO NOT REMOVE COVER. NO USER SERVICEABLE
PARTS INSIDE. REFER SERVICING TO QUALIFIED PERSONNEL.
AVIS: RISQUE DE CHOC ELECTRIQUE — NE PAS OUVRIR
POWER
ON
B A
INPUTS
B A
B A
OUTPUTS
HIGH PASS
FULL RANGE
LEVEL
OL SIGNAL POWER
POLARITY
NORMAL
INVERT
THERMAL
R
+ 6dB 6dB -
11 8
7
6
5
4
3
9 10