1
LED POWER INDICATOR
The green LED POWER indicator, located on the back of
the amplifier, will illuminate when the AC Power switch is in
the “ON” position. The LED POWER indicator will dim and
turn off when the AC Power switch is in the “OFF” position or
AC mains power has been disconnected from the loudspeaker.
If the POWER indicator does not illuminate when the
loudspeaker is powered on, verify the AC mains line cord is
properly connected to the loudspeaker and inserted into
the AC outlet. Verify the AC outlet at the venue of operation
is functioning properly. In the event of the AC mains outlet
functioning properly, but the loudspeaker fails to operate,
the loudspeaker may require servicing. Please contact
[email protected] for service instructions.
2
PROTECT LED INDICATOR
If the power module overheats, the amplifier will go
into “protection mode” to limit further temperature rise. The
amplifier will take about 30 seconds to several minutes for
the temperature to drop and resume operation. When this
occurs, the exposed heat sink will feel hot to the touch.
3
3 LIMIT LED INDICATOR
The ASM-12/ASC-12 amplifier employs a sophisticated
compressor-limiter circuitry, which is nearly inaudible at
moderate overdrive conditions. It is normal to see the
occasional flashing of the red LIMIT LED.
Continuous Bright Red Light
Indicates continuous and gross overloading of the
amplifier. Such overloads are audible and may lead to
overheating of the amplifier and shortening the life of the
speaker components. If the amplifier is grossly overloaded
and the red LIMIT LED is on the most of the time, the
operator should reduce the signal level so that LIMIT LED
only flashes occasionally.
4
SIGNAL LED INDICATOR
The green SIGNAL indicator alerts the operator to the presence of
an input signal at the loudspeaker amplifier.
If there is no indication, check the gain settings on the amplifier
and increase the gain if necessary. Check input connections and
audio source for signal. If no output persists, try a different signal
cable from your Digital Amplifier to the ASM-12/ASC-12 loudspeaker.
5
LEVEL CONTROL
Turn the LEVEL control clockwise to increase gain and counter
clockwise to decrease gain. When operating with the GAIN set at
1/3 volume or below, it may be possible to exceed the headroom
of input circuitry on your loudspeaker. If this is the case, reduce the
input signal strength and increase the gain of the loudspeaker
amplifier.
Always observe the red LIMIT LED on the amplifier panel. This LED
lights when a signal is clipping and the compressor-limiter is
activated. The ASM-12/ASC-12 amplifier employs a sophisticated
limiter circuitry, which monitors signal condition at both LF and HF
amplifiers and compresses the output signal when necessary to
protect woofer and compression driver from damages. Limiter
circuitry works very unobtrusively; you may not even notice when it
activates. It may prompt you to push input signal more, but it is a
good practice to have red LIMIT LEDs blink occasionally and not
constantly. A constant LIMIT LED light indicates a gross overloading
condition and should be avoided. Reduce the signal level if the LIMIT
LED lights or blinks constantly.
NOTE that LEVEL control provides about 12dB attenuation in
middle position. You will find that in most cases the best sound
(lowest distortions and lowest noise) will be achieved when LEVEL
control is set somewhere between middle and full clockwise
position.
6
LOW CUT SWITCH
ASM-12/ASC-12: Found beneath the LEVEL control, this small slider
switch engages or disengages the 100Hz 18db/Octave Low Cut filter.
Indicates that the amplifier is clipping briefly causing
overdrive distortion and the internal limiter is reducing
gain.
Momentary Bright Red Flashes
The red LIMIT indicator alerts the user that the amplifier
output signal is clipping and therefore is being compressed
by the built-in clip-limiter.
If the green SIGNAL LED remains illuminated without a source
connected, the amp may need servicing.
Overheating is usually caused by excessive ambient
temperature, direct sunlight for a prolonged period of
time during operation, or playing the loudspeaker past its
operational limits.
If thermal overheating occurs, reduce signal level to avoid
constant illumination of the LIMIT LED INDICATOR. In some
circumstances, for example when ambient temperature is
too high, you may need to set a fan behind the speaker to
improve ventilation at heatsink.
NOTE that LEVEL Control has a range of 30dB. It does not
attenuate output signal to zero. LEVEL control on the
loudspeaker is used to set optimal maximum level for
performance, not for constant control of sound volume. Your
Digital Amplifier’s master volume control should be used for this.
